granicus.if.org Git - postgresql/blob - src/backend/commands/tablecmds.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * tablecmds.c
   4  *        Commands for creating and altering table structures and settings
   5  *
   6  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.269 2008/11/02 01:45:27 tgl Exp $
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include "access/genam.h"
  18 #include "access/heapam.h"
  19 #include "access/reloptions.h"
  20 #include "access/relscan.h"
  21 #include "access/sysattr.h"
  22 #include "access/xact.h"
  23 #include "catalog/catalog.h"
  24 #include "catalog/dependency.h"
  25 #include "catalog/heap.h"
  26 #include "catalog/index.h"
  27 #include "catalog/indexing.h"
  28 #include "catalog/namespace.h"
  29 #include "catalog/pg_constraint.h"
  30 #include "catalog/pg_depend.h"
  31 #include "catalog/pg_inherits.h"
  32 #include "catalog/pg_namespace.h"
  33 #include "catalog/pg_opclass.h"
  34 #include "catalog/pg_tablespace.h"
  35 #include "catalog/pg_trigger.h"
  36 #include "catalog/pg_type.h"
  37 #include "catalog/pg_type_fn.h"
  38 #include "catalog/toasting.h"
  39 #include "commands/cluster.h"
  40 #include "commands/defrem.h"
  41 #include "commands/sequence.h"
  42 #include "commands/tablecmds.h"
  43 #include "commands/tablespace.h"
  44 #include "commands/trigger.h"
  45 #include "commands/typecmds.h"
  46 #include "executor/executor.h"
  47 #include "miscadmin.h"
  48 #include "nodes/makefuncs.h"
  49 #include "nodes/nodeFuncs.h"
  50 #include "nodes/parsenodes.h"
  51 #include "optimizer/clauses.h"
  52 #include "optimizer/plancat.h"
  53 #include "optimizer/prep.h"
  54 #include "parser/gramparse.h"
  55 #include "parser/parse_clause.h"
  56 #include "parser/parse_coerce.h"
  57 #include "parser/parse_expr.h"
  58 #include "parser/parse_oper.h"
  59 #include "parser/parse_relation.h"
  60 #include "parser/parse_type.h"
  61 #include "parser/parse_utilcmd.h"
  62 #include "parser/parser.h"
  63 #include "rewrite/rewriteDefine.h"
  64 #include "rewrite/rewriteHandler.h"
  65 #include "storage/bufmgr.h"
  66 #include "storage/lmgr.h"
  67 #include "storage/smgr.h"
  68 #include "utils/acl.h"
  69 #include "utils/builtins.h"
  70 #include "utils/fmgroids.h"
  71 #include "utils/inval.h"
  72 #include "utils/lsyscache.h"
  73 #include "utils/memutils.h"
  74 #include "utils/relcache.h"
  75 #include "utils/snapmgr.h"
  76 #include "utils/syscache.h"
  77 #include "utils/tqual.h"
  78
  79
  80 /*
  81  * ON COMMIT action list
  82  */
  83 typedef struct OnCommitItem
  84 {
  85         Oid                     relid;                  /* relid of relation */
  86         OnCommitAction oncommit;        /* what to do at end of xact */
  87
  88         /*
  89          * If this entry was created during the current transaction,
  90          * creating_subid is the ID of the creating subxact; if created in a prior
  91          * transaction, creating_subid is zero.  If deleted during the current
  92          * transaction, deleting_subid is the ID of the deleting subxact; if no
  93          * deletion request is pending, deleting_subid is zero.
  94          */
  95         SubTransactionId creating_subid;
  96         SubTransactionId deleting_subid;
  97 } OnCommitItem;
  98
  99 static List *on_commits = NIL;
 100
 101
 102 /*
 103  * State information for ALTER TABLE
 104  *
 105  * The pending-work queue for an ALTER TABLE is a List of AlteredTableInfo
 106  * structs, one for each table modified by the operation (the named table
 107  * plus any child tables that are affected).  We save lists of subcommands
 108  * to apply to this table (possibly modified by parse transformation steps);
 109  * these lists will be executed in Phase 2.  If a Phase 3 step is needed,
 110  * necessary information is stored in the constraints and newvals lists.
 111  *
 112  * Phase 2 is divided into multiple passes; subcommands are executed in
 113  * a pass determined by subcommand type.
 114  */
 115
 116 #define AT_PASS_DROP                    0               /* DROP (all flavors) */
 117 #define AT_PASS_ALTER_TYPE              1               /* ALTER COLUMN TYPE */
 118 #define AT_PASS_OLD_INDEX               2               /* re-add existing indexes */
 119 #define AT_PASS_OLD_CONSTR              3               /* re-add existing constraints */
 120 #define AT_PASS_COL_ATTRS               4               /* set other column attributes */
 121 /* We could support a RENAME COLUMN pass here, but not currently used */
 122 #define AT_PASS_ADD_COL                 5               /* ADD COLUMN */
 123 #define AT_PASS_ADD_INDEX               6               /* ADD indexes */
 124 #define AT_PASS_ADD_CONSTR              7               /* ADD constraints, defaults */
 125 #define AT_PASS_MISC                    8               /* other stuff */
 126 #define AT_NUM_PASSES                   9
 127
 128 typedef struct AlteredTableInfo
 129 {
 130         /* Information saved before any work commences: */
 131         Oid                     relid;                  /* Relation to work on */
 132         char            relkind;                /* Its relkind */
 133         TupleDesc       oldDesc;                /* Pre-modification tuple descriptor */
 134         /* Information saved by Phase 1 for Phase 2: */
 135         List       *subcmds[AT_NUM_PASSES]; /* Lists of AlterTableCmd */
 136         /* Information saved by Phases 1/2 for Phase 3: */
 137         List       *constraints;        /* List of NewConstraint */
 138         List       *newvals;            /* List of NewColumnValue */
 139         bool            new_notnull;    /* T if we added new NOT NULL constraints */
 140         Oid                     newTableSpace;  /* new tablespace; 0 means no change */
 141         /* Objects to rebuild after completing ALTER TYPE operations */
 142         List       *changedConstraintOids;      /* OIDs of constraints to rebuild */
 143         List       *changedConstraintDefs;      /* string definitions of same */
 144         List       *changedIndexOids;           /* OIDs of indexes to rebuild */
 145         List       *changedIndexDefs;           /* string definitions of same */
 146 } AlteredTableInfo;
 147
 148 /* Struct describing one new constraint to check in Phase 3 scan */
 149 /* Note: new NOT NULL constraints are handled elsewhere */
 150 typedef struct NewConstraint
 151 {
 152         char       *name;                       /* Constraint name, or NULL if none */
 153         ConstrType      contype;                /* CHECK or FOREIGN */
 154         Oid                     refrelid;               /* PK rel, if FOREIGN */
 155         Oid                     conid;                  /* OID of pg_constraint entry, if FOREIGN */
 156         Node       *qual;                       /* Check expr or FkConstraint struct */
 157         List       *qualstate;          /* Execution state for CHECK */
 158 } NewConstraint;
 159
 160 /*
 161  * Struct describing one new column value that needs to be computed during
 162  * Phase 3 copy (this could be either a new column with a non-null default, or
 163  * a column that we're changing the type of).  Columns without such an entry
 164  * are just copied from the old table during ATRewriteTable.  Note that the
 165  * expr is an expression over *old* table values.
 166  */
 167 typedef struct NewColumnValue
 168 {
 169         AttrNumber      attnum;                 /* which column */
 170         Expr       *expr;                       /* expression to compute */
 171         ExprState  *exprstate;          /* execution state */
 172 } NewColumnValue;
 173
 174 /*
 175  * Error-reporting support for RemoveRelations
 176  */
 177 struct dropmsgstrings
 178 {
 179         char            kind;
 180         int                     nonexistent_code;
 181         const char *nonexistent_msg;
 182         const char *skipping_msg;
 183         const char *nota_msg;
 184         const char *drophint_msg;
 185 };
 186
 187 static const struct dropmsgstrings dropmsgstringarray[] = {
 188         {RELKIND_RELATION,
 189          ERRCODE_UNDEFINED_TABLE,
 190          gettext_noop("table \"%s\" does not exist"),
 191          gettext_noop("table \"%s\" does not exist, skipping"),
 192          gettext_noop("\"%s\" is not a table"),
 193          gettext_noop("Use DROP TABLE to remove a table.")},
 194         {RELKIND_SEQUENCE,
 195          ERRCODE_UNDEFINED_TABLE,
 196          gettext_noop("sequence \"%s\" does not exist"),
 197          gettext_noop("sequence \"%s\" does not exist, skipping"),
 198          gettext_noop("\"%s\" is not a sequence"),
 199          gettext_noop("Use DROP SEQUENCE to remove a sequence.")},
 200         {RELKIND_VIEW,
 201          ERRCODE_UNDEFINED_TABLE,
 202          gettext_noop("view \"%s\" does not exist"),
 203          gettext_noop("view \"%s\" does not exist, skipping"),
 204          gettext_noop("\"%s\" is not a view"),
 205          gettext_noop("Use DROP VIEW to remove a view.")},
 206         {RELKIND_INDEX,
 207          ERRCODE_UNDEFINED_OBJECT,
 208          gettext_noop("index \"%s\" does not exist"),
 209          gettext_noop("index \"%s\" does not exist, skipping"),
 210          gettext_noop("\"%s\" is not an index"),
 211          gettext_noop("Use DROP INDEX to remove an index.")},
 212         {RELKIND_COMPOSITE_TYPE,
 213          ERRCODE_UNDEFINED_OBJECT,
 214          gettext_noop("type \"%s\" does not exist"),
 215          gettext_noop("type \"%s\" does not exist, skipping"),
 216          gettext_noop("\"%s\" is not a type"),
 217          gettext_noop("Use DROP TYPE to remove a type.")},
 218         {'\0', 0, NULL, NULL, NULL, NULL}
 219 };
 220
 221
 222 static void truncate_check_rel(Relation rel);
 223 static List *MergeAttributes(List *schema, List *supers, bool istemp,
 224                                 List **supOids, List **supconstr, int *supOidCount);
 225 static bool MergeCheckConstraint(List *constraints, char *name, Node *expr);
 226 static bool change_varattnos_walker(Node *node, const AttrNumber *newattno);
 227 static void MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel);
 228 static void MergeConstraintsIntoExisting(Relation child_rel, Relation parent_rel);
 229 static void StoreCatalogInheritance(Oid relationId, List *supers);
 230 static void StoreCatalogInheritance1(Oid relationId, Oid parentOid,
 231                                                  int16 seqNumber, Relation inhRelation);
 232 static int      findAttrByName(const char *attributeName, List *schema);
 233 static void setRelhassubclassInRelation(Oid relationId, bool relhassubclass);
 234 static void AlterIndexNamespaces(Relation classRel, Relation rel,
 235                                          Oid oldNspOid, Oid newNspOid);
 236 static void AlterSeqNamespaces(Relation classRel, Relation rel,
 237                                    Oid oldNspOid, Oid newNspOid,
 238                                    const char *newNspName);
 239 static int transformColumnNameList(Oid relId, List *colList,
 240                                                 int16 *attnums, Oid *atttypids);
 241 static int transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
 242                                                    List **attnamelist,
 243                                                    int16 *attnums, Oid *atttypids,
 244                                                    Oid *opclasses);
 245 static Oid transformFkeyCheckAttrs(Relation pkrel,
 246                                                 int numattrs, int16 *attnums,
 247                                                 Oid *opclasses);
 248 static void validateForeignKeyConstraint(FkConstraint *fkconstraint,
 249                                                          Relation rel, Relation pkrel, Oid constraintOid);
 250 static void createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
 251                                                  Oid constraintOid);
 252 static void ATController(Relation rel, List *cmds, bool recurse);
 253 static void ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 254                   bool recurse, bool recursing);
 255 static void ATRewriteCatalogs(List **wqueue);
 256 static void ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 257                                           AlterTableCmd *cmd);
 258 static void ATRewriteTables(List **wqueue);
 259 static void ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap);
 260 static AlteredTableInfo *ATGetQueueEntry(List **wqueue, Relation rel);
 261 static void ATSimplePermissions(Relation rel, bool allowView);
 262 static void ATSimplePermissionsRelationOrIndex(Relation rel);
 263 static void ATSimpleRecursion(List **wqueue, Relation rel,
 264                                   AlterTableCmd *cmd, bool recurse);
 265 static void ATOneLevelRecursion(List **wqueue, Relation rel,
 266                                         AlterTableCmd *cmd);
 267 static void ATPrepAddColumn(List **wqueue, Relation rel, bool recurse,
 268                                 AlterTableCmd *cmd);
 269 static void ATExecAddColumn(AlteredTableInfo *tab, Relation rel,
 270                                 ColumnDef *colDef);
 271 static void add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid);
 272 static void ATExecDropNotNull(Relation rel, const char *colName);
 273 static void ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 274                                  const char *colName);
 275 static void ATExecColumnDefault(Relation rel, const char *colName,
 276                                         Node *newDefault);
 277 static void ATPrepSetStatistics(Relation rel, const char *colName,
 278                                         Node *flagValue);
 279 static void ATExecSetStatistics(Relation rel, const char *colName,
 280                                         Node *newValue);
 281 static void ATExecSetStorage(Relation rel, const char *colName,
 282                                  Node *newValue);
 283 static void ATExecDropColumn(Relation rel, const char *colName,
 284                                  DropBehavior behavior,
 285                                  bool recurse, bool recursing);
 286 static void ATExecAddIndex(AlteredTableInfo *tab, Relation rel,
 287                            IndexStmt *stmt, bool is_rebuild);
 288 static void ATExecAddConstraint(List **wqueue,
 289                                                                 AlteredTableInfo *tab, Relation rel,
 290                                                                 Node *newConstraint, bool recurse);
 291 static void ATAddCheckConstraint(List **wqueue,
 292                                                                  AlteredTableInfo *tab, Relation rel,
 293                                                                  Constraint *constr,
 294                                                                  bool recurse, bool recursing);
 295 static void ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel,
 296                                                   FkConstraint *fkconstraint);
 297 static void ATExecDropConstraint(Relation rel, const char *constrName,
 298                                                                  DropBehavior behavior,
 299                                                                  bool recurse, bool recursing);
 300 static void ATPrepAlterColumnType(List **wqueue,
 301                                           AlteredTableInfo *tab, Relation rel,
 302                                           bool recurse, bool recursing,
 303                                           AlterTableCmd *cmd);
 304 static void ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
 305                                           const char *colName, TypeName *typename);
 306 static void ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab);
 307 static void ATPostAlterTypeParse(char *cmd, List **wqueue);
 308 static void change_owner_recurse_to_sequences(Oid relationOid,
 309                                                                   Oid newOwnerId);
 310 static void ATExecClusterOn(Relation rel, const char *indexName);
 311 static void ATExecDropCluster(Relation rel);
 312 static void ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel,
 313                                         char *tablespacename);
 314 static void ATExecSetTableSpace(Oid tableOid, Oid newTableSpace);
 315 static void ATExecSetRelOptions(Relation rel, List *defList, bool isReset);
 316 static void ATExecEnableDisableTrigger(Relation rel, char *trigname,
 317                                                    char fires_when, bool skip_system);
 318 static void ATExecEnableDisableRule(Relation rel, char *rulename,
 319                                                 char fires_when);
 320 static void ATExecAddInherit(Relation rel, RangeVar *parent);
 321 static void ATExecDropInherit(Relation rel, RangeVar *parent);
 322 static void copy_relation_data(SMgrRelation rel, SMgrRelation dst,
 323                                                            ForkNumber forkNum, bool istemp);
 324
 325
 326 /* ----------------------------------------------------------------
 327  *              DefineRelation
 328  *                              Creates a new relation.
 329  *
 330  * If successful, returns the OID of the new relation.
 331  * ----------------------------------------------------------------
 332  */
 333 Oid
 334 DefineRelation(CreateStmt *stmt, char relkind)
 335 {
 336         char            relname[NAMEDATALEN];
 337         Oid                     namespaceId;
 338         List       *schema = stmt->tableElts;
 339         Oid                     relationId;
 340         Oid                     tablespaceId;
 341         Relation        rel;
 342         TupleDesc       descriptor;
 343         List       *inheritOids;
 344         List       *old_constraints;
 345         bool            localHasOids;
 346         int                     parentOidCount;
 347         List       *rawDefaults;
 348         List       *cookedDefaults;
 349         Datum           reloptions;
 350         ListCell   *listptr;
 351         AttrNumber      attnum;
 352
 353         /*
 354          * Truncate relname to appropriate length (probably a waste of time, as
 355          * parser should have done this already).
 356          */
 357         StrNCpy(relname, stmt->relation->relname, NAMEDATALEN);
 358
 359         /*
 360          * Check consistency of arguments
 361          */
 362         if (stmt->oncommit != ONCOMMIT_NOOP && !stmt->relation->istemp)
 363                 ereport(ERROR,
 364                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 365                                  errmsg("ON COMMIT can only be used on temporary tables")));
 366
 367         /*
 368          * Look up the namespace in which we are supposed to create the relation.
 369          * Check we have permission to create there. Skip check if bootstrapping,
 370          * since permissions machinery may not be working yet.
 371          */
 372         namespaceId = RangeVarGetCreationNamespace(stmt->relation);
 373
 374         if (!IsBootstrapProcessingMode())
 375         {
 376                 AclResult       aclresult;
 377
 378                 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
 379                                                                                   ACL_CREATE);
 380                 if (aclresult != ACLCHECK_OK)
 381                         aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
 382                                                    get_namespace_name(namespaceId));
 383         }
 384
 385         /*
 386          * Select tablespace to use.  If not specified, use default tablespace
 387          * (which may in turn default to database's default).
 388          */
 389         if (stmt->tablespacename)
 390         {
 391                 tablespaceId = get_tablespace_oid(stmt->tablespacename);
 392                 if (!OidIsValid(tablespaceId))
 393                         ereport(ERROR,
 394                                         (errcode(ERRCODE_UNDEFINED_OBJECT),
 395                                          errmsg("tablespace \"%s\" does not exist",
 396                                                         stmt->tablespacename)));
 397         }
 398         else
 399         {
 400                 tablespaceId = GetDefaultTablespace(stmt->relation->istemp);
 401                 /* note InvalidOid is OK in this case */
 402         }
 403
 404         /* Check permissions except when using database's default */
 405         if (OidIsValid(tablespaceId) && tablespaceId != MyDatabaseTableSpace)
 406         {
 407                 AclResult       aclresult;
 408
 409                 aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(),
 410                                                                                    ACL_CREATE);
 411                 if (aclresult != ACLCHECK_OK)
 412                         aclcheck_error(aclresult, ACL_KIND_TABLESPACE,
 413                                                    get_tablespace_name(tablespaceId));
 414         }
 415
 416         /*
 417          * Parse and validate reloptions, if any.
 418          */
 419         reloptions = transformRelOptions((Datum) 0, stmt->options, true, false);
 420
 421         (void) heap_reloptions(relkind, reloptions, true);
 422
 423         /*
 424          * Look up inheritance ancestors and generate relation schema, including
 425          * inherited attributes.
 426          */
 427         schema = MergeAttributes(schema, stmt->inhRelations,
 428                                                          stmt->relation->istemp,
 429                                                          &inheritOids, &old_constraints, &parentOidCount);
 430
 431         /*
 432          * Create a tuple descriptor from the relation schema.  Note that this
 433          * deals with column names, types, and NOT NULL constraints, but not
 434          * default values or CHECK constraints; we handle those below.
 435          */
 436         descriptor = BuildDescForRelation(schema);
 437
 438         localHasOids = interpretOidsOption(stmt->options);
 439         descriptor->tdhasoid = (localHasOids || parentOidCount > 0);
 440
 441         /*
 442          * Find columns with default values and prepare for insertion of the
 443          * defaults.  Pre-cooked (that is, inherited) defaults go into a list of
 444          * CookedConstraint structs that we'll pass to heap_create_with_catalog,
 445          * while raw defaults go into a list of RawColumnDefault structs that
 446          * will be processed by AddRelationNewConstraints.  (We can't deal with
 447          * raw expressions until we can do transformExpr.)
 448          *
 449          * We can set the atthasdef flags now in the tuple descriptor; this just
 450          * saves StoreAttrDefault from having to do an immediate update of the
 451          * pg_attribute rows.
 452          */
 453         rawDefaults = NIL;
 454         cookedDefaults = NIL;
 455         attnum = 0;
 456
 457         foreach(listptr, schema)
 458         {
 459                 ColumnDef  *colDef = lfirst(listptr);
 460
 461                 attnum++;
 462
 463                 if (colDef->raw_default != NULL)
 464                 {
 465                         RawColumnDefault *rawEnt;
 466
 467                         Assert(colDef->cooked_default == NULL);
 468
 469                         rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
 470                         rawEnt->attnum = attnum;
 471                         rawEnt->raw_default = colDef->raw_default;
 472                         rawDefaults = lappend(rawDefaults, rawEnt);
 473                         descriptor->attrs[attnum - 1]->atthasdef = true;
 474                 }
 475                 else if (colDef->cooked_default != NULL)
 476                 {
 477                         CookedConstraint *cooked;
 478
 479                         cooked = (CookedConstraint *) palloc(sizeof(CookedConstraint));
 480                         cooked->contype = CONSTR_DEFAULT;
 481                         cooked->name = NULL;
 482                         cooked->attnum = attnum;
 483                         cooked->expr = stringToNode(colDef->cooked_default);
 484                         cooked->is_local = true;        /* not used for defaults */
 485                         cooked->inhcount = 0;           /* ditto */
 486                         cookedDefaults = lappend(cookedDefaults, cooked);
 487                         descriptor->attrs[attnum - 1]->atthasdef = true;
 488                 }
 489         }
 490
 491         /*
 492          * Create the relation.  Inherited defaults and constraints are passed
 493          * in for immediate handling --- since they don't need parsing, they
 494          * can be stored immediately.
 495          */
 496         relationId = heap_create_with_catalog(relname,
 497                                                                                   namespaceId,
 498                                                                                   tablespaceId,
 499                                                                                   InvalidOid,
 500                                                                                   GetUserId(),
 501                                                                                   descriptor,
 502                                                                                   list_concat(cookedDefaults,
 503                                                                                                           old_constraints),
 504                                                                                   relkind,
 505                                                                                   false,
 506                                                                                   localHasOids,
 507                                                                                   parentOidCount,
 508                                                                                   stmt->oncommit,
 509                                                                                   reloptions,
 510                                                                                   allowSystemTableMods);
 511
 512         StoreCatalogInheritance(relationId, inheritOids);
 513
 514         /*
 515          * We must bump the command counter to make the newly-created relation
 516          * tuple visible for opening.
 517          */
 518         CommandCounterIncrement();
 519
 520         /*
 521          * Open the new relation and acquire exclusive lock on it.      This isn't
 522          * really necessary for locking out other backends (since they can't see
 523          * the new rel anyway until we commit), but it keeps the lock manager from
 524          * complaining about deadlock risks.
 525          */
 526         rel = relation_open(relationId, AccessExclusiveLock);
 527
 528         /*
 529          * Now add any newly specified column default values and CHECK constraints
 530          * to the new relation.  These are passed to us in the form of raw
 531          * parsetrees; we need to transform them to executable expression trees
 532          * before they can be added. The most convenient way to do that is to
 533          * apply the parser's transformExpr routine, but transformExpr doesn't
 534          * work unless we have a pre-existing relation. So, the transformation has
 535          * to be postponed to this final step of CREATE TABLE.
 536          */
 537         if (rawDefaults || stmt->constraints)
 538                 AddRelationNewConstraints(rel, rawDefaults, stmt->constraints,
 539                                                                   true, true);
 540
 541         /*
 542          * Clean up.  We keep lock on new relation (although it shouldn't be
 543          * visible to anyone else anyway, until commit).
 544          */
 545         relation_close(rel, NoLock);
 546
 547         return relationId;
 548 }
 549
 550 /*
 551  * Emit the right error or warning message for a "DROP" command issued on a
 552  * non-existent relation
 553  */
 554 static void
 555 DropErrorMsgNonExistent(const char *relname, char rightkind, bool missing_ok)
 556 {
 557         const struct dropmsgstrings *rentry;
 558
 559         for (rentry = dropmsgstringarray; rentry->kind != '\0'; rentry++)
 560         {
 561                 if (rentry->kind == rightkind)
 562                 {
 563                         if (!missing_ok)
 564                         {
 565                                 ereport(ERROR,
 566                                                 (errcode(rentry->nonexistent_code),
 567                                                  errmsg(rentry->nonexistent_msg, relname)));
 568                         }
 569                         else
 570                         {
 571                                 ereport(NOTICE, (errmsg(rentry->skipping_msg, relname)));
 572                                 break;
 573                         }
 574                 }
 575         }
 576
 577         Assert(rentry->kind != '\0');           /* Should be impossible */
 578 }
 579
 580 /*
 581  * Emit the right error message for a "DROP" command issued on a
 582  * relation of the wrong type
 583  */
 584 static void
 585 DropErrorMsgWrongType(const char *relname, char wrongkind, char rightkind)
 586 {
 587         const struct dropmsgstrings *rentry;
 588         const struct dropmsgstrings *wentry;
 589
 590         for (rentry = dropmsgstringarray; rentry->kind != '\0'; rentry++)
 591                 if (rentry->kind == rightkind)
 592                         break;
 593         Assert(rentry->kind != '\0');
 594
 595         for (wentry = dropmsgstringarray; wentry->kind != '\0'; wentry++)
 596                 if (wentry->kind == wrongkind)
 597                         break;
 598         /* wrongkind could be something we don't have in our table... */
 599
 600         ereport(ERROR,
 601                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 602                          errmsg(rentry->nota_msg, relname),
 603                          (wentry->kind != '\0') ? errhint(wentry->drophint_msg) : 0));
 604 }
 605
 606 /*
 607  * RemoveRelations
 608  *              Implements DROP TABLE, DROP INDEX, DROP SEQUENCE, DROP VIEW
 609  */
 610 void
 611 RemoveRelations(DropStmt *drop)
 612 {
 613         ObjectAddresses *objects;
 614         char            relkind;
 615         ListCell   *cell;
 616
 617         /*
 618          * First we identify all the relations, then we delete them in a single
 619          * performMultipleDeletions() call.  This is to avoid unwanted
 620          * DROP RESTRICT errors if one of the relations depends on another.
 621          */
 622
 623         /* Determine required relkind */
 624         switch (drop->removeType)
 625         {
 626                 case OBJECT_TABLE:
 627                         relkind = RELKIND_RELATION;
 628                         break;
 629
 630                 case OBJECT_INDEX:
 631                         relkind = RELKIND_INDEX;
 632                         break;
 633
 634                 case OBJECT_SEQUENCE:
 635                         relkind = RELKIND_SEQUENCE;
 636                         break;
 637
 638                 case OBJECT_VIEW:
 639                         relkind = RELKIND_VIEW;
 640                         break;
 641
 642                 default:
 643                         elog(ERROR, "unrecognized drop object type: %d",
 644                                  (int) drop->removeType);
 645                         relkind = 0;    /* keep compiler quiet */
 646                         break;
 647         }
 648
 649         /* Lock and validate each relation; build a list of object addresses */
 650         objects = new_object_addresses();
 651
 652         foreach(cell, drop->objects)
 653         {
 654                 RangeVar   *rel = makeRangeVarFromNameList((List *) lfirst(cell));
 655                 Oid                     relOid;
 656                 HeapTuple       tuple;
 657                 Form_pg_class classform;
 658                 ObjectAddress obj;
 659
 660                 /*
 661                  * These next few steps are a great deal like relation_openrv, but we
 662                  * don't bother building a relcache entry since we don't need it.
 663                  *
 664                  * Check for shared-cache-inval messages before trying to access the
 665                  * relation.  This is needed to cover the case where the name
 666                  * identifies a rel that has been dropped and recreated since the
 667                  * start of our transaction: if we don't flush the old syscache entry,
 668                  * then we'll latch onto that entry and suffer an error later.
 669                  */
 670                 AcceptInvalidationMessages();
 671
 672                 /* Look up the appropriate relation using namespace search */
 673                 relOid = RangeVarGetRelid(rel, true);
 674
 675                 /* Not there? */
 676                 if (!OidIsValid(relOid))
 677                 {
 678                         DropErrorMsgNonExistent(rel->relname, relkind, drop->missing_ok);
 679                         continue;
 680                 }
 681
 682                 /*
 683                  * In DROP INDEX, attempt to acquire lock on the parent table before
 684                  * locking the index.  index_drop() will need this anyway, and since
 685                  * regular queries lock tables before their indexes, we risk deadlock
 686                  * if we do it the other way around.  No error if we don't find a
 687                  * pg_index entry, though --- that most likely means it isn't an
 688                  * index, and we'll fail below.
 689                  */
 690                 if (relkind == RELKIND_INDEX)
 691                 {
 692                         tuple = SearchSysCache(INDEXRELID,
 693                                                                    ObjectIdGetDatum(relOid),
 694                                                                    0, 0, 0);
 695                         if (HeapTupleIsValid(tuple))
 696                         {
 697                                 Form_pg_index index = (Form_pg_index) GETSTRUCT(tuple);
 698
 699                                 LockRelationOid(index->indrelid, AccessExclusiveLock);
 700                                 ReleaseSysCache(tuple);
 701                         }
 702                 }
 703
 704                 /* Get the lock before trying to fetch the syscache entry */
 705                 LockRelationOid(relOid, AccessExclusiveLock);
 706
 707                 tuple = SearchSysCache(RELOID,
 708                                                            ObjectIdGetDatum(relOid),
 709                                                            0, 0, 0);
 710                 if (!HeapTupleIsValid(tuple))
 711                         elog(ERROR, "cache lookup failed for relation %u", relOid);
 712                 classform = (Form_pg_class) GETSTRUCT(tuple);
 713
 714                 if (classform->relkind != relkind)
 715                         DropErrorMsgWrongType(rel->relname, classform->relkind, relkind);
 716
 717                 /* Allow DROP to either table owner or schema owner */
 718                 if (!pg_class_ownercheck(relOid, GetUserId()) &&
 719                         !pg_namespace_ownercheck(classform->relnamespace, GetUserId()))
 720                         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
 721                                                    rel->relname);
 722
 723                 if (!allowSystemTableMods && IsSystemClass(classform))
 724                         ereport(ERROR,
 725                                         (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 726                                          errmsg("permission denied: \"%s\" is a system catalog",
 727                                                         rel->relname)));
 728
 729                 /* OK, we're ready to delete this one */
 730                 obj.classId = RelationRelationId;
 731                 obj.objectId = relOid;
 732                 obj.objectSubId = 0;
 733
 734                 add_exact_object_address(&obj, objects);
 735
 736                 ReleaseSysCache(tuple);
 737         }
 738
 739         performMultipleDeletions(objects, drop->behavior);
 740
 741         free_object_addresses(objects);
 742 }
 743
 744 /*
 745  * ExecuteTruncate
 746  *              Executes a TRUNCATE command.
 747  *
 748  * This is a multi-relation truncate.  We first open and grab exclusive
 749  * lock on all relations involved, checking permissions and otherwise
 750  * verifying that the relation is OK for truncation.  In CASCADE mode,
 751  * relations having FK references to the targeted relations are automatically
 752  * added to the group; in RESTRICT mode, we check that all FK references are
 753  * internal to the group that's being truncated.  Finally all the relations
 754  * are truncated and reindexed.
 755  */
 756 void
 757 ExecuteTruncate(TruncateStmt *stmt)
 758 {
 759         List       *rels = NIL;
 760         List       *relids = NIL;
 761         List       *seq_relids = NIL;
 762         EState     *estate;
 763         ResultRelInfo *resultRelInfos;
 764         ResultRelInfo *resultRelInfo;
 765         ListCell   *cell;
 766
 767         /*
 768          * Open, exclusive-lock, and check all the explicitly-specified relations
 769          */
 770         foreach(cell, stmt->relations)
 771         {
 772                 RangeVar   *rv = lfirst(cell);
 773                 Relation        rel;
 774
 775                 rel = heap_openrv(rv, AccessExclusiveLock);
 776                 /* don't throw error for "TRUNCATE foo, foo" */
 777                 if (list_member_oid(relids, RelationGetRelid(rel)))
 778                 {
 779                         heap_close(rel, AccessExclusiveLock);
 780                         continue;
 781                 }
 782                 truncate_check_rel(rel);
 783                 rels = lappend(rels, rel);
 784                 relids = lappend_oid(relids, RelationGetRelid(rel));
 785         }
 786
 787         /*
 788          * In CASCADE mode, suck in all referencing relations as well.  This
 789          * requires multiple iterations to find indirectly-dependent relations. At
 790          * each phase, we need to exclusive-lock new rels before looking for their
 791          * dependencies, else we might miss something.  Also, we check each rel as
 792          * soon as we open it, to avoid a faux pas such as holding lock for a long
 793          * time on a rel we have no permissions for.
 794          */
 795         if (stmt->behavior == DROP_CASCADE)
 796         {
 797                 for (;;)
 798                 {
 799                         List       *newrelids;
 800
 801                         newrelids = heap_truncate_find_FKs(relids);
 802                         if (newrelids == NIL)
 803                                 break;                  /* nothing else to add */
 804
 805                         foreach(cell, newrelids)
 806                         {
 807                                 Oid                     relid = lfirst_oid(cell);
 808                                 Relation        rel;
 809
 810                                 rel = heap_open(relid, AccessExclusiveLock);
 811                                 ereport(NOTICE,
 812                                                 (errmsg("truncate cascades to table \"%s\"",
 813                                                                 RelationGetRelationName(rel))));
 814                                 truncate_check_rel(rel);
 815                                 rels = lappend(rels, rel);
 816                                 relids = lappend_oid(relids, relid);
 817                         }
 818                 }
 819         }
 820
 821         /*
 822          * Check foreign key references.  In CASCADE mode, this should be
 823          * unnecessary since we just pulled in all the references; but as a
 824          * cross-check, do it anyway if in an Assert-enabled build.
 825          */
 826 #ifdef USE_ASSERT_CHECKING
 827         heap_truncate_check_FKs(rels, false);
 828 #else
 829         if (stmt->behavior == DROP_RESTRICT)
 830                 heap_truncate_check_FKs(rels, false);
 831 #endif
 832
 833         /*
 834          * If we are asked to restart sequences, find all the sequences,
 835          * lock them (we only need AccessShareLock because that's all that
 836          * ALTER SEQUENCE takes), and check permissions.  We want to do this
 837          * early since it's pointless to do all the truncation work only to fail
 838          * on sequence permissions.
 839          */
 840         if (stmt->restart_seqs)
 841         {
 842                 foreach(cell, rels)
 843                 {
 844                         Relation        rel = (Relation) lfirst(cell);
 845                         List       *seqlist = getOwnedSequences(RelationGetRelid(rel));
 846                         ListCell   *seqcell;
 847
 848                         foreach(seqcell, seqlist)
 849                         {
 850                                 Oid             seq_relid = lfirst_oid(seqcell);
 851                                 Relation seq_rel;
 852
 853                                 seq_rel = relation_open(seq_relid, AccessShareLock);
 854
 855                                 /* This check must match AlterSequence! */
 856                                 if (!pg_class_ownercheck(seq_relid, GetUserId()))
 857                                         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
 858                                                                    RelationGetRelationName(seq_rel));
 859
 860                                 seq_relids = lappend_oid(seq_relids, seq_relid);
 861
 862                                 relation_close(seq_rel, NoLock);
 863                         }
 864                 }
 865         }
 866
 867         /* Prepare to catch AFTER triggers. */
 868         AfterTriggerBeginQuery();
 869
 870         /*
 871          * To fire triggers, we'll need an EState as well as a ResultRelInfo
 872          * for each relation.
 873          */
 874         estate = CreateExecutorState();
 875         resultRelInfos = (ResultRelInfo *)
 876                 palloc(list_length(rels) * sizeof(ResultRelInfo));
 877         resultRelInfo = resultRelInfos;
 878         foreach(cell, rels)
 879         {
 880                 Relation        rel = (Relation) lfirst(cell);
 881
 882                 InitResultRelInfo(resultRelInfo,
 883                                                   rel,
 884                                                   0,                    /* dummy rangetable index */
 885                                                   CMD_DELETE,   /* don't need any index info */
 886                                                   false);
 887                 resultRelInfo++;
 888         }
 889         estate->es_result_relations = resultRelInfos;
 890         estate->es_num_result_relations = list_length(rels);
 891
 892         /*
 893          * Process all BEFORE STATEMENT TRUNCATE triggers before we begin
 894          * truncating (this is because one of them might throw an error).
 895          * Also, if we were to allow them to prevent statement execution,
 896          * that would need to be handled here.
 897          */
 898         resultRelInfo = resultRelInfos;
 899         foreach(cell, rels)
 900         {
 901                 estate->es_result_relation_info = resultRelInfo;
 902                 ExecBSTruncateTriggers(estate, resultRelInfo);
 903                 resultRelInfo++;
 904         }
 905
 906         /*
 907          * OK, truncate each table.
 908          */
 909         foreach(cell, rels)
 910         {
 911                 Relation        rel = (Relation) lfirst(cell);
 912                 Oid                     heap_relid;
 913                 Oid                     toast_relid;
 914
 915                 /*
 916                  * Create a new empty storage file for the relation, and assign it as
 917                  * the relfilenode value.       The old storage file is scheduled for
 918                  * deletion at commit.
 919                  */
 920                 setNewRelfilenode(rel, RecentXmin);
 921
 922                 heap_relid = RelationGetRelid(rel);
 923                 toast_relid = rel->rd_rel->reltoastrelid;
 924
 925                 /*
 926                  * The same for the toast table, if any.
 927                  */
 928                 if (OidIsValid(toast_relid))
 929                 {
 930                         rel = relation_open(toast_relid, AccessExclusiveLock);
 931                         setNewRelfilenode(rel, RecentXmin);
 932                         heap_close(rel, NoLock);
 933                 }
 934
 935                 /*
 936                  * Reconstruct the indexes to match, and we're done.
 937                  */
 938                 reindex_relation(heap_relid, true);
 939         }
 940
 941         /*
 942          * Process all AFTER STATEMENT TRUNCATE triggers.
 943          */
 944         resultRelInfo = resultRelInfos;
 945         foreach(cell, rels)
 946         {
 947                 estate->es_result_relation_info = resultRelInfo;
 948                 ExecASTruncateTriggers(estate, resultRelInfo);
 949                 resultRelInfo++;
 950         }
 951
 952         /* Handle queued AFTER triggers */
 953         AfterTriggerEndQuery(estate);
 954
 955         /* We can clean up the EState now */
 956         FreeExecutorState(estate);
 957
 958         /* And close the rels (can't do this while EState still holds refs) */
 959         foreach(cell, rels)
 960         {
 961                 Relation        rel = (Relation) lfirst(cell);
 962
 963                 heap_close(rel, NoLock);
 964         }
 965
 966         /*
 967          * Lastly, restart any owned sequences if we were asked to.  This is done
 968          * last because it's nontransactional: restarts will not roll back if
 969          * we abort later.  Hence it's important to postpone them as long as
 970          * possible.  (This is also a big reason why we locked and
 971          * permission-checked the sequences beforehand.)
 972          */
 973         if (stmt->restart_seqs)
 974         {
 975                 List   *options = list_make1(makeDefElem("restart", NULL));
 976
 977                 foreach(cell, seq_relids)
 978                 {
 979                         Oid             seq_relid = lfirst_oid(cell);
 980
 981                         AlterSequenceInternal(seq_relid, options);
 982                 }
 983         }
 984 }
 985
 986 /*
 987  * Check that a given rel is safe to truncate.  Subroutine for ExecuteTruncate
 988  */
 989 static void
 990 truncate_check_rel(Relation rel)
 991 {
 992         AclResult       aclresult;
 993
 994         /* Only allow truncate on regular tables */
 995         if (rel->rd_rel->relkind != RELKIND_RELATION)
 996                 ereport(ERROR,
 997                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 998                                  errmsg("\"%s\" is not a table",
 999                                                 RelationGetRelationName(rel))));
1000
1001         /* Permissions checks */
1002         aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
1003                                                                   ACL_TRUNCATE);
1004         if (aclresult != ACLCHECK_OK)
1005                 aclcheck_error(aclresult, ACL_KIND_CLASS,
1006                                            RelationGetRelationName(rel));
1007
1008         if (!allowSystemTableMods && IsSystemRelation(rel))
1009                 ereport(ERROR,
1010                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
1011                                  errmsg("permission denied: \"%s\" is a system catalog",
1012                                                 RelationGetRelationName(rel))));
1013
1014         /*
1015          * We can never allow truncation of shared or nailed-in-cache relations,
1016          * because we can't support changing their relfilenode values.
1017          */
1018         if (rel->rd_rel->relisshared || rel->rd_isnailed)
1019                 ereport(ERROR,
1020                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1021                                  errmsg("cannot truncate system relation \"%s\"",
1022                                                 RelationGetRelationName(rel))));
1023
1024         /*
1025          * Don't allow truncate on temp tables of other backends ... their local
1026          * buffer manager is not going to cope.
1027          */
1028         if (isOtherTempNamespace(RelationGetNamespace(rel)))
1029                 ereport(ERROR,
1030                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1031                           errmsg("cannot truncate temporary tables of other sessions")));
1032
1033         /*
1034          * Also check for active uses of the relation in the current transaction,
1035          * including open scans and pending AFTER trigger events.
1036          */
1037         CheckTableNotInUse(rel, "TRUNCATE");
1038 }
1039
1040 /*----------
1041  * MergeAttributes
1042  *              Returns new schema given initial schema and superclasses.
1043  *
1044  * Input arguments:
1045  * 'schema' is the column/attribute definition for the table. (It's a list
1046  *              of ColumnDef's.) It is destructively changed.
1047  * 'supers' is a list of names (as RangeVar nodes) of parent relations.
1048  * 'istemp' is TRUE if we are creating a temp relation.
1049  *
1050  * Output arguments:
1051  * 'supOids' receives a list of the OIDs of the parent relations.
1052  * 'supconstr' receives a list of constraints belonging to the parents,
1053  *              updated as necessary to be valid for the child.
1054  * 'supOidCount' is set to the number of parents that have OID columns.
1055  *
1056  * Return value:
1057  * Completed schema list.
1058  *
1059  * Notes:
1060  *        The order in which the attributes are inherited is very important.
1061  *        Intuitively, the inherited attributes should come first. If a table
1062  *        inherits from multiple parents, the order of those attributes are
1063  *        according to the order of the parents specified in CREATE TABLE.
1064  *
1065  *        Here's an example:
1066  *
1067  *              create table person (name text, age int4, location point);
1068  *              create table emp (salary int4, manager text) inherits(person);
1069  *              create table student (gpa float8) inherits (person);
1070  *              create table stud_emp (percent int4) inherits (emp, student);
1071  *
1072  *        The order of the attributes of stud_emp is:
1073  *
1074  *                                                      person {1:name, 2:age, 3:location}
1075  *                                                      /        \
1076  *                         {6:gpa}      student   emp {4:salary, 5:manager}
1077  *                                                      \        /
1078  *                                                 stud_emp {7:percent}
1079  *
1080  *         If the same attribute name appears multiple times, then it appears
1081  *         in the result table in the proper location for its first appearance.
1082  *
1083  *         Constraints (including NOT NULL constraints) for the child table
1084  *         are the union of all relevant constraints, from both the child schema
1085  *         and parent tables.
1086  *
1087  *         The default value for a child column is defined as:
1088  *              (1) If the child schema specifies a default, that value is used.
1089  *              (2) If neither the child nor any parent specifies a default, then
1090  *                      the column will not have a default.
1091  *              (3) If conflicting defaults are inherited from different parents
1092  *                      (and not overridden by the child), an error is raised.
1093  *              (4) Otherwise the inherited default is used.
1094  *              Rule (3) is new in Postgres 7.1; in earlier releases you got a
1095  *              rather arbitrary choice of which parent default to use.
1096  *----------
1097  */
1098 static List *
1099 MergeAttributes(List *schema, List *supers, bool istemp,
1100                                 List **supOids, List **supconstr, int *supOidCount)
1101 {
1102         ListCell   *entry;
1103         List       *inhSchema = NIL;
1104         List       *parentOids = NIL;
1105         List       *constraints = NIL;
1106         int                     parentsWithOids = 0;
1107         bool            have_bogus_defaults = false;
1108         char       *bogus_marker = "Bogus!";            /* marks conflicting defaults */
1109         int                     child_attno;
1110
1111         /*
1112          * Check for and reject tables with too many columns. We perform this
1113          * check relatively early for two reasons: (a) we don't run the risk of
1114          * overflowing an AttrNumber in subsequent code (b) an O(n^2) algorithm is
1115          * okay if we're processing <= 1600 columns, but could take minutes to
1116          * execute if the user attempts to create a table with hundreds of
1117          * thousands of columns.
1118          *
1119          * Note that we also need to check that any we do not exceed this figure
1120          * after including columns from inherited relations.
1121          */
1122         if (list_length(schema) > MaxHeapAttributeNumber)
1123                 ereport(ERROR,
1124                                 (errcode(ERRCODE_TOO_MANY_COLUMNS),
1125                                  errmsg("tables can have at most %d columns",
1126                                                 MaxHeapAttributeNumber)));
1127
1128         /*
1129          * Check for duplicate names in the explicit list of attributes.
1130          *
1131          * Although we might consider merging such entries in the same way that we
1132          * handle name conflicts for inherited attributes, it seems to make more
1133          * sense to assume such conflicts are errors.
1134          */
1135         foreach(entry, schema)
1136         {
1137                 ColumnDef  *coldef = lfirst(entry);
1138                 ListCell   *rest;
1139
1140                 for_each_cell(rest, lnext(entry))
1141                 {
1142                         ColumnDef  *restdef = lfirst(rest);
1143
1144                         if (strcmp(coldef->colname, restdef->colname) == 0)
1145                                 ereport(ERROR,
1146                                                 (errcode(ERRCODE_DUPLICATE_COLUMN),
1147                                                  errmsg("column \"%s\" specified more than once",
1148                                                                 coldef->colname)));
1149                 }
1150         }
1151
1152         /*
1153          * Scan the parents left-to-right, and merge their attributes to form a
1154          * list of inherited attributes (inhSchema).  Also check to see if we need
1155          * to inherit an OID column.
1156          */
1157         child_attno = 0;
1158         foreach(entry, supers)
1159         {
1160                 RangeVar   *parent = (RangeVar *) lfirst(entry);
1161                 Relation        relation;
1162                 TupleDesc       tupleDesc;
1163                 TupleConstr *constr;
1164                 AttrNumber *newattno;
1165                 AttrNumber      parent_attno;
1166
1167                 relation = heap_openrv(parent, AccessShareLock);
1168
1169                 if (relation->rd_rel->relkind != RELKIND_RELATION)
1170                         ereport(ERROR,
1171                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
1172                                          errmsg("inherited relation \"%s\" is not a table",
1173                                                         parent->relname)));
1174                 /* Permanent rels cannot inherit from temporary ones */
1175                 if (!istemp && isTempNamespace(RelationGetNamespace(relation)))
1176                         ereport(ERROR,
1177                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
1178                                          errmsg("cannot inherit from temporary relation \"%s\"",
1179                                                         parent->relname)));
1180
1181                 /*
1182                  * We should have an UNDER permission flag for this, but for now,
1183                  * demand that creator of a child table own the parent.
1184                  */
1185                 if (!pg_class_ownercheck(RelationGetRelid(relation), GetUserId()))
1186                         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
1187                                                    RelationGetRelationName(relation));
1188
1189                 /*
1190                  * Reject duplications in the list of parents.
1191                  */
1192                 if (list_member_oid(parentOids, RelationGetRelid(relation)))
1193                         ereport(ERROR,
1194                                         (errcode(ERRCODE_DUPLICATE_TABLE),
1195                          errmsg("relation \"%s\" would be inherited from more than once",
1196                                         parent->relname)));
1197
1198                 parentOids = lappend_oid(parentOids, RelationGetRelid(relation));
1199
1200                 if (relation->rd_rel->relhasoids)
1201                         parentsWithOids++;
1202
1203                 tupleDesc = RelationGetDescr(relation);
1204                 constr = tupleDesc->constr;
1205
1206                 /*
1207                  * newattno[] will contain the child-table attribute numbers for the
1208                  * attributes of this parent table.  (They are not the same for
1209                  * parents after the first one, nor if we have dropped columns.)
1210                  */
1211                 newattno = (AttrNumber *)
1212                         palloc(tupleDesc->natts * sizeof(AttrNumber));
1213
1214                 for (parent_attno = 1; parent_attno <= tupleDesc->natts;
1215                          parent_attno++)
1216                 {
1217                         Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1];
1218                         char       *attributeName = NameStr(attribute->attname);
1219                         int                     exist_attno;
1220                         ColumnDef  *def;
1221
1222                         /*
1223                          * Ignore dropped columns in the parent.
1224                          */
1225                         if (attribute->attisdropped)
1226                         {
1227                                 /*
1228                                  * change_varattnos_of_a_node asserts that this is greater
1229                                  * than zero, so if anything tries to use it, we should find
1230                                  * out.
1231                                  */
1232                                 newattno[parent_attno - 1] = 0;
1233                                 continue;
1234                         }
1235
1236                         /*
1237                          * Does it conflict with some previously inherited column?
1238                          */
1239                         exist_attno = findAttrByName(attributeName, inhSchema);
1240                         if (exist_attno > 0)
1241                         {
1242                                 Oid                     defTypeId;
1243                                 int32           deftypmod;
1244
1245                                 /*
1246                                  * Yes, try to merge the two column definitions. They must
1247                                  * have the same type and typmod.
1248                                  */
1249                                 ereport(NOTICE,
1250                                                 (errmsg("merging multiple inherited definitions of column \"%s\"",
1251                                                                 attributeName)));
1252                                 def = (ColumnDef *) list_nth(inhSchema, exist_attno - 1);
1253                                 defTypeId = typenameTypeId(NULL, def->typename, &deftypmod);
1254                                 if (defTypeId != attribute->atttypid ||
1255                                         deftypmod != attribute->atttypmod)
1256                                         ereport(ERROR,
1257                                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
1258                                                 errmsg("inherited column \"%s\" has a type conflict",
1259                                                            attributeName),
1260                                                          errdetail("%s versus %s",
1261                                                                            TypeNameToString(def->typename),
1262                                                                            format_type_be(attribute->atttypid))));
1263                                 def->inhcount++;
1264                                 /* Merge of NOT NULL constraints = OR 'em together */
1265                                 def->is_not_null |= attribute->attnotnull;
1266                                 /* Default and other constraints are handled below */
1267                                 newattno[parent_attno - 1] = exist_attno;
1268                         }
1269                         else
1270                         {
1271                                 /*
1272                                  * No, create a new inherited column
1273                                  */
1274                                 def = makeNode(ColumnDef);
1275                                 def->colname = pstrdup(attributeName);
1276                                 def->typename = makeTypeNameFromOid(attribute->atttypid,
1277                                                                                                         attribute->atttypmod);
1278                                 def->inhcount = 1;
1279                                 def->is_local = false;
1280                                 def->is_not_null = attribute->attnotnull;
1281                                 def->raw_default = NULL;
1282                                 def->cooked_default = NULL;
1283                                 def->constraints = NIL;
1284                                 inhSchema = lappend(inhSchema, def);
1285                                 newattno[parent_attno - 1] = ++child_attno;
1286                         }
1287
1288                         /*
1289                          * Copy default if any
1290                          */
1291                         if (attribute->atthasdef)
1292                         {
1293                                 char       *this_default = NULL;
1294                                 AttrDefault *attrdef;
1295                                 int                     i;
1296
1297                                 /* Find default in constraint structure */
1298                                 Assert(constr != NULL);
1299                                 attrdef = constr->defval;
1300                                 for (i = 0; i < constr->num_defval; i++)
1301                                 {
1302                                         if (attrdef[i].adnum == parent_attno)
1303                                         {
1304                                                 this_default = attrdef[i].adbin;
1305                                                 break;
1306                                         }
1307                                 }
1308                                 Assert(this_default != NULL);
1309
1310                                 /*
1311                                  * If default expr could contain any vars, we'd need to fix
1312                                  * 'em, but it can't; so default is ready to apply to child.
1313                                  *
1314                                  * If we already had a default from some prior parent, check
1315                                  * to see if they are the same.  If so, no problem; if not,
1316                                  * mark the column as having a bogus default. Below, we will
1317                                  * complain if the bogus default isn't overridden by the child
1318                                  * schema.
1319                                  */
1320                                 Assert(def->raw_default == NULL);
1321                                 if (def->cooked_default == NULL)
1322                                         def->cooked_default = pstrdup(this_default);
1323                                 else if (strcmp(def->cooked_default, this_default) != 0)
1324                                 {
1325                                         def->cooked_default = bogus_marker;
1326                                         have_bogus_defaults = true;
1327                                 }
1328                         }
1329                 }
1330
1331                 /*
1332                  * Now copy the CHECK constraints of this parent, adjusting attnos
1333                  * using the completed newattno[] map.  Identically named constraints
1334                  * are merged if possible, else we throw error.
1335                  */
1336                 if (constr && constr->num_check > 0)
1337                 {
1338                         ConstrCheck *check = constr->check;
1339                         int                     i;
1340
1341                         for (i = 0; i < constr->num_check; i++)
1342                         {
1343                                 char       *name = check[i].ccname;
1344                                 Node       *expr;
1345
1346                                 /* adjust varattnos of ccbin here */
1347                                 expr = stringToNode(check[i].ccbin);
1348                                 change_varattnos_of_a_node(expr, newattno);
1349
1350                                 /* check for duplicate */
1351                                 if (!MergeCheckConstraint(constraints, name, expr))
1352                                 {
1353                                         /* nope, this is a new one */
1354                                         CookedConstraint *cooked;
1355
1356                                         cooked = (CookedConstraint *) palloc(sizeof(CookedConstraint));
1357                                         cooked->contype = CONSTR_CHECK;
1358                                         cooked->name = pstrdup(name);
1359                                         cooked->attnum = 0;             /* not used for constraints */
1360                                         cooked->expr = expr;
1361                                         cooked->is_local = false;
1362                                         cooked->inhcount = 1;
1363                                         constraints = lappend(constraints, cooked);
1364                                 }
1365                         }
1366                 }
1367
1368                 pfree(newattno);
1369
1370                 /*
1371                  * Close the parent rel, but keep our AccessShareLock on it until xact
1372                  * commit.      That will prevent someone else from deleting or ALTERing
1373                  * the parent before the child is committed.
1374                  */
1375                 heap_close(relation, NoLock);
1376         }
1377
1378         /*
1379          * If we had no inherited attributes, the result schema is just the
1380          * explicitly declared columns.  Otherwise, we need to merge the declared
1381          * columns into the inherited schema list.
1382          */
1383         if (inhSchema != NIL)
1384         {
1385                 foreach(entry, schema)
1386                 {
1387                         ColumnDef  *newdef = lfirst(entry);
1388                         char       *attributeName = newdef->colname;
1389                         int                     exist_attno;
1390
1391                         /*
1392                          * Does it conflict with some previously inherited column?
1393                          */
1394                         exist_attno = findAttrByName(attributeName, inhSchema);
1395                         if (exist_attno > 0)
1396                         {
1397                                 ColumnDef  *def;
1398                                 Oid                     defTypeId,
1399                                                         newTypeId;
1400                                 int32           deftypmod,
1401                                                         newtypmod;
1402
1403                                 /*
1404                                  * Yes, try to merge the two column definitions. They must
1405                                  * have the same type and typmod.
1406                                  */
1407                                 ereport(NOTICE,
1408                                    (errmsg("merging column \"%s\" with inherited definition",
1409                                                    attributeName)));
1410                                 def = (ColumnDef *) list_nth(inhSchema, exist_attno - 1);
1411                                 defTypeId = typenameTypeId(NULL, def->typename, &deftypmod);
1412                                 newTypeId = typenameTypeId(NULL, newdef->typename, &newtypmod);
1413                                 if (defTypeId != newTypeId || deftypmod != newtypmod)
1414                                         ereport(ERROR,
1415                                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
1416                                                          errmsg("column \"%s\" has a type conflict",
1417                                                                         attributeName),
1418                                                          errdetail("%s versus %s",
1419                                                                            TypeNameToString(def->typename),
1420                                                                            TypeNameToString(newdef->typename))));
1421                                 /* Mark the column as locally defined */
1422                                 def->is_local = true;
1423                                 /* Merge of NOT NULL constraints = OR 'em together */
1424                                 def->is_not_null |= newdef->is_not_null;
1425                                 /* If new def has a default, override previous default */
1426                                 if (newdef->raw_default != NULL)
1427                                 {
1428                                         def->raw_default = newdef->raw_default;
1429                                         def->cooked_default = newdef->cooked_default;
1430                                 }
1431                         }
1432                         else
1433                         {
1434                                 /*
1435                                  * No, attach new column to result schema
1436                                  */
1437                                 inhSchema = lappend(inhSchema, newdef);
1438                         }
1439                 }
1440
1441                 schema = inhSchema;
1442
1443                 /*
1444                  * Check that we haven't exceeded the legal # of columns after merging
1445                  * in inherited columns.
1446                  */
1447                 if (list_length(schema) > MaxHeapAttributeNumber)
1448                         ereport(ERROR,
1449                                         (errcode(ERRCODE_TOO_MANY_COLUMNS),
1450                                          errmsg("tables can have at most %d columns",
1451                                                         MaxHeapAttributeNumber)));
1452         }
1453
1454         /*
1455          * If we found any conflicting parent default values, check to make sure
1456          * they were overridden by the child.
1457          */
1458         if (have_bogus_defaults)
1459         {
1460                 foreach(entry, schema)
1461                 {
1462                         ColumnDef  *def = lfirst(entry);
1463
1464                         if (def->cooked_default == bogus_marker)
1465                                 ereport(ERROR,
1466                                                 (errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
1467                                   errmsg("column \"%s\" inherits conflicting default values",
1468                                                  def->colname),
1469                                                  errhint("To resolve the conflict, specify a default explicitly.")));
1470                 }
1471         }
1472
1473         *supOids = parentOids;
1474         *supconstr = constraints;
1475         *supOidCount = parentsWithOids;
1476         return schema;
1477 }
1478
1479
1480 /*
1481  * MergeCheckConstraint
1482  *              Try to merge an inherited CHECK constraint with previous ones
1483  *
1484  * If we inherit identically-named constraints from multiple parents, we must
1485  * merge them, or throw an error if they don't have identical definitions.
1486  *
1487  * constraints is a list of CookedConstraint structs for previous constraints.
1488  *
1489  * Returns TRUE if merged (constraint is a duplicate), or FALSE if it's
1490  * got a so-far-unique name, or throws error if conflict.
1491  */
1492 static bool
1493 MergeCheckConstraint(List *constraints, char *name, Node *expr)
1494 {
1495         ListCell   *lc;
1496
1497         foreach(lc, constraints)
1498         {
1499                 CookedConstraint *ccon = (CookedConstraint *) lfirst(lc);
1500
1501                 Assert(ccon->contype == CONSTR_CHECK);
1502
1503                 /* Non-matching names never conflict */
1504                 if (strcmp(ccon->name, name) != 0)
1505                         continue;
1506
1507                 if (equal(expr, ccon->expr))
1508                 {
1509                         /* OK to merge */
1510                         ccon->inhcount++;
1511                         return true;
1512                 }
1513
1514                 ereport(ERROR,
1515                                 (errcode(ERRCODE_DUPLICATE_OBJECT),
1516                                  errmsg("check constraint name \"%s\" appears multiple times but with different expressions",
1517                                                 name)));
1518         }
1519
1520         return false;
1521 }
1522
1523
1524 /*
1525  * Replace varattno values in an expression tree according to the given
1526  * map array, that is, varattno N is replaced by newattno[N-1].  It is
1527  * caller's responsibility to ensure that the array is long enough to
1528  * define values for all user varattnos present in the tree.  System column
1529  * attnos remain unchanged.
1530  *
1531  * Note that the passed node tree is modified in-place!
1532  */
1533 void
1534 change_varattnos_of_a_node(Node *node, const AttrNumber *newattno)
1535 {
1536         /* no setup needed, so away we go */
1537         (void) change_varattnos_walker(node, newattno);
1538 }
1539
1540 static bool
1541 change_varattnos_walker(Node *node, const AttrNumber *newattno)
1542 {
1543         if (node == NULL)
1544                 return false;
1545         if (IsA(node, Var))
1546         {
1547                 Var                *var = (Var *) node;
1548
1549                 if (var->varlevelsup == 0 && var->varno == 1 &&
1550                         var->varattno > 0)
1551                 {
1552                         /*
1553                          * ??? the following may be a problem when the node is multiply
1554                          * referenced though stringToNode() doesn't create such a node
1555                          * currently.
1556                          */
1557                         Assert(newattno[var->varattno - 1] > 0);
1558                         var->varattno = var->varoattno = newattno[var->varattno - 1];
1559                 }
1560                 return false;
1561         }
1562         return expression_tree_walker(node, change_varattnos_walker,
1563                                                                   (void *) newattno);
1564 }
1565
1566 /*
1567  * Generate a map for change_varattnos_of_a_node from old and new TupleDesc's,
1568  * matching according to column name.
1569  */
1570 AttrNumber *
1571 varattnos_map(TupleDesc old, TupleDesc new)
1572 {
1573         AttrNumber *attmap;
1574         int                     i,
1575                                 j;
1576
1577         attmap = (AttrNumber *) palloc0(sizeof(AttrNumber) * old->natts);
1578         for (i = 1; i <= old->natts; i++)
1579         {
1580                 if (old->attrs[i - 1]->attisdropped)
1581                         continue;                       /* leave the entry as zero */
1582
1583                 for (j = 1; j <= new->natts; j++)
1584                 {
1585                         if (strcmp(NameStr(old->attrs[i - 1]->attname),
1586                                            NameStr(new->attrs[j - 1]->attname)) == 0)
1587                         {
1588                                 attmap[i - 1] = j;
1589                                 break;
1590                         }
1591                 }
1592         }
1593         return attmap;
1594 }
1595
1596 /*
1597  * Generate a map for change_varattnos_of_a_node from a TupleDesc and a list
1598  * of ColumnDefs
1599  */
1600 AttrNumber *
1601 varattnos_map_schema(TupleDesc old, List *schema)
1602 {
1603         AttrNumber *attmap;
1604         int                     i;
1605
1606         attmap = (AttrNumber *) palloc0(sizeof(AttrNumber) * old->natts);
1607         for (i = 1; i <= old->natts; i++)
1608         {
1609                 if (old->attrs[i - 1]->attisdropped)
1610                         continue;                       /* leave the entry as zero */
1611
1612                 attmap[i - 1] = findAttrByName(NameStr(old->attrs[i - 1]->attname),
1613                                                                            schema);
1614         }
1615         return attmap;
1616 }
1617
1618
1619 /*
1620  * StoreCatalogInheritance
1621  *              Updates the system catalogs with proper inheritance information.
1622  *
1623  * supers is a list of the OIDs of the new relation's direct ancestors.
1624  */
1625 static void
1626 StoreCatalogInheritance(Oid relationId, List *supers)
1627 {
1628         Relation        relation;
1629         int16           seqNumber;
1630         ListCell   *entry;
1631
1632         /*
1633          * sanity checks
1634          */
1635         AssertArg(OidIsValid(relationId));
1636
1637         if (supers == NIL)
1638                 return;
1639
1640         /*
1641          * Store INHERITS information in pg_inherits using direct ancestors only.
1642          * Also enter dependencies on the direct ancestors, and make sure they are
1643          * marked with relhassubclass = true.
1644          *
1645          * (Once upon a time, both direct and indirect ancestors were found here
1646          * and then entered into pg_ipl.  Since that catalog doesn't exist
1647          * anymore, there's no need to look for indirect ancestors.)
1648          */
1649         relation = heap_open(InheritsRelationId, RowExclusiveLock);
1650
1651         seqNumber = 1;
1652         foreach(entry, supers)
1653         {
1654                 Oid                     parentOid = lfirst_oid(entry);
1655
1656                 StoreCatalogInheritance1(relationId, parentOid, seqNumber, relation);
1657                 seqNumber++;
1658         }
1659
1660         heap_close(relation, RowExclusiveLock);
1661 }
1662
1663 /*
1664  * Make catalog entries showing relationId as being an inheritance child
1665  * of parentOid.  inhRelation is the already-opened pg_inherits catalog.
1666  */
1667 static void
1668 StoreCatalogInheritance1(Oid relationId, Oid parentOid,
1669                                                  int16 seqNumber, Relation inhRelation)
1670 {
1671         TupleDesc       desc = RelationGetDescr(inhRelation);
1672         Datum           datum[Natts_pg_inherits];
1673         bool            nullarr[Natts_pg_inherits];
1674         ObjectAddress childobject,
1675                                 parentobject;
1676         HeapTuple       tuple;
1677
1678         /*
1679          * Make the pg_inherits entry
1680          */
1681         datum[0] = ObjectIdGetDatum(relationId);        /* inhrelid */
1682         datum[1] = ObjectIdGetDatum(parentOid);         /* inhparent */
1683         datum[2] = Int16GetDatum(seqNumber);            /* inhseqno */
1684
1685         nullarr[0] = false;
1686         nullarr[1] = false;
1687         nullarr[2] = false;
1688
1689         tuple = heap_form_tuple(desc, datum, nullarr);
1690
1691         simple_heap_insert(inhRelation, tuple);
1692
1693         CatalogUpdateIndexes(inhRelation, tuple);
1694
1695         heap_freetuple(tuple);
1696
1697         /*
1698          * Store a dependency too
1699          */
1700         parentobject.classId = RelationRelationId;
1701         parentobject.objectId = parentOid;
1702         parentobject.objectSubId = 0;
1703         childobject.classId = RelationRelationId;
1704         childobject.objectId = relationId;
1705         childobject.objectSubId = 0;
1706
1707         recordDependencyOn(&childobject, &parentobject, DEPENDENCY_NORMAL);
1708
1709         /*
1710          * Mark the parent as having subclasses.
1711          */
1712         setRelhassubclassInRelation(parentOid, true);
1713 }
1714
1715 /*
1716  * Look for an existing schema entry with the given name.
1717  *
1718  * Returns the index (starting with 1) if attribute already exists in schema,
1719  * 0 if it doesn't.
1720  */
1721 static int
1722 findAttrByName(const char *attributeName, List *schema)
1723 {
1724         ListCell   *s;
1725         int                     i = 1;
1726
1727         foreach(s, schema)
1728         {
1729                 ColumnDef  *def = lfirst(s);
1730
1731                 if (strcmp(attributeName, def->colname) == 0)
1732                         return i;
1733
1734                 i++;
1735         }
1736         return 0;
1737 }
1738
1739 /*
1740  * Update a relation's pg_class.relhassubclass entry to the given value
1741  */
1742 static void
1743 setRelhassubclassInRelation(Oid relationId, bool relhassubclass)
1744 {
1745         Relation        relationRelation;
1746         HeapTuple       tuple;
1747         Form_pg_class classtuple;
1748
1749         /*
1750          * Fetch a modifiable copy of the tuple, modify it, update pg_class.
1751          *
1752          * If the tuple already has the right relhassubclass setting, we don't
1753          * need to update it, but we still need to issue an SI inval message.
1754          */
1755         relationRelation = heap_open(RelationRelationId, RowExclusiveLock);
1756         tuple = SearchSysCacheCopy(RELOID,
1757                                                            ObjectIdGetDatum(relationId),
1758                                                            0, 0, 0);
1759         if (!HeapTupleIsValid(tuple))
1760                 elog(ERROR, "cache lookup failed for relation %u", relationId);
1761         classtuple = (Form_pg_class) GETSTRUCT(tuple);
1762
1763         if (classtuple->relhassubclass != relhassubclass)
1764         {
1765                 classtuple->relhassubclass = relhassubclass;
1766                 simple_heap_update(relationRelation, &tuple->t_self, tuple);
1767
1768                 /* keep the catalog indexes up to date */
1769                 CatalogUpdateIndexes(relationRelation, tuple);
1770         }
1771         else
1772         {
1773                 /* no need to change tuple, but force relcache rebuild anyway */
1774                 CacheInvalidateRelcacheByTuple(tuple);
1775         }
1776
1777         heap_freetuple(tuple);
1778         heap_close(relationRelation, RowExclusiveLock);
1779 }
1780
1781
1782 /*
1783  *              renameatt               - changes the name of a attribute in a relation
1784  *
1785  *              Attname attribute is changed in attribute catalog.
1786  *              No record of the previous attname is kept (correct?).
1787  *
1788  *              get proper relrelation from relation catalog (if not arg)
1789  *              scan attribute catalog
1790  *                              for name conflict (within rel)
1791  *                              for original attribute (if not arg)
1792  *              modify attname in attribute tuple
1793  *              insert modified attribute in attribute catalog
1794  *              delete original attribute from attribute catalog
1795  */
1796 void
1797 renameatt(Oid myrelid,
1798                   const char *oldattname,
1799                   const char *newattname,
1800                   bool recurse,
1801                   bool recursing)
1802 {
1803         Relation        targetrelation;
1804         Relation        attrelation;
1805         HeapTuple       atttup;
1806         Form_pg_attribute attform;
1807         int                     attnum;
1808         List       *indexoidlist;
1809         ListCell   *indexoidscan;
1810
1811         /*
1812          * Grab an exclusive lock on the target table, which we will NOT release
1813          * until end of transaction.
1814          */
1815         targetrelation = relation_open(myrelid, AccessExclusiveLock);
1816
1817         /*
1818          * permissions checking.  this would normally be done in utility.c, but
1819          * this particular routine is recursive.
1820          *
1821          * normally, only the owner of a class can change its schema.
1822          */
1823         if (!pg_class_ownercheck(myrelid, GetUserId()))
1824                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
1825                                            RelationGetRelationName(targetrelation));
1826         if (!allowSystemTableMods && IsSystemRelation(targetrelation))
1827                 ereport(ERROR,
1828                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
1829                                  errmsg("permission denied: \"%s\" is a system catalog",
1830                                                 RelationGetRelationName(targetrelation))));
1831
1832         /*
1833          * if the 'recurse' flag is set then we are supposed to rename this
1834          * attribute in all classes that inherit from 'relname' (as well as in
1835          * 'relname').
1836          *
1837          * any permissions or problems with duplicate attributes will cause the
1838          * whole transaction to abort, which is what we want -- all or nothing.
1839          */
1840         if (recurse)
1841         {
1842                 ListCell   *child;
1843                 List       *children;
1844
1845                 /* this routine is actually in the planner */
1846                 children = find_all_inheritors(myrelid);
1847
1848                 /*
1849                  * find_all_inheritors does the recursive search of the inheritance
1850                  * hierarchy, so all we have to do is process all of the relids in the
1851                  * list that it returns.
1852                  */
1853                 foreach(child, children)
1854                 {
1855                         Oid                     childrelid = lfirst_oid(child);
1856
1857                         if (childrelid == myrelid)
1858                                 continue;
1859                         /* note we need not recurse again */
1860                         renameatt(childrelid, oldattname, newattname, false, true);
1861                 }
1862         }
1863         else
1864         {
1865                 /*
1866                  * If we are told not to recurse, there had better not be any child
1867                  * tables; else the rename would put them out of step.
1868                  */
1869                 if (!recursing &&
1870                         find_inheritance_children(myrelid) != NIL)
1871                         ereport(ERROR,
1872                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
1873                                          errmsg("inherited column \"%s\" must be renamed in child tables too",
1874                                                         oldattname)));
1875         }
1876
1877         attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
1878
1879         atttup = SearchSysCacheCopyAttName(myrelid, oldattname);
1880         if (!HeapTupleIsValid(atttup))
1881                 ereport(ERROR,
1882                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
1883                                  errmsg("column \"%s\" does not exist",
1884                                                 oldattname)));
1885         attform = (Form_pg_attribute) GETSTRUCT(atttup);
1886
1887         attnum = attform->attnum;
1888         if (attnum <= 0)
1889                 ereport(ERROR,
1890                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1891                                  errmsg("cannot rename system column \"%s\"",
1892                                                 oldattname)));
1893
1894         /*
1895          * if the attribute is inherited, forbid the renaming, unless we are
1896          * already inside a recursive rename.
1897          */
1898         if (attform->attinhcount > 0 && !recursing)
1899                 ereport(ERROR,
1900                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
1901                                  errmsg("cannot rename inherited column \"%s\"",
1902                                                 oldattname)));
1903
1904         /* should not already exist */
1905         /* this test is deliberately not attisdropped-aware */
1906         if (SearchSysCacheExists(ATTNAME,
1907                                                          ObjectIdGetDatum(myrelid),
1908                                                          PointerGetDatum(newattname),
1909                                                          0, 0))
1910                 ereport(ERROR,
1911                                 (errcode(ERRCODE_DUPLICATE_COLUMN),
1912                                  errmsg("column \"%s\" of relation \"%s\" already exists",
1913                                           newattname, RelationGetRelationName(targetrelation))));
1914
1915         namestrcpy(&(attform->attname), newattname);
1916
1917         simple_heap_update(attrelation, &atttup->t_self, atttup);
1918
1919         /* keep system catalog indexes current */
1920         CatalogUpdateIndexes(attrelation, atttup);
1921
1922         heap_freetuple(atttup);
1923
1924         /*
1925          * Update column names of indexes that refer to the column being renamed.
1926          */
1927         indexoidlist = RelationGetIndexList(targetrelation);
1928
1929         foreach(indexoidscan, indexoidlist)
1930         {
1931                 Oid                     indexoid = lfirst_oid(indexoidscan);
1932                 HeapTuple       indextup;
1933                 Form_pg_index indexform;
1934                 int                     i;
1935
1936                 /*
1937                  * Scan through index columns to see if there's any simple index
1938                  * entries for this attribute.  We ignore expressional entries.
1939                  */
1940                 indextup = SearchSysCache(INDEXRELID,
1941                                                                   ObjectIdGetDatum(indexoid),
1942                                                                   0, 0, 0);
1943                 if (!HeapTupleIsValid(indextup))
1944                         elog(ERROR, "cache lookup failed for index %u", indexoid);
1945                 indexform = (Form_pg_index) GETSTRUCT(indextup);
1946
1947                 for (i = 0; i < indexform->indnatts; i++)
1948                 {
1949                         if (attnum != indexform->indkey.values[i])
1950                                 continue;
1951
1952                         /*
1953                          * Found one, rename it.
1954                          */
1955                         atttup = SearchSysCacheCopy(ATTNUM,
1956                                                                                 ObjectIdGetDatum(indexoid),
1957                                                                                 Int16GetDatum(i + 1),
1958                                                                                 0, 0);
1959                         if (!HeapTupleIsValid(atttup))
1960                                 continue;               /* should we raise an error? */
1961
1962                         /*
1963                          * Update the (copied) attribute tuple.
1964                          */
1965                         namestrcpy(&(((Form_pg_attribute) GETSTRUCT(atttup))->attname),
1966                                            newattname);
1967
1968                         simple_heap_update(attrelation, &atttup->t_self, atttup);
1969
1970                         /* keep system catalog indexes current */
1971                         CatalogUpdateIndexes(attrelation, atttup);
1972
1973                         heap_freetuple(atttup);
1974                 }
1975
1976                 ReleaseSysCache(indextup);
1977         }
1978
1979         list_free(indexoidlist);
1980
1981         heap_close(attrelation, RowExclusiveLock);
1982
1983         relation_close(targetrelation, NoLock);         /* close rel but keep lock */
1984 }
1985
1986
1987 /*
1988  * Execute ALTER TABLE/INDEX/SEQUENCE/VIEW RENAME
1989  *
1990  * Caller has already done permissions checks.
1991  */
1992 void
1993 RenameRelation(Oid myrelid, const char *newrelname, ObjectType reltype)
1994 {
1995         Relation        targetrelation;
1996         Oid                     namespaceId;
1997         char            relkind;
1998
1999         /*
2000          * Grab an exclusive lock on the target table, index, sequence or view,
2001          * which we will NOT release until end of transaction.
2002          */
2003         targetrelation = relation_open(myrelid, AccessExclusiveLock);
2004
2005         namespaceId = RelationGetNamespace(targetrelation);
2006         relkind = targetrelation->rd_rel->relkind;
2007
2008         /*
2009          * For compatibility with prior releases, we don't complain if ALTER TABLE
2010          * or ALTER INDEX is used to rename a sequence or view.
2011          */
2012         if (reltype == OBJECT_SEQUENCE && relkind != RELKIND_SEQUENCE)
2013                 ereport(ERROR,
2014                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
2015                                  errmsg("\"%s\" is not a sequence",
2016                                                 RelationGetRelationName(targetrelation))));
2017
2018         if (reltype == OBJECT_VIEW && relkind != RELKIND_VIEW)
2019                 ereport(ERROR,
2020                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
2021                                  errmsg("\"%s\" is not a view",
2022                                                 RelationGetRelationName(targetrelation))));
2023
2024         /*
2025          * Don't allow ALTER TABLE on composite types.
2026          * We want people to use ALTER TYPE for that.
2027          */
2028         if (relkind == RELKIND_COMPOSITE_TYPE)
2029                 ereport(ERROR,
2030                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
2031                                  errmsg("\"%s\" is a composite type",
2032                                                 RelationGetRelationName(targetrelation)),
2033                                  errhint("Use ALTER TYPE instead.")));
2034
2035         /* Do the work */
2036         RenameRelationInternal(myrelid, newrelname, namespaceId);
2037
2038         /*
2039          * Close rel, but keep exclusive lock!
2040          */
2041         relation_close(targetrelation, NoLock);
2042 }
2043
2044 /*
2045  *              RenameRelationInternal - change the name of a relation
2046  *
2047  *              XXX - When renaming sequences, we don't bother to modify the
2048  *                        sequence name that is stored within the sequence itself
2049  *                        (this would cause problems with MVCC). In the future,
2050  *                        the sequence name should probably be removed from the
2051  *                        sequence, AFAIK there's no need for it to be there.
2052  */
2053 void
2054 RenameRelationInternal(Oid myrelid, const char *newrelname, Oid namespaceId)
2055 {
2056         Relation        targetrelation;
2057         Relation        relrelation;    /* for RELATION relation */
2058         HeapTuple       reltup;
2059         Form_pg_class relform;
2060
2061         /*
2062          * Grab an exclusive lock on the target table, index, sequence or
2063          * view, which we will NOT release until end of transaction.
2064          */
2065         targetrelation = relation_open(myrelid, AccessExclusiveLock);
2066
2067         /*
2068          * Find relation's pg_class tuple, and make sure newrelname isn't in use.
2069          */
2070         relrelation = heap_open(RelationRelationId, RowExclusiveLock);
2071
2072         reltup = SearchSysCacheCopy(RELOID,
2073                                                                 ObjectIdGetDatum(myrelid),
2074                                                                 0, 0, 0);
2075         if (!HeapTupleIsValid(reltup))          /* shouldn't happen */
2076                 elog(ERROR, "cache lookup failed for relation %u", myrelid);
2077         relform = (Form_pg_class) GETSTRUCT(reltup);
2078
2079         if (get_relname_relid(newrelname, namespaceId) != InvalidOid)
2080                 ereport(ERROR,
2081                                 (errcode(ERRCODE_DUPLICATE_TABLE),
2082                                  errmsg("relation \"%s\" already exists",
2083                                                 newrelname)));
2084
2085         /*
2086          * Update pg_class tuple with new relname.      (Scribbling on reltup is OK
2087          * because it's a copy...)
2088          */
2089         namestrcpy(&(relform->relname), newrelname);
2090
2091         simple_heap_update(relrelation, &reltup->t_self, reltup);
2092
2093         /* keep the system catalog indexes current */
2094         CatalogUpdateIndexes(relrelation, reltup);
2095
2096         heap_freetuple(reltup);
2097         heap_close(relrelation, RowExclusiveLock);
2098
2099         /*
2100          * Also rename the associated type, if any.
2101          */
2102         if (OidIsValid(targetrelation->rd_rel->reltype))
2103                 RenameTypeInternal(targetrelation->rd_rel->reltype,
2104                                                    newrelname, namespaceId);
2105
2106         /*
2107          * Also rename the associated constraint, if any.
2108          */
2109         if (targetrelation->rd_rel->relkind == RELKIND_INDEX)
2110         {
2111                 Oid                     constraintId = get_index_constraint(myrelid);
2112
2113                 if (OidIsValid(constraintId))
2114                         RenameConstraintById(constraintId, newrelname);
2115         }
2116
2117         /*
2118          * Close rel, but keep exclusive lock!
2119          */
2120         relation_close(targetrelation, NoLock);
2121 }
2122
2123 /*
2124  * Disallow ALTER TABLE (and similar commands) when the current backend has
2125  * any open reference to the target table besides the one just acquired by
2126  * the calling command; this implies there's an open cursor or active plan.
2127  * We need this check because our AccessExclusiveLock doesn't protect us
2128  * against stomping on our own foot, only other people's feet!
2129  *
2130  * For ALTER TABLE, the only case known to cause serious trouble is ALTER
2131  * COLUMN TYPE, and some changes are obviously pretty benign, so this could
2132  * possibly be relaxed to only error out for certain types of alterations.
2133  * But the use-case for allowing any of these things is not obvious, so we
2134  * won't work hard at it for now.
2135  *
2136  * We also reject these commands if there are any pending AFTER trigger events
2137  * for the rel.  This is certainly necessary for the rewriting variants of
2138  * ALTER TABLE, because they don't preserve tuple TIDs and so the pending
2139  * events would try to fetch the wrong tuples.  It might be overly cautious
2140  * in other cases, but again it seems better to err on the side of paranoia.
2141  *
2142  * REINDEX calls this with "rel" referencing the index to be rebuilt; here
2143  * we are worried about active indexscans on the index.  The trigger-event
2144  * check can be skipped, since we are doing no damage to the parent table.
2145  *
2146  * The statement name (eg, "ALTER TABLE") is passed for use in error messages.
2147  */
2148 void
2149 CheckTableNotInUse(Relation rel, const char *stmt)
2150 {
2151         int                     expected_refcnt;
2152
2153         expected_refcnt = rel->rd_isnailed ? 2 : 1;
2154         if (rel->rd_refcnt != expected_refcnt)
2155                 ereport(ERROR,
2156                                 (errcode(ERRCODE_OBJECT_IN_USE),
2157                                  /* translator: first %s is a SQL command, eg ALTER TABLE */
2158                                  errmsg("cannot %s \"%s\" because "
2159                                                 "it is being used by active queries in this session",
2160                                                 stmt, RelationGetRelationName(rel))));
2161
2162         if (rel->rd_rel->relkind != RELKIND_INDEX &&
2163                 AfterTriggerPendingOnRel(RelationGetRelid(rel)))
2164                 ereport(ERROR,
2165                                 (errcode(ERRCODE_OBJECT_IN_USE),
2166                                  /* translator: first %s is a SQL command, eg ALTER TABLE */
2167                                  errmsg("cannot %s \"%s\" because "
2168                                                 "it has pending trigger events",
2169                                                 stmt, RelationGetRelationName(rel))));
2170 }
2171
2172 /*
2173  * AlterTable
2174  *              Execute ALTER TABLE, which can be a list of subcommands
2175  *
2176  * ALTER TABLE is performed in three phases:
2177  *              1. Examine subcommands and perform pre-transformation checking.
2178  *              2. Update system catalogs.
2179  *              3. Scan table(s) to check new constraints, and optionally recopy
2180  *                 the data into new table(s).
2181  * Phase 3 is not performed unless one or more of the subcommands requires
2182  * it.  The intention of this design is to allow multiple independent
2183  * updates of the table schema to be performed with only one pass over the
2184  * data.
2185  *
2186  * ATPrepCmd performs phase 1.  A "work queue" entry is created for
2187  * each table to be affected (there may be multiple affected tables if the
2188  * commands traverse a table inheritance hierarchy).  Also we do preliminary
2189  * validation of the subcommands, including parse transformation of those
2190  * expressions that need to be evaluated with respect to the old table
2191  * schema.
2192  *
2193  * ATRewriteCatalogs performs phase 2 for each affected table.  (Note that
2194  * phases 2 and 3 normally do no explicit recursion, since phase 1 already
2195  * did it --- although some subcommands have to recurse in phase 2 instead.)
2196  * Certain subcommands need to be performed before others to avoid
2197  * unnecessary conflicts; for example, DROP COLUMN should come before
2198  * ADD COLUMN.  Therefore phase 1 divides the subcommands into multiple
2199  * lists, one for each logical "pass" of phase 2.
2200  *
2201  * ATRewriteTables performs phase 3 for those tables that need it.
2202  *
2203  * Thanks to the magic of MVCC, an error anywhere along the way rolls back
2204  * the whole operation; we don't have to do anything special to clean up.
2205  */
2206 void
2207 AlterTable(AlterTableStmt *stmt)
2208 {
2209         Relation        rel = relation_openrv(stmt->relation, AccessExclusiveLock);
2210
2211         CheckTableNotInUse(rel, "ALTER TABLE");
2212
2213         /* Check relation type against type specified in the ALTER command */
2214         switch (stmt->relkind)
2215         {
2216                 case OBJECT_TABLE:
2217                         /*
2218                          * For mostly-historical reasons, we allow ALTER TABLE to apply
2219                          * to all relation types.
2220                          */
2221                         break;
2222
2223                 case OBJECT_INDEX:
2224                         if (rel->rd_rel->relkind != RELKIND_INDEX)
2225                                 ereport(ERROR,
2226                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
2227                                                  errmsg("\"%s\" is not an index",
2228                                                                 RelationGetRelationName(rel))));
2229                         break;
2230
2231                 case OBJECT_SEQUENCE:
2232                         if (rel->rd_rel->relkind != RELKIND_SEQUENCE)
2233                                 ereport(ERROR,
2234                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
2235                                                  errmsg("\"%s\" is not a sequence",
2236                                                                 RelationGetRelationName(rel))));
2237                         break;
2238
2239                 case OBJECT_VIEW:
2240                         if (rel->rd_rel->relkind != RELKIND_VIEW)
2241                                 ereport(ERROR,
2242                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
2243                                                  errmsg("\"%s\" is not a view",
2244                                                                 RelationGetRelationName(rel))));
2245                         break;
2246
2247                 default:
2248                         elog(ERROR, "unrecognized object type: %d", (int) stmt->relkind);
2249         }
2250
2251         ATController(rel, stmt->cmds, interpretInhOption(stmt->relation->inhOpt));
2252 }
2253
2254 /*
2255  * AlterTableInternal
2256  *
2257  * ALTER TABLE with target specified by OID
2258  *
2259  * We do not reject if the relation is already open, because it's quite
2260  * likely that one or more layers of caller have it open.  That means it
2261  * is unsafe to use this entry point for alterations that could break
2262  * existing query plans.  On the assumption it's not used for such, we
2263  * don't have to reject pending AFTER triggers, either.
2264  */
2265 void
2266 AlterTableInternal(Oid relid, List *cmds, bool recurse)
2267 {
2268         Relation        rel = relation_open(relid, AccessExclusiveLock);
2269
2270         ATController(rel, cmds, recurse);
2271 }
2272
2273 static void
2274 ATController(Relation rel, List *cmds, bool recurse)
2275 {
2276         List       *wqueue = NIL;
2277         ListCell   *lcmd;
2278
2279         /* Phase 1: preliminary examination of commands, create work queue */
2280         foreach(lcmd, cmds)
2281         {
2282                 AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd);
2283
2284                 ATPrepCmd(&wqueue, rel, cmd, recurse, false);
2285         }
2286
2287         /* Close the relation, but keep lock until commit */
2288         relation_close(rel, NoLock);
2289
2290         /* Phase 2: update system catalogs */
2291         ATRewriteCatalogs(&wqueue);
2292
2293         /* Phase 3: scan/rewrite tables as needed */
2294         ATRewriteTables(&wqueue);
2295 }
2296
2297 /*
2298  * ATPrepCmd
2299  *
2300  * Traffic cop for ALTER TABLE Phase 1 operations, including simple
2301  * recursion and permission checks.
2302  *
2303  * Caller must have acquired AccessExclusiveLock on relation already.
2304  * This lock should be held until commit.
2305  */
2306 static void
2307 ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
2308                   bool recurse, bool recursing)
2309 {
2310         AlteredTableInfo *tab;
2311         int                     pass;
2312
2313         /* Find or create work queue entry for this table */
2314         tab = ATGetQueueEntry(wqueue, rel);
2315
2316         /*
2317          * Copy the original subcommand for each table.  This avoids conflicts
2318          * when different child tables need to make different parse
2319          * transformations (for example, the same column may have different column
2320          * numbers in different children).
2321          */
2322         cmd = copyObject(cmd);
2323
2324         /*
2325          * Do permissions checking, recursion to child tables if needed, and any
2326          * additional phase-1 processing needed.
2327          */
2328         switch (cmd->subtype)
2329         {
2330                 case AT_AddColumn:              /* ADD COLUMN */
2331                         ATSimplePermissions(rel, false);
2332                         /* Performs own recursion */
2333                         ATPrepAddColumn(wqueue, rel, recurse, cmd);
2334                         pass = AT_PASS_ADD_COL;
2335                         break;
2336                 case AT_ColumnDefault:  /* ALTER COLUMN DEFAULT */
2337
2338                         /*
2339                          * We allow defaults on views so that INSERT into a view can have
2340                          * default-ish behavior.  This works because the rewriter
2341                          * substitutes default values into INSERTs before it expands
2342                          * rules.
2343                          */
2344                         ATSimplePermissions(rel, true);
2345                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
2346                         /* No command-specific prep needed */
2347                         pass = cmd->def ? AT_PASS_ADD_CONSTR : AT_PASS_DROP;
2348                         break;
2349                 case AT_DropNotNull:    /* ALTER COLUMN DROP NOT NULL */
2350                         ATSimplePermissions(rel, false);
2351                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
2352                         /* No command-specific prep needed */
2353                         pass = AT_PASS_DROP;
2354                         break;
2355                 case AT_SetNotNull:             /* ALTER COLUMN SET NOT NULL */
2356                         ATSimplePermissions(rel, false);
2357                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
2358                         /* No command-specific prep needed */
2359                         pass = AT_PASS_ADD_CONSTR;
2360                         break;
2361                 case AT_SetStatistics:  /* ALTER COLUMN STATISTICS */
2362                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
2363                         /* Performs own permission checks */
2364                         ATPrepSetStatistics(rel, cmd->name, cmd->def);
2365                         pass = AT_PASS_COL_ATTRS;
2366                         break;
2367                 case AT_SetStorage:             /* ALTER COLUMN STORAGE */
2368                         ATSimplePermissions(rel, false);
2369                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
2370                         /* No command-specific prep needed */
2371                         pass = AT_PASS_COL_ATTRS;
2372                         break;
2373                 case AT_DropColumn:             /* DROP COLUMN */
2374                         ATSimplePermissions(rel, false);
2375                         /* Recursion occurs during execution phase */
2376                         /* No command-specific prep needed except saving recurse flag */
2377                         if (recurse)
2378                                 cmd->subtype = AT_DropColumnRecurse;
2379                         pass = AT_PASS_DROP;
2380                         break;
2381                 case AT_AddIndex:               /* ADD INDEX */
2382                         ATSimplePermissions(rel, false);
2383                         /* This command never recurses */
2384                         /* No command-specific prep needed */
2385                         pass = AT_PASS_ADD_INDEX;
2386                         break;
2387                 case AT_AddConstraint:  /* ADD CONSTRAINT */
2388                         ATSimplePermissions(rel, false);
2389                         /* Recursion occurs during execution phase */
2390                         /* No command-specific prep needed except saving recurse flag */
2391                         if (recurse)
2392                                 cmd->subtype = AT_AddConstraintRecurse;
2393                         pass = AT_PASS_ADD_CONSTR;
2394                         break;
2395                 case AT_DropConstraint: /* DROP CONSTRAINT */
2396                         ATSimplePermissions(rel, false);
2397                         /* Recursion occurs during execution phase */
2398                         /* No command-specific prep needed except saving recurse flag */
2399                         if (recurse)
2400                                 cmd->subtype = AT_DropConstraintRecurse;
2401                         pass = AT_PASS_DROP;
2402                         break;
2403                 case AT_AlterColumnType:                /* ALTER COLUMN TYPE */
2404                         ATSimplePermissions(rel, false);
2405                         /* Performs own recursion */
2406                         ATPrepAlterColumnType(wqueue, tab, rel, recurse, recursing, cmd);
2407                         pass = AT_PASS_ALTER_TYPE;
2408                         break;
2409                 case AT_ChangeOwner:    /* ALTER OWNER */
2410                         /* This command never recurses */
2411                         /* No command-specific prep needed */
2412                         pass = AT_PASS_MISC;
2413                         break;
2414                 case AT_ClusterOn:              /* CLUSTER ON */
2415                 case AT_DropCluster:    /* SET WITHOUT CLUSTER */
2416                         ATSimplePermissions(rel, false);
2417                         /* These commands never recurse */
2418                         /* No command-specific prep needed */
2419                         pass = AT_PASS_MISC;
2420                         break;
2421                 case AT_DropOids:               /* SET WITHOUT OIDS */
2422                         ATSimplePermissions(rel, false);
2423                         /* Performs own recursion */
2424                         if (rel->rd_rel->relhasoids)
2425                         {
2426                                 AlterTableCmd *dropCmd = makeNode(AlterTableCmd);
2427
2428                                 dropCmd->subtype = AT_DropColumn;
2429                                 dropCmd->name = pstrdup("oid");
2430                                 dropCmd->behavior = cmd->behavior;
2431                                 ATPrepCmd(wqueue, rel, dropCmd, recurse, false);
2432                         }
2433                         pass = AT_PASS_DROP;
2434                         break;
2435                 case AT_SetTableSpace:  /* SET TABLESPACE */
2436                         ATSimplePermissionsRelationOrIndex(rel);
2437                         /* This command never recurses */
2438                         ATPrepSetTableSpace(tab, rel, cmd->name);
2439                         pass = AT_PASS_MISC;    /* doesn't actually matter */
2440                         break;
2441                 case AT_SetRelOptions:  /* SET (...) */
2442                 case AT_ResetRelOptions:                /* RESET (...) */
2443                         ATSimplePermissionsRelationOrIndex(rel);
2444                         /* This command never recurses */
2445                         /* No command-specific prep needed */
2446                         pass = AT_PASS_MISC;
2447                         break;
2448                 case AT_EnableTrig:             /* ENABLE TRIGGER variants */
2449                 case AT_EnableAlwaysTrig:
2450                 case AT_EnableReplicaTrig:
2451                 case AT_EnableTrigAll:
2452                 case AT_EnableTrigUser:
2453                 case AT_DisableTrig:    /* DISABLE TRIGGER variants */
2454                 case AT_DisableTrigAll:
2455                 case AT_DisableTrigUser:
2456                 case AT_EnableRule:             /* ENABLE/DISABLE RULE variants */
2457                 case AT_EnableAlwaysRule:
2458                 case AT_EnableReplicaRule:
2459                 case AT_DisableRule:
2460                 case AT_AddInherit:             /* INHERIT / NO INHERIT */
2461                 case AT_DropInherit:
2462                         ATSimplePermissions(rel, false);
2463                         /* These commands never recurse */
2464                         /* No command-specific prep needed */
2465                         pass = AT_PASS_MISC;
2466                         break;
2467                 default:                                /* oops */
2468                         elog(ERROR, "unrecognized alter table type: %d",
2469                                  (int) cmd->subtype);
2470                         pass = 0;                       /* keep compiler quiet */
2471                         break;
2472         }
2473
2474         /* Add the subcommand to the appropriate list for phase 2 */
2475         tab->subcmds[pass] = lappend(tab->subcmds[pass], cmd);
2476 }
2477
2478 /*
2479  * ATRewriteCatalogs
2480  *
2481  * Traffic cop for ALTER TABLE Phase 2 operations.      Subcommands are
2482  * dispatched in a "safe" execution order (designed to avoid unnecessary
2483  * conflicts).
2484  */
2485 static void
2486 ATRewriteCatalogs(List **wqueue)
2487 {
2488         int                     pass;
2489         ListCell   *ltab;
2490
2491         /*
2492          * We process all the tables "in parallel", one pass at a time.  This is
2493          * needed because we may have to propagate work from one table to another
2494          * (specifically, ALTER TYPE on a foreign key's PK has to dispatch the
2495          * re-adding of the foreign key constraint to the other table).  Work can
2496          * only be propagated into later passes, however.
2497          */
2498         for (pass = 0; pass < AT_NUM_PASSES; pass++)
2499         {
2500                 /* Go through each table that needs to be processed */
2501                 foreach(ltab, *wqueue)
2502                 {
2503                         AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
2504                         List       *subcmds = tab->subcmds[pass];
2505                         Relation        rel;
2506                         ListCell   *lcmd;
2507
2508                         if (subcmds == NIL)
2509                                 continue;
2510
2511                         /*
2512                          * Exclusive lock was obtained by phase 1, needn't get it again
2513                          */
2514                         rel = relation_open(tab->relid, NoLock);
2515
2516                         foreach(lcmd, subcmds)
2517                                 ATExecCmd(wqueue, tab, rel, (AlterTableCmd *) lfirst(lcmd));
2518
2519                         /*
2520                          * After the ALTER TYPE pass, do cleanup work (this is not done in
2521                          * ATExecAlterColumnType since it should be done only once if
2522                          * multiple columns of a table are altered).
2523                          */
2524                         if (pass == AT_PASS_ALTER_TYPE)
2525                                 ATPostAlterTypeCleanup(wqueue, tab);
2526
2527                         relation_close(rel, NoLock);
2528                 }
2529         }
2530
2531         /*
2532          * Check to see if a toast table must be added, if we executed any
2533          * subcommands that might have added a column or changed column storage.
2534          */
2535         foreach(ltab, *wqueue)
2536         {
2537                 AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
2538
2539                 if (tab->relkind == RELKIND_RELATION &&
2540                         (tab->subcmds[AT_PASS_ADD_COL] ||
2541                          tab->subcmds[AT_PASS_ALTER_TYPE] ||
2542                          tab->subcmds[AT_PASS_COL_ATTRS]))
2543                         AlterTableCreateToastTable(tab->relid);
2544         }
2545 }
2546
2547 /*
2548  * ATExecCmd: dispatch a subcommand to appropriate execution routine
2549  */
2550 static void
2551 ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
2552                   AlterTableCmd *cmd)
2553 {
2554         switch (cmd->subtype)
2555         {
2556                 case AT_AddColumn:              /* ADD COLUMN */
2557                         ATExecAddColumn(tab, rel, (ColumnDef *) cmd->def);
2558                         break;
2559                 case AT_ColumnDefault:  /* ALTER COLUMN DEFAULT */
2560                         ATExecColumnDefault(rel, cmd->name, cmd->def);
2561                         break;
2562                 case AT_DropNotNull:    /* ALTER COLUMN DROP NOT NULL */
2563                         ATExecDropNotNull(rel, cmd->name);
2564                         break;
2565                 case AT_SetNotNull:             /* ALTER COLUMN SET NOT NULL */
2566                         ATExecSetNotNull(tab, rel, cmd->name);
2567                         break;
2568                 case AT_SetStatistics:  /* ALTER COLUMN STATISTICS */
2569                         ATExecSetStatistics(rel, cmd->name, cmd->def);
2570                         break;
2571                 case AT_SetStorage:             /* ALTER COLUMN STORAGE */
2572                         ATExecSetStorage(rel, cmd->name, cmd->def);
2573                         break;
2574                 case AT_DropColumn:             /* DROP COLUMN */
2575                         ATExecDropColumn(rel, cmd->name, cmd->behavior, false, false);
2576                         break;
2577                 case AT_DropColumnRecurse:              /* DROP COLUMN with recursion */
2578                         ATExecDropColumn(rel, cmd->name, cmd->behavior, true, false);
2579                         break;
2580                 case AT_AddIndex:               /* ADD INDEX */
2581                         ATExecAddIndex(tab, rel, (IndexStmt *) cmd->def, false);
2582                         break;
2583                 case AT_ReAddIndex:             /* ADD INDEX */
2584                         ATExecAddIndex(tab, rel, (IndexStmt *) cmd->def, true);
2585                         break;
2586                 case AT_AddConstraint:  /* ADD CONSTRAINT */
2587                         ATExecAddConstraint(wqueue, tab, rel, cmd->def, false);
2588                         break;
2589                 case AT_AddConstraintRecurse:   /* ADD CONSTRAINT with recursion */
2590                         ATExecAddConstraint(wqueue, tab, rel, cmd->def, true);
2591                         break;
2592                 case AT_DropConstraint: /* DROP CONSTRAINT */
2593                         ATExecDropConstraint(rel, cmd->name, cmd->behavior, false, false);
2594                         break;
2595                 case AT_DropConstraintRecurse:  /* DROP CONSTRAINT with recursion */
2596                         ATExecDropConstraint(rel, cmd->name, cmd->behavior, true, false);
2597                         break;
2598                 case AT_AlterColumnType:                /* ALTER COLUMN TYPE */
2599                         ATExecAlterColumnType(tab, rel, cmd->name, (TypeName *) cmd->def);
2600                         break;
2601                 case AT_ChangeOwner:    /* ALTER OWNER */
2602                         ATExecChangeOwner(RelationGetRelid(rel),
2603                                                           get_roleid_checked(cmd->name),
2604                                                           false);
2605                         break;
2606                 case AT_ClusterOn:              /* CLUSTER ON */
2607                         ATExecClusterOn(rel, cmd->name);
2608                         break;
2609                 case AT_DropCluster:    /* SET WITHOUT CLUSTER */
2610                         ATExecDropCluster(rel);
2611                         break;
2612                 case AT_DropOids:               /* SET WITHOUT OIDS */
2613
2614                         /*
2615                          * Nothing to do here; we'll have generated a DropColumn
2616                          * subcommand to do the real work
2617                          */
2618                         break;
2619                 case AT_SetTableSpace:  /* SET TABLESPACE */
2620
2621                         /*
2622                          * Nothing to do here; Phase 3 does the work
2623                          */
2624                         break;
2625                 case AT_SetRelOptions:  /* SET (...) */
2626                         ATExecSetRelOptions(rel, (List *) cmd->def, false);
2627                         break;
2628                 case AT_ResetRelOptions:                /* RESET (...) */
2629                         ATExecSetRelOptions(rel, (List *) cmd->def, true);
2630                         break;
2631
2632                 case AT_EnableTrig:             /* ENABLE TRIGGER name */
2633                         ATExecEnableDisableTrigger(rel, cmd->name,
2634                                                                            TRIGGER_FIRES_ON_ORIGIN, false);
2635                         break;
2636                 case AT_EnableAlwaysTrig:               /* ENABLE ALWAYS TRIGGER name */
2637                         ATExecEnableDisableTrigger(rel, cmd->name,
2638                                                                            TRIGGER_FIRES_ALWAYS, false);
2639                         break;
2640                 case AT_EnableReplicaTrig:              /* ENABLE REPLICA TRIGGER name */
2641                         ATExecEnableDisableTrigger(rel, cmd->name,
2642                                                                            TRIGGER_FIRES_ON_REPLICA, false);
2643                         break;
2644                 case AT_DisableTrig:    /* DISABLE TRIGGER name */
2645                         ATExecEnableDisableTrigger(rel, cmd->name,
2646                                                                            TRIGGER_DISABLED, false);
2647                         break;
2648                 case AT_EnableTrigAll:  /* ENABLE TRIGGER ALL */
2649                         ATExecEnableDisableTrigger(rel, NULL,
2650                                                                            TRIGGER_FIRES_ON_ORIGIN, false);
2651                         break;
2652                 case AT_DisableTrigAll: /* DISABLE TRIGGER ALL */
2653                         ATExecEnableDisableTrigger(rel, NULL,
2654                                                                            TRIGGER_DISABLED, false);
2655                         break;
2656                 case AT_EnableTrigUser: /* ENABLE TRIGGER USER */
2657                         ATExecEnableDisableTrigger(rel, NULL,
2658                                                                            TRIGGER_FIRES_ON_ORIGIN, true);
2659                         break;
2660                 case AT_DisableTrigUser:                /* DISABLE TRIGGER USER */
2661                         ATExecEnableDisableTrigger(rel, NULL,
2662                                                                            TRIGGER_DISABLED, true);
2663                         break;
2664
2665                 case AT_EnableRule:             /* ENABLE RULE name */
2666                         ATExecEnableDisableRule(rel, cmd->name,
2667                                                                         RULE_FIRES_ON_ORIGIN);
2668                         break;
2669                 case AT_EnableAlwaysRule:               /* ENABLE ALWAYS RULE name */
2670                         ATExecEnableDisableRule(rel, cmd->name,
2671                                                                         RULE_FIRES_ALWAYS);
2672                         break;
2673                 case AT_EnableReplicaRule:              /* ENABLE REPLICA RULE name */
2674                         ATExecEnableDisableRule(rel, cmd->name,
2675                                                                         RULE_FIRES_ON_REPLICA);
2676                         break;
2677                 case AT_DisableRule:    /* DISABLE RULE name */
2678                         ATExecEnableDisableRule(rel, cmd->name,
2679                                                                         RULE_DISABLED);
2680                         break;
2681
2682                 case AT_AddInherit:
2683                         ATExecAddInherit(rel, (RangeVar *) cmd->def);
2684                         break;
2685                 case AT_DropInherit:
2686                         ATExecDropInherit(rel, (RangeVar *) cmd->def);
2687                         break;
2688                 default:                                /* oops */
2689                         elog(ERROR, "unrecognized alter table type: %d",
2690                                  (int) cmd->subtype);
2691                         break;
2692         }
2693
2694         /*
2695          * Bump the command counter to ensure the next subcommand in the sequence
2696          * can see the changes so far
2697          */
2698         CommandCounterIncrement();
2699 }
2700
2701 /*
2702  * ATRewriteTables: ALTER TABLE phase 3
2703  */
2704 static void
2705 ATRewriteTables(List **wqueue)
2706 {
2707         ListCell   *ltab;
2708
2709         /* Go through each table that needs to be checked or rewritten */
2710         foreach(ltab, *wqueue)
2711         {
2712                 AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
2713
2714                 /*
2715                  * We only need to rewrite the table if at least one column needs to
2716                  * be recomputed.
2717                  */
2718                 if (tab->newvals != NIL)
2719                 {
2720                         /* Build a temporary relation and copy data */
2721                         Oid                     OIDNewHeap;
2722                         char            NewHeapName[NAMEDATALEN];
2723                         Oid                     NewTableSpace;
2724                         Relation        OldHeap;
2725                         ObjectAddress object;
2726
2727                         OldHeap = heap_open(tab->relid, NoLock);
2728
2729                         /*
2730                          * We can never allow rewriting of shared or nailed-in-cache
2731                          * relations, because we can't support changing their relfilenode
2732                          * values.
2733                          */
2734                         if (OldHeap->rd_rel->relisshared || OldHeap->rd_isnailed)
2735                                 ereport(ERROR,
2736                                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2737                                                  errmsg("cannot rewrite system relation \"%s\"",
2738                                                                 RelationGetRelationName(OldHeap))));
2739
2740                         /*
2741                          * Don't allow rewrite on temp tables of other backends ... their
2742                          * local buffer manager is not going to cope.
2743                          */
2744                         if (isOtherTempNamespace(RelationGetNamespace(OldHeap)))
2745                                 ereport(ERROR,
2746                                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2747                                 errmsg("cannot rewrite temporary tables of other sessions")));
2748
2749                         /*
2750                          * Select destination tablespace (same as original unless user
2751                          * requested a change)
2752                          */
2753                         if (tab->newTableSpace)
2754                                 NewTableSpace = tab->newTableSpace;
2755                         else
2756                                 NewTableSpace = OldHeap->rd_rel->reltablespace;
2757
2758                         heap_close(OldHeap, NoLock);
2759
2760                         /*
2761                          * Create the new heap, using a temporary name in the same
2762                          * namespace as the existing table.  NOTE: there is some risk of
2763                          * collision with user relnames.  Working around this seems more
2764                          * trouble than it's worth; in particular, we can't create the new
2765                          * heap in a different namespace from the old, or we will have
2766                          * problems with the TEMP status of temp tables.
2767                          */
2768                         snprintf(NewHeapName, sizeof(NewHeapName),
2769                                          "pg_temp_%u", tab->relid);
2770
2771                         OIDNewHeap = make_new_heap(tab->relid, NewHeapName, NewTableSpace);
2772
2773                         /*
2774                          * Copy the heap data into the new table with the desired
2775                          * modifications, and test the current data within the table
2776                          * against new constraints generated by ALTER TABLE commands.
2777                          */
2778                         ATRewriteTable(tab, OIDNewHeap);
2779
2780                         /*
2781                          * Swap the physical files of the old and new heaps.  Since we are
2782                          * generating a new heap, we can use RecentXmin for the table's
2783                          * new relfrozenxid because we rewrote all the tuples on
2784                          * ATRewriteTable, so no older Xid remains on the table.
2785                          */
2786                         swap_relation_files(tab->relid, OIDNewHeap, RecentXmin);
2787
2788                         CommandCounterIncrement();
2789
2790                         /* Destroy new heap with old filenode */
2791                         object.classId = RelationRelationId;
2792                         object.objectId = OIDNewHeap;
2793                         object.objectSubId = 0;
2794
2795                         /*
2796                          * The new relation is local to our transaction and we know
2797                          * nothing depends on it, so DROP_RESTRICT should be OK.
2798                          */
2799                         performDeletion(&object, DROP_RESTRICT);
2800                         /* performDeletion does CommandCounterIncrement at end */
2801
2802                         /*
2803                          * Rebuild each index on the relation (but not the toast table,
2804                          * which is all-new anyway).  We do not need
2805                          * CommandCounterIncrement() because reindex_relation does it.
2806                          */
2807                         reindex_relation(tab->relid, false);
2808                 }
2809                 else
2810                 {
2811                         /*
2812                          * Test the current data within the table against new constraints
2813                          * generated by ALTER TABLE commands, but don't rebuild data.
2814                          */
2815                         if (tab->constraints != NIL || tab->new_notnull)
2816                                 ATRewriteTable(tab, InvalidOid);
2817
2818                         /*
2819                          * If we had SET TABLESPACE but no reason to reconstruct tuples,
2820                          * just do a block-by-block copy.
2821                          */
2822                         if (tab->newTableSpace)
2823                                 ATExecSetTableSpace(tab->relid, tab->newTableSpace);
2824                 }
2825         }
2826
2827         /*
2828          * Foreign key constraints are checked in a final pass, since (a) it's
2829          * generally best to examine each one separately, and (b) it's at least
2830          * theoretically possible that we have changed both relations of the
2831          * foreign key, and we'd better have finished both rewrites before we try
2832          * to read the tables.
2833          */
2834         foreach(ltab, *wqueue)
2835         {
2836                 AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
2837                 Relation        rel = NULL;
2838                 ListCell   *lcon;
2839
2840                 foreach(lcon, tab->constraints)
2841                 {
2842                         NewConstraint *con = lfirst(lcon);
2843
2844                         if (con->contype == CONSTR_FOREIGN)
2845                         {
2846                                 FkConstraint *fkconstraint = (FkConstraint *) con->qual;
2847                                 Relation        refrel;
2848
2849                                 if (rel == NULL)
2850                                 {
2851                                         /* Long since locked, no need for another */
2852                                         rel = heap_open(tab->relid, NoLock);
2853                                 }
2854
2855                                 refrel = heap_open(con->refrelid, RowShareLock);
2856
2857                                 validateForeignKeyConstraint(fkconstraint, rel, refrel,
2858                                                                                          con->conid);
2859
2860                                 heap_close(refrel, NoLock);
2861                         }
2862                 }
2863
2864                 if (rel)
2865                         heap_close(rel, NoLock);
2866         }
2867 }
2868
2869 /*
2870  * ATRewriteTable: scan or rewrite one table
2871  *
2872  * OIDNewHeap is InvalidOid if we don't need to rewrite
2873  */
2874 static void
2875 ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
2876 {
2877         Relation        oldrel;
2878         Relation        newrel;
2879         TupleDesc       oldTupDesc;
2880         TupleDesc       newTupDesc;
2881         bool            needscan = false;
2882         List       *notnull_attrs;
2883         int                     i;
2884         ListCell   *l;
2885         EState     *estate;
2886
2887         /*
2888          * Open the relation(s).  We have surely already locked the existing
2889          * table.
2890          */
2891         oldrel = heap_open(tab->relid, NoLock);
2892         oldTupDesc = tab->oldDesc;
2893         newTupDesc = RelationGetDescr(oldrel);          /* includes all mods */
2894
2895         if (OidIsValid(OIDNewHeap))
2896                 newrel = heap_open(OIDNewHeap, AccessExclusiveLock);
2897         else
2898                 newrel = NULL;
2899
2900         /*
2901          * If we need to rewrite the table, the operation has to be propagated to
2902          * tables that use this table's rowtype as a column type.
2903          *
2904          * (Eventually this will probably become true for scans as well, but at
2905          * the moment a composite type does not enforce any constraints, so it's
2906          * not necessary/appropriate to enforce them just during ALTER.)
2907          */
2908         if (newrel)
2909                 find_composite_type_dependencies(oldrel->rd_rel->reltype,
2910                                                                                  RelationGetRelationName(oldrel),
2911                                                                                  NULL);
2912
2913         /*
2914          * Generate the constraint and default execution states
2915          */
2916
2917         estate = CreateExecutorState();
2918
2919         /* Build the needed expression execution states */
2920         foreach(l, tab->constraints)
2921         {
2922                 NewConstraint *con = lfirst(l);
2923
2924                 switch (con->contype)
2925                 {
2926                         case CONSTR_CHECK:
2927                                 needscan = true;
2928                                 con->qualstate = (List *)
2929                                         ExecPrepareExpr((Expr *) con->qual, estate);
2930                                 break;
2931                         case CONSTR_FOREIGN:
2932                                 /* Nothing to do here */
2933                                 break;
2934                         default:
2935                                 elog(ERROR, "unrecognized constraint type: %d",
2936                                          (int) con->contype);
2937                 }
2938         }
2939
2940         foreach(l, tab->newvals)
2941         {
2942                 NewColumnValue *ex = lfirst(l);
2943
2944                 needscan = true;
2945
2946                 ex->exprstate = ExecPrepareExpr((Expr *) ex->expr, estate);
2947         }
2948
2949         notnull_attrs = NIL;
2950         if (newrel || tab->new_notnull)
2951         {
2952                 /*
2953                  * If we are rebuilding the tuples OR if we added any new NOT NULL
2954                  * constraints, check all not-null constraints.  This is a bit of
2955                  * overkill but it minimizes risk of bugs, and heap_attisnull is a
2956                  * pretty cheap test anyway.
2957                  */
2958                 for (i = 0; i < newTupDesc->natts; i++)
2959                 {
2960                         if (newTupDesc->attrs[i]->attnotnull &&
2961                                 !newTupDesc->attrs[i]->attisdropped)
2962                                 notnull_attrs = lappend_int(notnull_attrs, i);
2963                 }
2964                 if (notnull_attrs)
2965                         needscan = true;
2966         }
2967
2968         if (needscan)
2969         {
2970                 ExprContext *econtext;
2971                 Datum      *values;
2972                 bool       *isnull;
2973                 TupleTableSlot *oldslot;
2974                 TupleTableSlot *newslot;
2975                 HeapScanDesc scan;
2976                 HeapTuple       tuple;
2977                 MemoryContext oldCxt;
2978                 List       *dropped_attrs = NIL;
2979                 ListCell   *lc;
2980
2981                 econtext = GetPerTupleExprContext(estate);
2982
2983                 /*
2984                  * Make tuple slots for old and new tuples.  Note that even when the
2985                  * tuples are the same, the tupDescs might not be (consider ADD COLUMN
2986                  * without a default).
2987                  */
2988                 oldslot = MakeSingleTupleTableSlot(oldTupDesc);
2989                 newslot = MakeSingleTupleTableSlot(newTupDesc);
2990
2991                 /* Preallocate values/isnull arrays */
2992                 i = Max(newTupDesc->natts, oldTupDesc->natts);
2993                 values = (Datum *) palloc(i * sizeof(Datum));
2994                 isnull = (bool *) palloc(i * sizeof(bool));
2995                 memset(values, 0, i * sizeof(Datum));
2996                 memset(isnull, true, i * sizeof(bool));
2997
2998                 /*
2999                  * Any attributes that are dropped according to the new tuple
3000                  * descriptor can be set to NULL. We precompute the list of dropped
3001                  * attributes to avoid needing to do so in the per-tuple loop.
3002                  */
3003                 for (i = 0; i < newTupDesc->natts; i++)
3004                 {
3005                         if (newTupDesc->attrs[i]->attisdropped)
3006                                 dropped_attrs = lappend_int(dropped_attrs, i);
3007                 }
3008
3009                 /*
3010                  * Scan through the rows, generating a new row if needed and then
3011                  * checking all the constraints.
3012                  */
3013                 scan = heap_beginscan(oldrel, SnapshotNow, 0, NULL);
3014
3015                 /*
3016                  * Switch to per-tuple memory context and reset it for each tuple
3017                  * produced, so we don't leak memory.
3018                  */
3019                 oldCxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(estate));
3020
3021                 while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
3022                 {
3023                         if (newrel)
3024                         {
3025                                 Oid                     tupOid = InvalidOid;
3026
3027                                 /* Extract data from old tuple */
3028                                 heap_deform_tuple(tuple, oldTupDesc, values, isnull);
3029                                 if (oldTupDesc->tdhasoid)
3030                                         tupOid = HeapTupleGetOid(tuple);
3031
3032                                 /* Set dropped attributes to null in new tuple */
3033                                 foreach(lc, dropped_attrs)
3034                                         isnull[lfirst_int(lc)] = true;
3035
3036                                 /*
3037                                  * Process supplied expressions to replace selected columns.
3038                                  * Expression inputs come from the old tuple.
3039                                  */
3040                                 ExecStoreTuple(tuple, oldslot, InvalidBuffer, false);
3041                                 econtext->ecxt_scantuple = oldslot;
3042
3043                                 foreach(l, tab->newvals)
3044                                 {
3045                                         NewColumnValue *ex = lfirst(l);
3046
3047                                         values[ex->attnum - 1] = ExecEvalExpr(ex->exprstate,
3048                                                                                                                   econtext,
3049                                                                                                          &isnull[ex->attnum - 1],
3050                                                                                                                   NULL);
3051                                 }
3052
3053                                 /*
3054                                  * Form the new tuple. Note that we don't explicitly pfree it,
3055                                  * since the per-tuple memory context will be reset shortly.
3056                                  */
3057                                 tuple = heap_form_tuple(newTupDesc, values, isnull);
3058
3059                                 /* Preserve OID, if any */
3060                                 if (newTupDesc->tdhasoid)
3061                                         HeapTupleSetOid(tuple, tupOid);
3062                         }
3063
3064                         /* Now check any constraints on the possibly-changed tuple */
3065                         ExecStoreTuple(tuple, newslot, InvalidBuffer, false);
3066                         econtext->ecxt_scantuple = newslot;
3067
3068                         foreach(l, notnull_attrs)
3069                         {
3070                                 int                     attn = lfirst_int(l);
3071
3072                                 if (heap_attisnull(tuple, attn + 1))
3073                                         ereport(ERROR,
3074                                                         (errcode(ERRCODE_NOT_NULL_VIOLATION),
3075                                                          errmsg("column \"%s\" contains null values",
3076                                                                 NameStr(newTupDesc->attrs[attn]->attname))));
3077                         }
3078
3079                         foreach(l, tab->constraints)
3080                         {
3081                                 NewConstraint *con = lfirst(l);
3082
3083                                 switch (con->contype)
3084                                 {
3085                                         case CONSTR_CHECK:
3086                                                 if (!ExecQual(con->qualstate, econtext, true))
3087                                                         ereport(ERROR,
3088                                                                         (errcode(ERRCODE_CHECK_VIOLATION),
3089                                                                          errmsg("check constraint \"%s\" is violated by some row",
3090                                                                                         con->name)));
3091                                                 break;
3092                                         case CONSTR_FOREIGN:
3093                                                 /* Nothing to do here */
3094                                                 break;
3095                                         default:
3096                                                 elog(ERROR, "unrecognized constraint type: %d",
3097                                                          (int) con->contype);
3098                                 }
3099                         }
3100
3101                         /* Write the tuple out to the new relation */
3102                         if (newrel)
3103                                 simple_heap_insert(newrel, tuple);
3104
3105                         ResetExprContext(econtext);
3106
3107                         CHECK_FOR_INTERRUPTS();
3108                 }
3109
3110                 MemoryContextSwitchTo(oldCxt);
3111                 heap_endscan(scan);
3112
3113                 ExecDropSingleTupleTableSlot(oldslot);
3114                 ExecDropSingleTupleTableSlot(newslot);
3115         }
3116
3117         FreeExecutorState(estate);
3118
3119         heap_close(oldrel, NoLock);
3120         if (newrel)
3121                 heap_close(newrel, NoLock);
3122 }
3123
3124 /*
3125  * ATGetQueueEntry: find or create an entry in the ALTER TABLE work queue
3126  */
3127 static AlteredTableInfo *
3128 ATGetQueueEntry(List **wqueue, Relation rel)
3129 {
3130         Oid                     relid = RelationGetRelid(rel);
3131         AlteredTableInfo *tab;
3132         ListCell   *ltab;
3133
3134         foreach(ltab, *wqueue)
3135         {
3136                 tab = (AlteredTableInfo *) lfirst(ltab);
3137                 if (tab->relid == relid)
3138                         return tab;
3139         }
3140
3141         /*
3142          * Not there, so add it.  Note that we make a copy of the relation's
3143          * existing descriptor before anything interesting can happen to it.
3144          */
3145         tab = (AlteredTableInfo *) palloc0(sizeof(AlteredTableInfo));
3146         tab->relid = relid;
3147         tab->relkind = rel->rd_rel->relkind;
3148         tab->oldDesc = CreateTupleDescCopy(RelationGetDescr(rel));
3149
3150         *wqueue = lappend(*wqueue, tab);
3151
3152         return tab;
3153 }
3154
3155 /*
3156  * ATSimplePermissions
3157  *
3158  * - Ensure that it is a relation (or possibly a view)
3159  * - Ensure this user is the owner
3160  * - Ensure that it is not a system table
3161  */
3162 static void
3163 ATSimplePermissions(Relation rel, bool allowView)
3164 {
3165         if (rel->rd_rel->relkind != RELKIND_RELATION)
3166         {
3167                 if (allowView)
3168                 {
3169                         if (rel->rd_rel->relkind != RELKIND_VIEW)
3170                                 ereport(ERROR,
3171                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
3172                                                  errmsg("\"%s\" is not a table or view",
3173                                                                 RelationGetRelationName(rel))));
3174                 }
3175                 else
3176                         ereport(ERROR,
3177                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
3178                                          errmsg("\"%s\" is not a table",
3179                                                         RelationGetRelationName(rel))));
3180         }
3181
3182         /* Permissions checks */
3183         if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
3184                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
3185                                            RelationGetRelationName(rel));
3186
3187         if (!allowSystemTableMods && IsSystemRelation(rel))
3188                 ereport(ERROR,
3189                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
3190                                  errmsg("permission denied: \"%s\" is a system catalog",
3191                                                 RelationGetRelationName(rel))));
3192 }
3193
3194 /*
3195  * ATSimplePermissionsRelationOrIndex
3196  *
3197  * - Ensure that it is a relation or an index
3198  * - Ensure this user is the owner
3199  * - Ensure that it is not a system table
3200  */
3201 static void
3202 ATSimplePermissionsRelationOrIndex(Relation rel)
3203 {
3204         if (rel->rd_rel->relkind != RELKIND_RELATION &&
3205                 rel->rd_rel->relkind != RELKIND_INDEX)
3206                 ereport(ERROR,
3207                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
3208                                  errmsg("\"%s\" is not a table or index",
3209                                                 RelationGetRelationName(rel))));
3210
3211         /* Permissions checks */
3212         if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
3213                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
3214                                            RelationGetRelationName(rel));
3215
3216         if (!allowSystemTableMods && IsSystemRelation(rel))
3217                 ereport(ERROR,
3218                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
3219                                  errmsg("permission denied: \"%s\" is a system catalog",
3220                                                 RelationGetRelationName(rel))));
3221 }
3222
3223 /*
3224  * ATSimpleRecursion
3225  *
3226  * Simple table recursion sufficient for most ALTER TABLE operations.
3227  * All direct and indirect children are processed in an unspecified order.
3228  * Note that if a child inherits from the original table via multiple
3229  * inheritance paths, it will be visited just once.
3230  */
3231 static void
3232 ATSimpleRecursion(List **wqueue, Relation rel,
3233                                   AlterTableCmd *cmd, bool recurse)
3234 {
3235         /*
3236          * Propagate to children if desired.  Non-table relations never have
3237          * children, so no need to search in that case.
3238          */
3239         if (recurse && rel->rd_rel->relkind == RELKIND_RELATION)
3240         {
3241                 Oid                     relid = RelationGetRelid(rel);
3242                 ListCell   *child;
3243                 List       *children;
3244
3245                 /* this routine is actually in the planner */
3246                 children = find_all_inheritors(relid);
3247
3248                 /*
3249                  * find_all_inheritors does the recursive search of the inheritance
3250                  * hierarchy, so all we have to do is process all of the relids in the
3251                  * list that it returns.
3252                  */
3253                 foreach(child, children)
3254                 {
3255                         Oid                     childrelid = lfirst_oid(child);
3256                         Relation        childrel;
3257
3258                         if (childrelid == relid)
3259                                 continue;
3260                         childrel = relation_open(childrelid, AccessExclusiveLock);
3261                         CheckTableNotInUse(childrel, "ALTER TABLE");
3262                         ATPrepCmd(wqueue, childrel, cmd, false, true);
3263                         relation_close(childrel, NoLock);
3264                 }
3265         }
3266 }
3267
3268 /*
3269  * ATOneLevelRecursion
3270  *
3271  * Here, we visit only direct inheritance children.  It is expected that
3272  * the command's prep routine will recurse again to find indirect children.
3273  * When using this technique, a multiply-inheriting child will be visited
3274  * multiple times.
3275  */
3276 static void
3277 ATOneLevelRecursion(List **wqueue, Relation rel,
3278                                         AlterTableCmd *cmd)
3279 {
3280         Oid                     relid = RelationGetRelid(rel);
3281         ListCell   *child;
3282         List       *children;
3283
3284         /* this routine is actually in the planner */
3285         children = find_inheritance_children(relid);
3286
3287         foreach(child, children)
3288         {
3289                 Oid                     childrelid = lfirst_oid(child);
3290                 Relation        childrel;
3291
3292                 childrel = relation_open(childrelid, AccessExclusiveLock);
3293                 CheckTableNotInUse(childrel, "ALTER TABLE");
3294                 ATPrepCmd(wqueue, childrel, cmd, true, true);
3295                 relation_close(childrel, NoLock);
3296         }
3297 }
3298
3299
3300 /*
3301  * find_composite_type_dependencies
3302  *
3303  * Check to see if a composite type is being used as a column in some
3304  * other table (possibly nested several levels deep in composite types!).
3305  * Eventually, we'd like to propagate the check or rewrite operation
3306  * into other such tables, but for now, just error out if we find any.
3307  *
3308  * Caller should provide either a table name or a type name (not both) to
3309  * report in the error message, if any.
3310  *
3311  * We assume that functions and views depending on the type are not reasons
3312  * to reject the ALTER.  (How safe is this really?)
3313  */
3314 void
3315 find_composite_type_dependencies(Oid typeOid,
3316                                                                  const char *origTblName,
3317                                                                  const char *origTypeName)
3318 {
3319         Relation        depRel;
3320         ScanKeyData key[2];
3321         SysScanDesc depScan;
3322         HeapTuple       depTup;
3323         Oid                     arrayOid;
3324
3325         /*
3326          * We scan pg_depend to find those things that depend on the rowtype. (We
3327          * assume we can ignore refobjsubid for a rowtype.)
3328          */
3329         depRel = heap_open(DependRelationId, AccessShareLock);
3330
3331         ScanKeyInit(&key[0],
3332                                 Anum_pg_depend_refclassid,
3333                                 BTEqualStrategyNumber, F_OIDEQ,
3334                                 ObjectIdGetDatum(TypeRelationId));
3335         ScanKeyInit(&key[1],
3336                                 Anum_pg_depend_refobjid,
3337                                 BTEqualStrategyNumber, F_OIDEQ,
3338                                 ObjectIdGetDatum(typeOid));
3339
3340         depScan = systable_beginscan(depRel, DependReferenceIndexId, true,
3341                                                                  SnapshotNow, 2, key);
3342
3343         while (HeapTupleIsValid(depTup = systable_getnext(depScan)))
3344         {
3345                 Form_pg_depend pg_depend = (Form_pg_depend) GETSTRUCT(depTup);
3346                 Relation        rel;
3347                 Form_pg_attribute att;
3348
3349                 /* Ignore dependees that aren't user columns of relations */
3350                 /* (we assume system columns are never of rowtypes) */
3351                 if (pg_depend->classid != RelationRelationId ||
3352                         pg_depend->objsubid <= 0)
3353                         continue;
3354
3355                 rel = relation_open(pg_depend->objid, AccessShareLock);
3356                 att = rel->rd_att->attrs[pg_depend->objsubid - 1];
3357
3358                 if (rel->rd_rel->relkind == RELKIND_RELATION)
3359                 {
3360                         if (origTblName)
3361                                 ereport(ERROR,
3362                                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3363                                                  errmsg("cannot alter table \"%s\" because column \"%s\".\"%s\" uses its rowtype",
3364                                                                 origTblName,
3365                                                                 RelationGetRelationName(rel),
3366                                                                 NameStr(att->attname))));
3367                         else
3368                                 ereport(ERROR,
3369                                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3370                                                  errmsg("cannot alter type \"%s\" because column \"%s\".\"%s\" uses it",
3371                                                                 origTypeName,
3372                                                                 RelationGetRelationName(rel),
3373                                                                 NameStr(att->attname))));
3374                 }
3375                 else if (OidIsValid(rel->rd_rel->reltype))
3376                 {
3377                         /*
3378                          * A view or composite type itself isn't a problem, but we must
3379                          * recursively check for indirect dependencies via its rowtype.
3380                          */
3381                         find_composite_type_dependencies(rel->rd_rel->reltype,
3382                                                                                          origTblName, origTypeName);
3383                 }
3384
3385                 relation_close(rel, AccessShareLock);
3386         }
3387
3388         systable_endscan(depScan);
3389
3390         relation_close(depRel, AccessShareLock);
3391
3392         /*
3393          * If there's an array type for the rowtype, must check for uses of it,
3394          * too.
3395          */
3396         arrayOid = get_array_type(typeOid);
3397         if (OidIsValid(arrayOid))
3398                 find_composite_type_dependencies(arrayOid, origTblName, origTypeName);
3399 }
3400
3401
3402 /*
3403  * ALTER TABLE ADD COLUMN
3404  *
3405  * Adds an additional attribute to a relation making the assumption that
3406  * CHECK, NOT NULL, and FOREIGN KEY constraints will be removed from the
3407  * AT_AddColumn AlterTableCmd by parse_utilcmd.c and added as independent
3408  * AlterTableCmd's.
3409  */
3410 static void
3411 ATPrepAddColumn(List **wqueue, Relation rel, bool recurse,
3412                                 AlterTableCmd *cmd)
3413 {
3414         /*
3415          * Recurse to add the column to child classes, if requested.
3416          *
3417          * We must recurse one level at a time, so that multiply-inheriting
3418          * children are visited the right number of times and end up with the
3419          * right attinhcount.
3420          */
3421         if (recurse)
3422         {
3423                 AlterTableCmd *childCmd = copyObject(cmd);
3424                 ColumnDef  *colDefChild = (ColumnDef *) childCmd->def;
3425
3426                 /* Child should see column as singly inherited */
3427                 colDefChild->inhcount = 1;
3428                 colDefChild->is_local = false;
3429
3430                 ATOneLevelRecursion(wqueue, rel, childCmd);
3431         }
3432         else
3433         {
3434                 /*
3435                  * If we are told not to recurse, there had better not be any child
3436                  * tables; else the addition would put them out of step.
3437                  */
3438                 if (find_inheritance_children(RelationGetRelid(rel)) != NIL)
3439                         ereport(ERROR,
3440                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
3441                                          errmsg("column must be added to child tables too")));
3442         }
3443 }
3444
3445 static void
3446 ATExecAddColumn(AlteredTableInfo *tab, Relation rel,
3447                                 ColumnDef *colDef)
3448 {
3449         Oid                     myrelid = RelationGetRelid(rel);
3450         Relation        pgclass,
3451                                 attrdesc;
3452         HeapTuple       reltup;
3453         HeapTuple       attributeTuple;
3454         Form_pg_attribute attribute;
3455         FormData_pg_attribute attributeD;
3456         int                     i;
3457         int                     minattnum,
3458                                 maxatts;
3459         HeapTuple       typeTuple;
3460         Oid                     typeOid;
3461         int32           typmod;
3462         Form_pg_type tform;
3463         Expr       *defval;
3464
3465         attrdesc = heap_open(AttributeRelationId, RowExclusiveLock);
3466
3467         /*
3468          * Are we adding the column to a recursion child?  If so, check whether to
3469          * merge with an existing definition for the column.
3470          */
3471         if (colDef->inhcount > 0)
3472         {
3473                 HeapTuple       tuple;
3474
3475                 /* Does child already have a column by this name? */
3476                 tuple = SearchSysCacheCopyAttName(myrelid, colDef->colname);
3477                 if (HeapTupleIsValid(tuple))
3478                 {
3479                         Form_pg_attribute childatt = (Form_pg_attribute) GETSTRUCT(tuple);
3480                         Oid                     ctypeId;
3481                         int32           ctypmod;
3482
3483                         /* Okay if child matches by type */
3484                         ctypeId = typenameTypeId(NULL, colDef->typename, &ctypmod);
3485                         if (ctypeId != childatt->atttypid ||
3486                                 ctypmod != childatt->atttypmod)
3487                                 ereport(ERROR,
3488                                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
3489                                                  errmsg("child table \"%s\" has different type for column \"%s\"",
3490                                                         RelationGetRelationName(rel), colDef->colname)));
3491
3492                         /* Bump the existing child att's inhcount */
3493                         childatt->attinhcount++;
3494                         simple_heap_update(attrdesc, &tuple->t_self, tuple);
3495                         CatalogUpdateIndexes(attrdesc, tuple);
3496
3497                         heap_freetuple(tuple);
3498
3499                         /* Inform the user about the merge */
3500                         ereport(NOTICE,
3501                           (errmsg("merging definition of column \"%s\" for child \"%s\"",
3502                                           colDef->colname, RelationGetRelationName(rel))));
3503
3504                         heap_close(attrdesc, RowExclusiveLock);
3505                         return;
3506                 }
3507         }
3508
3509         pgclass = heap_open(RelationRelationId, RowExclusiveLock);
3510
3511         reltup = SearchSysCacheCopy(RELOID,
3512                                                                 ObjectIdGetDatum(myrelid),
3513                                                                 0, 0, 0);
3514         if (!HeapTupleIsValid(reltup))
3515                 elog(ERROR, "cache lookup failed for relation %u", myrelid);
3516
3517         /*
3518          * this test is deliberately not attisdropped-aware, since if one tries to
3519          * add a column matching a dropped column name, it's gonna fail anyway.
3520          */
3521         if (SearchSysCacheExists(ATTNAME,
3522                                                          ObjectIdGetDatum(myrelid),
3523                                                          PointerGetDatum(colDef->colname),
3524                                                          0, 0))
3525                 ereport(ERROR,
3526                                 (errcode(ERRCODE_DUPLICATE_COLUMN),
3527                                  errmsg("column \"%s\" of relation \"%s\" already exists",
3528                                                 colDef->colname, RelationGetRelationName(rel))));
3529
3530         minattnum = ((Form_pg_class) GETSTRUCT(reltup))->relnatts;
3531         maxatts = minattnum + 1;
3532         if (maxatts > MaxHeapAttributeNumber)
3533                 ereport(ERROR,
3534                                 (errcode(ERRCODE_TOO_MANY_COLUMNS),
3535                                  errmsg("tables can have at most %d columns",
3536                                                 MaxHeapAttributeNumber)));
3537         i = minattnum + 1;
3538
3539         typeTuple = typenameType(NULL, colDef->typename, &typmod);
3540         tform = (Form_pg_type) GETSTRUCT(typeTuple);
3541         typeOid = HeapTupleGetOid(typeTuple);
3542
3543         /* make sure datatype is legal for a column */
3544         CheckAttributeType(colDef->colname, typeOid);
3545
3546         attributeTuple = heap_addheader(Natts_pg_attribute,
3547                                                                         false,
3548                                                                         ATTRIBUTE_TUPLE_SIZE,
3549                                                                         (void *) &attributeD);
3550
3551         attribute = (Form_pg_attribute) GETSTRUCT(attributeTuple);
3552
3553         attribute->attrelid = myrelid;
3554         namestrcpy(&(attribute->attname), colDef->colname);
3555         attribute->atttypid = typeOid;
3556         attribute->attstattarget = -1;
3557         attribute->attlen = tform->typlen;
3558         attribute->attcacheoff = -1;
3559         attribute->atttypmod = typmod;
3560         attribute->attnum = i;
3561         attribute->attbyval = tform->typbyval;
3562         attribute->attndims = list_length(colDef->typename->arrayBounds);
3563         attribute->attstorage = tform->typstorage;
3564         attribute->attalign = tform->typalign;
3565         attribute->attnotnull = colDef->is_not_null;
3566         attribute->atthasdef = false;
3567         attribute->attisdropped = false;
3568         attribute->attislocal = colDef->is_local;
3569         attribute->attinhcount = colDef->inhcount;
3570
3571         ReleaseSysCache(typeTuple);
3572
3573         simple_heap_insert(attrdesc, attributeTuple);
3574
3575         /* Update indexes on pg_attribute */
3576         CatalogUpdateIndexes(attrdesc, attributeTuple);
3577
3578         heap_close(attrdesc, RowExclusiveLock);
3579
3580         /*
3581          * Update number of attributes in pg_class tuple
3582          */
3583         ((Form_pg_class) GETSTRUCT(reltup))->relnatts = maxatts;
3584
3585         simple_heap_update(pgclass, &reltup->t_self, reltup);
3586
3587         /* keep catalog indexes current */
3588         CatalogUpdateIndexes(pgclass, reltup);
3589
3590         heap_freetuple(reltup);
3591
3592         heap_close(pgclass, RowExclusiveLock);
3593
3594         /* Make the attribute's catalog entry visible */
3595         CommandCounterIncrement();
3596
3597         /*
3598          * Store the DEFAULT, if any, in the catalogs
3599          */
3600         if (colDef->raw_default)
3601         {
3602                 RawColumnDefault *rawEnt;
3603
3604                 rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
3605                 rawEnt->attnum = attribute->attnum;
3606                 rawEnt->raw_default = copyObject(colDef->raw_default);
3607
3608                 /*
3609                  * This function is intended for CREATE TABLE, so it processes a
3610                  * _list_ of defaults, but we just do one.
3611                  */
3612                 AddRelationNewConstraints(rel, list_make1(rawEnt), NIL, false, true);
3613
3614                 /* Make the additional catalog changes visible */
3615                 CommandCounterIncrement();
3616         }
3617
3618         /*
3619          * Tell Phase 3 to fill in the default expression, if there is one.
3620          *
3621          * If there is no default, Phase 3 doesn't have to do anything, because
3622          * that effectively means that the default is NULL.  The heap tuple access
3623          * routines always check for attnum > # of attributes in tuple, and return
3624          * NULL if so, so without any modification of the tuple data we will get
3625          * the effect of NULL values in the new column.
3626          *
3627          * An exception occurs when the new column is of a domain type: the domain
3628          * might have a NOT NULL constraint, or a check constraint that indirectly
3629          * rejects nulls.  If there are any domain constraints then we construct
3630          * an explicit NULL default value that will be passed through
3631          * CoerceToDomain processing.  (This is a tad inefficient, since it causes
3632          * rewriting the table which we really don't have to do, but the present
3633          * design of domain processing doesn't offer any simple way of checking
3634          * the constraints more directly.)
3635          *
3636          * Note: we use build_column_default, and not just the cooked default
3637          * returned by AddRelationNewConstraints, so that the right thing happens
3638          * when a datatype's default applies.
3639          */
3640         defval = (Expr *) build_column_default(rel, attribute->attnum);
3641
3642         if (!defval && GetDomainConstraints(typeOid) != NIL)
3643         {
3644                 Oid                     baseTypeId;
3645                 int32           baseTypeMod;
3646
3647                 baseTypeMod = typmod;
3648                 baseTypeId = getBaseTypeAndTypmod(typeOid, &baseTypeMod);
3649                 defval = (Expr *) makeNullConst(baseTypeId, baseTypeMod);
3650                 defval = (Expr *) coerce_to_target_type(NULL,
3651                                                                                                 (Node *) defval,
3652                                                                                                 baseTypeId,
3653                                                                                                 typeOid,
3654                                                                                                 typmod,
3655                                                                                                 COERCION_ASSIGNMENT,
3656                                                                                                 COERCE_IMPLICIT_CAST,
3657                                                                                                 -1);
3658                 if (defval == NULL)             /* should not happen */
3659                         elog(ERROR, "failed to coerce base type to domain");
3660         }
3661
3662         if (defval)
3663         {
3664                 NewColumnValue *newval;
3665
3666                 newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
3667                 newval->attnum = attribute->attnum;
3668                 newval->expr = defval;
3669
3670                 tab->newvals = lappend(tab->newvals, newval);
3671         }
3672
3673         /*
3674          * If the new column is NOT NULL, tell Phase 3 it needs to test that.
3675          */
3676         tab->new_notnull |= colDef->is_not_null;
3677
3678         /*
3679          * Add needed dependency entries for the new column.
3680          */
3681         add_column_datatype_dependency(myrelid, i, attribute->atttypid);
3682 }
3683
3684 /*
3685  * Install a column's dependency on its datatype.
3686  */
3687 static void
3688 add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid)
3689 {
3690         ObjectAddress myself,
3691                                 referenced;
3692
3693         myself.classId = RelationRelationId;
3694         myself.objectId = relid;
3695         myself.objectSubId = attnum;
3696         referenced.classId = TypeRelationId;
3697         referenced.objectId = typid;
3698         referenced.objectSubId = 0;
3699         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
3700 }
3701
3702 /*
3703  * ALTER TABLE ALTER COLUMN DROP NOT NULL
3704  */
3705 static void
3706 ATExecDropNotNull(Relation rel, const char *colName)
3707 {
3708         HeapTuple       tuple;
3709         AttrNumber      attnum;
3710         Relation        attr_rel;
3711         List       *indexoidlist;
3712         ListCell   *indexoidscan;
3713
3714         /*
3715          * lookup the attribute
3716          */
3717         attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
3718
3719         tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
3720
3721         if (!HeapTupleIsValid(tuple))
3722                 ereport(ERROR,
3723                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3724                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3725                                                 colName, RelationGetRelationName(rel))));
3726
3727         attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
3728
3729         /* Prevent them from altering a system attribute */
3730         if (attnum <= 0)
3731                 ereport(ERROR,
3732                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3733                                  errmsg("cannot alter system column \"%s\"",
3734                                                 colName)));
3735
3736         /*
3737          * Check that the attribute is not in a primary key
3738          */
3739
3740         /* Loop over all indexes on the relation */
3741         indexoidlist = RelationGetIndexList(rel);
3742
3743         foreach(indexoidscan, indexoidlist)
3744         {
3745                 Oid                     indexoid = lfirst_oid(indexoidscan);
3746                 HeapTuple       indexTuple;
3747                 Form_pg_index indexStruct;
3748                 int                     i;
3749
3750                 indexTuple = SearchSysCache(INDEXRELID,
3751                                                                         ObjectIdGetDatum(indexoid),
3752                                                                         0, 0, 0);
3753                 if (!HeapTupleIsValid(indexTuple))
3754                         elog(ERROR, "cache lookup failed for index %u", indexoid);
3755                 indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
3756
3757                 /* If the index is not a primary key, skip the check */
3758                 if (indexStruct->indisprimary)
3759                 {
3760                         /*
3761                          * Loop over each attribute in the primary key and see if it
3762                          * matches the to-be-altered attribute
3763                          */
3764                         for (i = 0; i < indexStruct->indnatts; i++)
3765                         {
3766                                 if (indexStruct->indkey.values[i] == attnum)
3767                                         ereport(ERROR,
3768                                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
3769                                                          errmsg("column \"%s\" is in a primary key",
3770                                                                         colName)));
3771                         }
3772                 }
3773
3774                 ReleaseSysCache(indexTuple);
3775         }
3776
3777         list_free(indexoidlist);
3778
3779         /*
3780          * Okay, actually perform the catalog change ... if needed
3781          */
3782         if (((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull)
3783         {
3784                 ((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = FALSE;
3785
3786                 simple_heap_update(attr_rel, &tuple->t_self, tuple);
3787
3788                 /* keep the system catalog indexes current */
3789                 CatalogUpdateIndexes(attr_rel, tuple);
3790         }
3791
3792         heap_close(attr_rel, RowExclusiveLock);
3793 }
3794
3795 /*
3796  * ALTER TABLE ALTER COLUMN SET NOT NULL
3797  */
3798 static void
3799 ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
3800                                  const char *colName)
3801 {
3802         HeapTuple       tuple;
3803         AttrNumber      attnum;
3804         Relation        attr_rel;
3805
3806         /*
3807          * lookup the attribute
3808          */
3809         attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
3810
3811         tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
3812
3813         if (!HeapTupleIsValid(tuple))
3814                 ereport(ERROR,
3815                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3816                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3817                                                 colName, RelationGetRelationName(rel))));
3818
3819         attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
3820
3821         /* Prevent them from altering a system attribute */
3822         if (attnum <= 0)
3823                 ereport(ERROR,
3824                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3825                                  errmsg("cannot alter system column \"%s\"",
3826                                                 colName)));
3827
3828         /*
3829          * Okay, actually perform the catalog change ... if needed
3830          */
3831         if (!((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull)
3832         {
3833                 ((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = TRUE;
3834
3835                 simple_heap_update(attr_rel, &tuple->t_self, tuple);
3836
3837                 /* keep the system catalog indexes current */
3838                 CatalogUpdateIndexes(attr_rel, tuple);
3839
3840                 /* Tell Phase 3 it needs to test the constraint */
3841                 tab->new_notnull = true;
3842         }
3843
3844         heap_close(attr_rel, RowExclusiveLock);
3845 }
3846
3847 /*
3848  * ALTER TABLE ALTER COLUMN SET/DROP DEFAULT
3849  */
3850 static void
3851 ATExecColumnDefault(Relation rel, const char *colName,
3852                                         Node *newDefault)
3853 {
3854         AttrNumber      attnum;
3855
3856         /*
3857          * get the number of the attribute
3858          */
3859         attnum = get_attnum(RelationGetRelid(rel), colName);
3860         if (attnum == InvalidAttrNumber)
3861                 ereport(ERROR,
3862                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3863                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3864                                                 colName, RelationGetRelationName(rel))));
3865
3866         /* Prevent them from altering a system attribute */
3867         if (attnum <= 0)
3868                 ereport(ERROR,
3869                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3870                                  errmsg("cannot alter system column \"%s\"",
3871                                                 colName)));
3872
3873         /*
3874          * Remove any old default for the column.  We use RESTRICT here for
3875          * safety, but at present we do not expect anything to depend on the
3876          * default.
3877          */
3878         RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, false);
3879
3880         if (newDefault)
3881         {
3882                 /* SET DEFAULT */
3883                 RawColumnDefault *rawEnt;
3884
3885                 rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
3886                 rawEnt->attnum = attnum;
3887                 rawEnt->raw_default = newDefault;
3888
3889                 /*
3890                  * This function is intended for CREATE TABLE, so it processes a
3891                  * _list_ of defaults, but we just do one.
3892                  */
3893                 AddRelationNewConstraints(rel, list_make1(rawEnt), NIL, false, true);
3894         }
3895 }
3896
3897 /*
3898  * ALTER TABLE ALTER COLUMN SET STATISTICS
3899  */
3900 static void
3901 ATPrepSetStatistics(Relation rel, const char *colName, Node *flagValue)
3902 {
3903         /*
3904          * We do our own permission checking because (a) we want to allow SET
3905          * STATISTICS on indexes (for expressional index columns), and (b) we want
3906          * to allow SET STATISTICS on system catalogs without requiring
3907          * allowSystemTableMods to be turned on.
3908          */
3909         if (rel->rd_rel->relkind != RELKIND_RELATION &&
3910                 rel->rd_rel->relkind != RELKIND_INDEX)
3911                 ereport(ERROR,
3912                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
3913                                  errmsg("\"%s\" is not a table or index",
3914                                                 RelationGetRelationName(rel))));
3915
3916         /* Permissions checks */
3917         if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
3918                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
3919                                            RelationGetRelationName(rel));
3920 }
3921
3922 static void
3923 ATExecSetStatistics(Relation rel, const char *colName, Node *newValue)
3924 {
3925         int                     newtarget;
3926         Relation        attrelation;
3927         HeapTuple       tuple;
3928         Form_pg_attribute attrtuple;
3929
3930         Assert(IsA(newValue, Integer));
3931         newtarget = intVal(newValue);
3932
3933         /*
3934          * Limit target to a sane range
3935          */
3936         if (newtarget < -1)
3937         {
3938                 ereport(ERROR,
3939                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
3940                                  errmsg("statistics target %d is too low",
3941                                                 newtarget)));
3942         }
3943         else if (newtarget > 1000)
3944         {
3945                 newtarget = 1000;
3946                 ereport(WARNING,
3947                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
3948                                  errmsg("lowering statistics target to %d",
3949                                                 newtarget)));
3950         }
3951
3952         attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
3953
3954         tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
3955
3956         if (!HeapTupleIsValid(tuple))
3957                 ereport(ERROR,
3958                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3959                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3960                                                 colName, RelationGetRelationName(rel))));
3961         attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
3962
3963         if (attrtuple->attnum <= 0)
3964                 ereport(ERROR,
3965                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3966                                  errmsg("cannot alter system column \"%s\"",
3967                                                 colName)));
3968
3969         attrtuple->attstattarget = newtarget;
3970
3971         simple_heap_update(attrelation, &tuple->t_self, tuple);
3972
3973         /* keep system catalog indexes current */
3974         CatalogUpdateIndexes(attrelation, tuple);
3975
3976         heap_freetuple(tuple);
3977
3978         heap_close(attrelation, RowExclusiveLock);
3979 }
3980
3981 /*
3982  * ALTER TABLE ALTER COLUMN SET STORAGE
3983  */
3984 static void
3985 ATExecSetStorage(Relation rel, const char *colName, Node *newValue)
3986 {
3987         char       *storagemode;
3988         char            newstorage;
3989         Relation        attrelation;
3990         HeapTuple       tuple;
3991         Form_pg_attribute attrtuple;
3992
3993         Assert(IsA(newValue, String));
3994         storagemode = strVal(newValue);
3995
3996         if (pg_strcasecmp(storagemode, "plain") == 0)
3997                 newstorage = 'p';
3998         else if (pg_strcasecmp(storagemode, "external") == 0)
3999                 newstorage = 'e';
4000         else if (pg_strcasecmp(storagemode, "extended") == 0)
4001                 newstorage = 'x';
4002         else if (pg_strcasecmp(storagemode, "main") == 0)
4003                 newstorage = 'm';
4004         else
4005         {
4006                 ereport(ERROR,
4007                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
4008                                  errmsg("invalid storage type \"%s\"",
4009                                                 storagemode)));
4010                 newstorage = 0;                 /* keep compiler quiet */
4011         }
4012
4013         attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
4014
4015         tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
4016
4017         if (!HeapTupleIsValid(tuple))
4018                 ereport(ERROR,
4019                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
4020                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
4021                                                 colName, RelationGetRelationName(rel))));
4022         attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
4023
4024         if (attrtuple->attnum <= 0)
4025                 ereport(ERROR,
4026                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4027                                  errmsg("cannot alter system column \"%s\"",
4028                                                 colName)));
4029
4030         /*
4031          * safety check: do not allow toasted storage modes unless column datatype
4032          * is TOAST-aware.
4033          */
4034         if (newstorage == 'p' || TypeIsToastable(attrtuple->atttypid))
4035                 attrtuple->attstorage = newstorage;
4036         else
4037                 ereport(ERROR,
4038                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4039                                  errmsg("column data type %s can only have storage PLAIN",
4040                                                 format_type_be(attrtuple->atttypid))));
4041
4042         simple_heap_update(attrelation, &tuple->t_self, tuple);
4043
4044         /* keep system catalog indexes current */
4045         CatalogUpdateIndexes(attrelation, tuple);
4046
4047         heap_freetuple(tuple);
4048
4049         heap_close(attrelation, RowExclusiveLock);
4050 }
4051
4052
4053 /*
4054  * ALTER TABLE DROP COLUMN
4055  *
4056  * DROP COLUMN cannot use the normal ALTER TABLE recursion mechanism,
4057  * because we have to decide at runtime whether to recurse or not depending
4058  * on whether attinhcount goes to zero or not.  (We can't check this in a
4059  * static pre-pass because it won't handle multiple inheritance situations
4060  * correctly.)  Since DROP COLUMN doesn't need to create any work queue
4061  * entries for Phase 3, it's okay to recurse internally in this routine
4062  * without considering the work queue.
4063  */
4064 static void
4065 ATExecDropColumn(Relation rel, const char *colName,
4066                                  DropBehavior behavior,
4067                                  bool recurse, bool recursing)
4068 {
4069         HeapTuple       tuple;
4070         Form_pg_attribute targetatt;
4071         AttrNumber      attnum;
4072         List       *children;
4073         ObjectAddress object;
4074
4075         /* At top level, permission check was done in ATPrepCmd, else do it */
4076         if (recursing)
4077                 ATSimplePermissions(rel, false);
4078
4079         /*
4080          * get the number of the attribute
4081          */
4082         tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
4083         if (!HeapTupleIsValid(tuple))
4084                 ereport(ERROR,
4085                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
4086                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
4087                                                 colName, RelationGetRelationName(rel))));
4088         targetatt = (Form_pg_attribute) GETSTRUCT(tuple);
4089
4090         attnum = targetatt->attnum;
4091
4092         /* Can't drop a system attribute, except OID */
4093         if (attnum <= 0 && attnum != ObjectIdAttributeNumber)
4094                 ereport(ERROR,
4095                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4096                                  errmsg("cannot drop system column \"%s\"",
4097                                                 colName)));
4098
4099         /* Don't drop inherited columns */
4100         if (targetatt->attinhcount > 0 && !recursing)
4101                 ereport(ERROR,
4102                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
4103                                  errmsg("cannot drop inherited column \"%s\"",
4104                                                 colName)));
4105
4106         ReleaseSysCache(tuple);
4107
4108         /*
4109          * Propagate to children as appropriate.  Unlike most other ALTER
4110          * routines, we have to do this one level of recursion at a time; we can't
4111          * use find_all_inheritors to do it in one pass.
4112          */
4113         children = find_inheritance_children(RelationGetRelid(rel));
4114
4115         if (children)
4116         {
4117                 Relation        attr_rel;
4118                 ListCell   *child;
4119
4120                 attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
4121                 foreach(child, children)
4122                 {
4123                         Oid                     childrelid = lfirst_oid(child);
4124                         Relation        childrel;
4125                         Form_pg_attribute childatt;
4126
4127                         childrel = heap_open(childrelid, AccessExclusiveLock);
4128                         CheckTableNotInUse(childrel, "ALTER TABLE");
4129
4130                         tuple = SearchSysCacheCopyAttName(childrelid, colName);
4131                         if (!HeapTupleIsValid(tuple))           /* shouldn't happen */
4132                                 elog(ERROR, "cache lookup failed for attribute \"%s\" of relation %u",
4133                                          colName, childrelid);
4134                         childatt = (Form_pg_attribute) GETSTRUCT(tuple);
4135
4136                         if (childatt->attinhcount <= 0)         /* shouldn't happen */
4137                                 elog(ERROR, "relation %u has non-inherited attribute \"%s\"",
4138                                          childrelid, colName);
4139
4140                         if (recurse)
4141                         {
4142                                 /*
4143                                  * If the child column has other definition sources, just
4144                                  * decrement its inheritance count; if not, recurse to delete
4145                                  * it.
4146                                  */
4147                                 if (childatt->attinhcount == 1 && !childatt->attislocal)
4148                                 {
4149                                         /* Time to delete this child column, too */
4150                                         ATExecDropColumn(childrel, colName, behavior, true, true);
4151                                 }
4152                                 else
4153                                 {
4154                                         /* Child column must survive my deletion */
4155                                         childatt->attinhcount--;
4156
4157                                         simple_heap_update(attr_rel, &tuple->t_self, tuple);
4158
4159                                         /* keep the system catalog indexes current */
4160                                         CatalogUpdateIndexes(attr_rel, tuple);
4161
4162                                         /* Make update visible */
4163                                         CommandCounterIncrement();
4164                                 }
4165                         }
4166                         else
4167                         {
4168                                 /*
4169                                  * If we were told to drop ONLY in this table (no recursion),
4170                                  * we need to mark the inheritors' attributes as locally
4171                                  * defined rather than inherited.
4172                                  */
4173                                 childatt->attinhcount--;
4174                                 childatt->attislocal = true;
4175
4176                                 simple_heap_update(attr_rel, &tuple->t_self, tuple);
4177
4178                                 /* keep the system catalog indexes current */
4179                                 CatalogUpdateIndexes(attr_rel, tuple);
4180
4181                                 /* Make update visible */
4182                                 CommandCounterIncrement();
4183                         }
4184
4185                         heap_freetuple(tuple);
4186
4187                         heap_close(childrel, NoLock);
4188                 }
4189                 heap_close(attr_rel, RowExclusiveLock);
4190         }
4191
4192         /*
4193          * Perform the actual column deletion
4194          */
4195         object.classId = RelationRelationId;
4196         object.objectId = RelationGetRelid(rel);
4197         object.objectSubId = attnum;
4198
4199         performDeletion(&object, behavior);
4200
4201         /*
4202          * If we dropped the OID column, must adjust pg_class.relhasoids
4203          */
4204         if (attnum == ObjectIdAttributeNumber)
4205         {
4206                 Relation        class_rel;
4207                 Form_pg_class tuple_class;
4208
4209                 class_rel = heap_open(RelationRelationId, RowExclusiveLock);
4210
4211                 tuple = SearchSysCacheCopy(RELOID,
4212                                                                    ObjectIdGetDatum(RelationGetRelid(rel)),
4213                                                                    0, 0, 0);
4214                 if (!HeapTupleIsValid(tuple))
4215                         elog(ERROR, "cache lookup failed for relation %u",
4216                                  RelationGetRelid(rel));
4217                 tuple_class = (Form_pg_class) GETSTRUCT(tuple);
4218
4219                 tuple_class->relhasoids = false;
4220                 simple_heap_update(class_rel, &tuple->t_self, tuple);
4221
4222                 /* Keep the catalog indexes up to date */
4223                 CatalogUpdateIndexes(class_rel, tuple);
4224
4225                 heap_close(class_rel, RowExclusiveLock);
4226         }
4227 }
4228
4229 /*
4230  * ALTER TABLE ADD INDEX
4231  *
4232  * There is no such command in the grammar, but parse_utilcmd.c converts
4233  * UNIQUE and PRIMARY KEY constraints into AT_AddIndex subcommands.  This lets
4234  * us schedule creation of the index at the appropriate time during ALTER.
4235  */
4236 static void
4237 ATExecAddIndex(AlteredTableInfo *tab, Relation rel,
4238                            IndexStmt *stmt, bool is_rebuild)
4239 {
4240         bool            check_rights;
4241         bool            skip_build;
4242         bool            quiet;
4243
4244         Assert(IsA(stmt, IndexStmt));
4245
4246         /* suppress schema rights check when rebuilding existing index */
4247         check_rights = !is_rebuild;
4248         /* skip index build if phase 3 will have to rewrite table anyway */
4249         skip_build = (tab->newvals != NIL);
4250         /* suppress notices when rebuilding existing index */
4251         quiet = is_rebuild;
4252
4253         /* The IndexStmt has already been through transformIndexStmt */
4254
4255         DefineIndex(stmt->relation, /* relation */
4256                                 stmt->idxname,  /* index name */
4257                                 InvalidOid,             /* no predefined OID */
4258                                 stmt->accessMethod,             /* am name */
4259                                 stmt->tableSpace,
4260                                 stmt->indexParams,              /* parameters */
4261                                 (Expr *) stmt->whereClause,
4262                                 stmt->options,
4263                                 stmt->unique,
4264                                 stmt->primary,
4265                                 stmt->isconstraint,
4266                                 true,                   /* is_alter_table */
4267                                 check_rights,
4268                                 skip_build,
4269                                 quiet,
4270                                 false);
4271 }
4272
4273 /*
4274  * ALTER TABLE ADD CONSTRAINT
4275  */
4276 static void
4277 ATExecAddConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
4278                                         Node *newConstraint, bool recurse)
4279 {
4280         switch (nodeTag(newConstraint))
4281         {
4282                 case T_Constraint:
4283                         {
4284                                 Constraint *constr = (Constraint *) newConstraint;
4285
4286                                 /*
4287                                  * Currently, we only expect to see CONSTR_CHECK nodes
4288                                  * arriving here (see the preprocessing done in
4289                                  * parse_utilcmd.c).  Use a switch anyway to make it easier to
4290                                  * add more code later.
4291                                  */
4292                                 switch (constr->contype)
4293                                 {
4294                                         case CONSTR_CHECK:
4295                                                 ATAddCheckConstraint(wqueue, tab, rel,
4296                                                                                          constr, recurse, false);
4297                                                 break;
4298                                         default:
4299                                                 elog(ERROR, "unrecognized constraint type: %d",
4300                                                          (int) constr->contype);
4301                                 }
4302                                 break;
4303                         }
4304                 case T_FkConstraint:
4305                         {
4306                                 FkConstraint *fkconstraint = (FkConstraint *) newConstraint;
4307
4308                                 /*
4309                                  * Note that we currently never recurse for FK constraints,
4310                                  * so the "recurse" flag is silently ignored.
4311                                  *
4312                                  * Assign or validate constraint name
4313                                  */
4314                                 if (fkconstraint->constr_name)
4315                                 {
4316                                         if (ConstraintNameIsUsed(CONSTRAINT_RELATION,
4317                                                                                          RelationGetRelid(rel),
4318                                                                                          RelationGetNamespace(rel),
4319                                                                                          fkconstraint->constr_name))
4320                                                 ereport(ERROR,
4321                                                                 (errcode(ERRCODE_DUPLICATE_OBJECT),
4322                                                                  errmsg("constraint \"%s\" for relation \"%s\" already exists",
4323                                                                                 fkconstraint->constr_name,
4324                                                                                 RelationGetRelationName(rel))));
4325                                 }
4326                                 else
4327                                         fkconstraint->constr_name =
4328                                                 ChooseConstraintName(RelationGetRelationName(rel),
4329                                                                         strVal(linitial(fkconstraint->fk_attrs)),
4330                                                                                          "fkey",
4331                                                                                          RelationGetNamespace(rel),
4332                                                                                          NIL);
4333
4334                                 ATAddForeignKeyConstraint(tab, rel, fkconstraint);
4335
4336                                 break;
4337                         }
4338                 default:
4339                         elog(ERROR, "unrecognized node type: %d",
4340                                  (int) nodeTag(newConstraint));
4341         }
4342 }
4343
4344 /*
4345  * Add a check constraint to a single table and its children
4346  *
4347  * Subroutine for ATExecAddConstraint.
4348  *
4349  * We must recurse to child tables during execution, rather than using
4350  * ALTER TABLE's normal prep-time recursion.  The reason is that all the
4351  * constraints *must* be given the same name, else they won't be seen as
4352  * related later.  If the user didn't explicitly specify a name, then
4353  * AddRelationNewConstraints would normally assign different names to the
4354  * child constraints.  To fix that, we must capture the name assigned at
4355  * the parent table and pass that down.
4356  */
4357 static void
4358 ATAddCheckConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
4359                                          Constraint *constr, bool recurse, bool recursing)
4360 {
4361         List       *newcons;
4362         ListCell   *lcon;
4363         List       *children;
4364         ListCell   *child;
4365
4366         /* At top level, permission check was done in ATPrepCmd, else do it */
4367         if (recursing)
4368                 ATSimplePermissions(rel, false);
4369
4370         /*
4371          * Call AddRelationNewConstraints to do the work, making sure it works on
4372          * a copy of the Constraint so transformExpr can't modify the original.
4373          * It returns a list of cooked constraints.
4374          *
4375          * If the constraint ends up getting merged with a pre-existing one, it's
4376          * omitted from the returned list, which is what we want: we do not need
4377          * to do any validation work.  That can only happen at child tables,
4378          * though, since we disallow merging at the top level.
4379          */
4380         newcons = AddRelationNewConstraints(rel, NIL,
4381                                                                                 list_make1(copyObject(constr)),
4382                                                                                 recursing, !recursing);
4383
4384         /* Add each constraint to Phase 3's queue */
4385         foreach(lcon, newcons)
4386         {
4387                 CookedConstraint *ccon = (CookedConstraint *) lfirst(lcon);
4388                 NewConstraint *newcon;
4389
4390                 newcon = (NewConstraint *) palloc0(sizeof(NewConstraint));
4391                 newcon->name = ccon->name;
4392                 newcon->contype = ccon->contype;
4393                 /* ExecQual wants implicit-AND format */
4394                 newcon->qual = (Node *) make_ands_implicit((Expr *) ccon->expr);
4395
4396                 tab->constraints = lappend(tab->constraints, newcon);
4397
4398                 /* Save the actually assigned name if it was defaulted */
4399                 if (constr->name == NULL)
4400                         constr->name = ccon->name;
4401         }
4402
4403         /* At this point we must have a locked-down name to use */
4404         Assert(constr->name != NULL);
4405
4406         /* Advance command counter in case same table is visited multiple times */
4407         CommandCounterIncrement();
4408
4409         /*
4410          * Propagate to children as appropriate.  Unlike most other ALTER
4411          * routines, we have to do this one level of recursion at a time; we can't
4412          * use find_all_inheritors to do it in one pass.
4413          */
4414         children = find_inheritance_children(RelationGetRelid(rel));
4415
4416         /*
4417          * If we are told not to recurse, there had better not be any child
4418          * tables; else the addition would put them out of step.
4419          */
4420         if (children && !recurse)
4421                 ereport(ERROR,
4422                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
4423                                  errmsg("constraint must be added to child tables too")));
4424
4425         foreach(child, children)
4426         {
4427                 Oid                     childrelid = lfirst_oid(child);
4428                 Relation        childrel;
4429                 AlteredTableInfo *childtab;
4430
4431                 childrel = heap_open(childrelid, AccessExclusiveLock);
4432                 CheckTableNotInUse(childrel, "ALTER TABLE");
4433
4434                 /* Find or create work queue entry for this table */
4435                 childtab = ATGetQueueEntry(wqueue, childrel);
4436
4437                 /* Recurse to child */
4438                 ATAddCheckConstraint(wqueue, childtab, childrel,
4439                                                          constr, recurse, true);
4440
4441                 heap_close(childrel, NoLock);
4442         }
4443 }
4444
4445 /*
4446  * Add a foreign-key constraint to a single table
4447  *
4448  * Subroutine for ATExecAddConstraint.  Must already hold exclusive
4449  * lock on the rel, and have done appropriate validity/permissions checks
4450  * for it.
4451  */
4452 static void
4453 ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel,
4454                                                   FkConstraint *fkconstraint)
4455 {
4456         Relation        pkrel;
4457         AclResult       aclresult;
4458         int16           pkattnum[INDEX_MAX_KEYS];
4459         int16           fkattnum[INDEX_MAX_KEYS];
4460         Oid                     pktypoid[INDEX_MAX_KEYS];
4461         Oid                     fktypoid[INDEX_MAX_KEYS];
4462         Oid                     opclasses[INDEX_MAX_KEYS];
4463         Oid                     pfeqoperators[INDEX_MAX_KEYS];
4464         Oid                     ppeqoperators[INDEX_MAX_KEYS];
4465         Oid                     ffeqoperators[INDEX_MAX_KEYS];
4466         int                     i;
4467         int                     numfks,
4468                                 numpks;
4469         Oid                     indexOid;
4470         Oid                     constrOid;
4471
4472         /*
4473          * Grab an exclusive lock on the pk table, so that someone doesn't delete
4474          * rows out from under us. (Although a lesser lock would do for that
4475          * purpose, we'll need exclusive lock anyway to add triggers to the pk
4476          * table; trying to start with a lesser lock will just create a risk of
4477          * deadlock.)
4478          */
4479         pkrel = heap_openrv(fkconstraint->pktable, AccessExclusiveLock);
4480
4481         /*
4482          * Validity and permissions checks
4483          *
4484          * Note: REFERENCES permissions checks are redundant with CREATE TRIGGER,
4485          * but we may as well error out sooner instead of later.
4486          */
4487         if (pkrel->rd_rel->relkind != RELKIND_RELATION)
4488                 ereport(ERROR,
4489                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
4490                                  errmsg("referenced relation \"%s\" is not a table",
4491                                                 RelationGetRelationName(pkrel))));
4492
4493         aclresult = pg_class_aclcheck(RelationGetRelid(pkrel), GetUserId(),
4494                                                                   ACL_REFERENCES);
4495         if (aclresult != ACLCHECK_OK)
4496                 aclcheck_error(aclresult, ACL_KIND_CLASS,
4497                                            RelationGetRelationName(pkrel));
4498
4499         if (!allowSystemTableMods && IsSystemRelation(pkrel))
4500                 ereport(ERROR,
4501                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
4502                                  errmsg("permission denied: \"%s\" is a system catalog",
4503                                                 RelationGetRelationName(pkrel))));
4504
4505         aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
4506                                                                   ACL_REFERENCES);
4507         if (aclresult != ACLCHECK_OK)
4508                 aclcheck_error(aclresult, ACL_KIND_CLASS,
4509                                            RelationGetRelationName(rel));
4510
4511         /*
4512          * Disallow reference from permanent table to temp table or vice versa.
4513          * (The ban on perm->temp is for fairly obvious reasons.  The ban on
4514          * temp->perm is because other backends might need to run the RI triggers
4515          * on the perm table, but they can't reliably see tuples the owning
4516          * backend has created in the temp table, because non-shared buffers are
4517          * used for temp tables.)
4518          */
4519         if (isTempNamespace(RelationGetNamespace(pkrel)))
4520         {
4521                 if (!isTempNamespace(RelationGetNamespace(rel)))
4522                         ereport(ERROR,
4523                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
4524                                          errmsg("cannot reference temporary table from permanent table constraint")));
4525         }
4526         else
4527         {
4528                 if (isTempNamespace(RelationGetNamespace(rel)))
4529                         ereport(ERROR,
4530                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
4531                                          errmsg("cannot reference permanent table from temporary table constraint")));
4532         }
4533
4534         /*
4535          * Look up the referencing attributes to make sure they exist, and record
4536          * their attnums and type OIDs.
4537          */
4538         MemSet(pkattnum, 0, sizeof(pkattnum));
4539         MemSet(fkattnum, 0, sizeof(fkattnum));
4540         MemSet(pktypoid, 0, sizeof(pktypoid));
4541         MemSet(fktypoid, 0, sizeof(fktypoid));
4542         MemSet(opclasses, 0, sizeof(opclasses));
4543         MemSet(pfeqoperators, 0, sizeof(pfeqoperators));
4544         MemSet(ppeqoperators, 0, sizeof(ppeqoperators));
4545         MemSet(ffeqoperators, 0, sizeof(ffeqoperators));
4546
4547         numfks = transformColumnNameList(RelationGetRelid(rel),
4548                                                                          fkconstraint->fk_attrs,
4549                                                                          fkattnum, fktypoid);
4550
4551         /*
4552          * If the attribute list for the referenced table was omitted, lookup the
4553          * definition of the primary key and use it.  Otherwise, validate the
4554          * supplied attribute list.  In either case, discover the index OID and
4555          * index opclasses, and the attnums and type OIDs of the attributes.
4556          */
4557         if (fkconstraint->pk_attrs == NIL)
4558         {
4559                 numpks = transformFkeyGetPrimaryKey(pkrel, &indexOid,
4560                                                                                         &fkconstraint->pk_attrs,
4561                                                                                         pkattnum, pktypoid,
4562                                                                                         opclasses);
4563         }
4564         else
4565         {
4566                 numpks = transformColumnNameList(RelationGetRelid(pkrel),
4567                                                                                  fkconstraint->pk_attrs,
4568                                                                                  pkattnum, pktypoid);
4569                 /* Look for an index matching the column list */
4570                 indexOid = transformFkeyCheckAttrs(pkrel, numpks, pkattnum,
4571                                                                                    opclasses);
4572         }
4573
4574         /*
4575          * Look up the equality operators to use in the constraint.
4576          *
4577          * Note that we have to be careful about the difference between the actual
4578          * PK column type and the opclass' declared input type, which might be
4579          * only binary-compatible with it.      The declared opcintype is the right
4580          * thing to probe pg_amop with.
4581          */
4582         if (numfks != numpks)
4583                 ereport(ERROR,
4584                                 (errcode(ERRCODE_INVALID_FOREIGN_KEY),
4585                                  errmsg("number of referencing and referenced columns for foreign key disagree")));
4586
4587         for (i = 0; i < numpks; i++)
4588         {
4589                 Oid                     pktype = pktypoid[i];
4590                 Oid                     fktype = fktypoid[i];
4591                 Oid                     fktyped;
4592                 HeapTuple       cla_ht;
4593                 Form_pg_opclass cla_tup;
4594                 Oid                     amid;
4595                 Oid                     opfamily;
4596                 Oid                     opcintype;
4597                 Oid                     pfeqop;
4598                 Oid                     ppeqop;
4599                 Oid                     ffeqop;
4600                 int16           eqstrategy;
4601
4602                 /* We need several fields out of the pg_opclass entry */
4603                 cla_ht = SearchSysCache(CLAOID,
4604                                                                 ObjectIdGetDatum(opclasses[i]),
4605                                                                 0, 0, 0);
4606                 if (!HeapTupleIsValid(cla_ht))
4607                         elog(ERROR, "cache lookup failed for opclass %u", opclasses[i]);
4608                 cla_tup = (Form_pg_opclass) GETSTRUCT(cla_ht);
4609                 amid = cla_tup->opcmethod;
4610                 opfamily = cla_tup->opcfamily;
4611                 opcintype = cla_tup->opcintype;
4612                 ReleaseSysCache(cla_ht);
4613
4614                 /*
4615                  * Check it's a btree; currently this can never fail since no other
4616                  * index AMs support unique indexes.  If we ever did have other types
4617                  * of unique indexes, we'd need a way to determine which operator
4618                  * strategy number is equality.  (Is it reasonable to insist that
4619                  * every such index AM use btree's number for equality?)
4620                  */
4621                 if (amid != BTREE_AM_OID)
4622                         elog(ERROR, "only b-tree indexes are supported for foreign keys");
4623                 eqstrategy = BTEqualStrategyNumber;
4624
4625                 /*
4626                  * There had better be a primary equality operator for the index.
4627                  * We'll use it for PK = PK comparisons.
4628                  */
4629                 ppeqop = get_opfamily_member(opfamily, opcintype, opcintype,
4630                                                                          eqstrategy);
4631
4632                 if (!OidIsValid(ppeqop))
4633                         elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
4634                                  eqstrategy, opcintype, opcintype, opfamily);
4635
4636                 /*
4637                  * Are there equality operators that take exactly the FK type? Assume
4638                  * we should look through any domain here.
4639                  */
4640                 fktyped = getBaseType(fktype);
4641
4642                 pfeqop = get_opfamily_member(opfamily, opcintype, fktyped,
4643                                                                          eqstrategy);
4644                 if (OidIsValid(pfeqop))
4645                         ffeqop = get_opfamily_member(opfamily, fktyped, fktyped,
4646                                                                                  eqstrategy);
4647                 else
4648                         ffeqop = InvalidOid;    /* keep compiler quiet */
4649
4650                 if (!(OidIsValid(pfeqop) && OidIsValid(ffeqop)))
4651                 {
4652                         /*
4653                          * Otherwise, look for an implicit cast from the FK type to the
4654                          * opcintype, and if found, use the primary equality operator.
4655                          * This is a bit tricky because opcintype might be a polymorphic
4656                          * type such as ANYARRAY or ANYENUM; so what we have to test is
4657                          * whether the two actual column types can be concurrently cast to
4658                          * that type.  (Otherwise, we'd fail to reject combinations such
4659                          * as int[] and point[].)
4660                          */
4661                         Oid                     input_typeids[2];
4662                         Oid                     target_typeids[2];
4663
4664                         input_typeids[0] = pktype;
4665                         input_typeids[1] = fktype;
4666                         target_typeids[0] = opcintype;
4667                         target_typeids[1] = opcintype;
4668                         if (can_coerce_type(2, input_typeids, target_typeids,
4669                                                                 COERCION_IMPLICIT))
4670                                 pfeqop = ffeqop = ppeqop;
4671                 }
4672
4673                 if (!(OidIsValid(pfeqop) && OidIsValid(ffeqop)))
4674                         ereport(ERROR,
4675                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
4676                                          errmsg("foreign key constraint \"%s\" "
4677                                                         "cannot be implemented",
4678                                                         fkconstraint->constr_name),
4679                                          errdetail("Key columns \"%s\" and \"%s\" "
4680                                                            "are of incompatible types: %s and %s.",
4681                                                            strVal(list_nth(fkconstraint->fk_attrs, i)),
4682                                                            strVal(list_nth(fkconstraint->pk_attrs, i)),
4683                                                            format_type_be(fktype),
4684                                                            format_type_be(pktype))));
4685
4686                 pfeqoperators[i] = pfeqop;
4687                 ppeqoperators[i] = ppeqop;
4688                 ffeqoperators[i] = ffeqop;
4689         }
4690
4691         /*
4692          * Record the FK constraint in pg_constraint.
4693          */
4694         constrOid = CreateConstraintEntry(fkconstraint->constr_name,
4695                                                                           RelationGetNamespace(rel),
4696                                                                           CONSTRAINT_FOREIGN,
4697                                                                           fkconstraint->deferrable,
4698                                                                           fkconstraint->initdeferred,
4699                                                                           RelationGetRelid(rel),
4700                                                                           fkattnum,
4701                                                                           numfks,
4702                                                                           InvalidOid,           /* not a domain
4703                                                                                                                  * constraint */
4704                                                                           RelationGetRelid(pkrel),
4705                                                                           pkattnum,
4706                                                                           pfeqoperators,
4707                                                                           ppeqoperators,
4708                                                                           ffeqoperators,
4709                                                                           numpks,
4710                                                                           fkconstraint->fk_upd_action,
4711                                                                           fkconstraint->fk_del_action,
4712                                                                           fkconstraint->fk_matchtype,
4713                                                                           indexOid,
4714                                                                           NULL,         /* no check constraint */
4715                                                                           NULL,
4716                                                                           NULL,
4717                                                                           true, /* islocal */
4718                                                                           0); /* inhcount */
4719
4720         /*
4721          * Create the triggers that will enforce the constraint.
4722          */
4723         createForeignKeyTriggers(rel, fkconstraint, constrOid);
4724
4725         /*
4726          * Tell Phase 3 to check that the constraint is satisfied by existing rows
4727          * (we can skip this during table creation).
4728          */
4729         if (!fkconstraint->skip_validation)
4730         {
4731                 NewConstraint *newcon;
4732
4733                 newcon = (NewConstraint *) palloc0(sizeof(NewConstraint));
4734                 newcon->name = fkconstraint->constr_name;
4735                 newcon->contype = CONSTR_FOREIGN;
4736                 newcon->refrelid = RelationGetRelid(pkrel);
4737                 newcon->conid = constrOid;
4738                 newcon->qual = (Node *) fkconstraint;
4739
4740                 tab->constraints = lappend(tab->constraints, newcon);
4741         }
4742
4743         /*
4744          * Close pk table, but keep lock until we've committed.
4745          */
4746         heap_close(pkrel, NoLock);
4747 }
4748
4749
4750 /*
4751  * transformColumnNameList - transform list of column names
4752  *
4753  * Lookup each name and return its attnum and type OID
4754  */
4755 static int
4756 transformColumnNameList(Oid relId, List *colList,
4757                                                 int16 *attnums, Oid *atttypids)
4758 {
4759         ListCell   *l;
4760         int                     attnum;
4761
4762         attnum = 0;
4763         foreach(l, colList)
4764         {
4765                 char       *attname = strVal(lfirst(l));
4766                 HeapTuple       atttuple;
4767
4768                 atttuple = SearchSysCacheAttName(relId, attname);
4769                 if (!HeapTupleIsValid(atttuple))
4770                         ereport(ERROR,
4771                                         (errcode(ERRCODE_UNDEFINED_COLUMN),
4772                                          errmsg("column \"%s\" referenced in foreign key constraint does not exist",
4773                                                         attname)));
4774                 if (attnum >= INDEX_MAX_KEYS)
4775                         ereport(ERROR,
4776                                         (errcode(ERRCODE_TOO_MANY_COLUMNS),
4777                                          errmsg("cannot have more than %d keys in a foreign key",
4778                                                         INDEX_MAX_KEYS)));
4779                 attnums[attnum] = ((Form_pg_attribute) GETSTRUCT(atttuple))->attnum;
4780                 atttypids[attnum] = ((Form_pg_attribute) GETSTRUCT(atttuple))->atttypid;
4781                 ReleaseSysCache(atttuple);
4782                 attnum++;
4783         }
4784
4785         return attnum;
4786 }
4787
4788 /*
4789  * transformFkeyGetPrimaryKey -
4790  *
4791  *      Look up the names, attnums, and types of the primary key attributes
4792  *      for the pkrel.  Also return the index OID and index opclasses of the
4793  *      index supporting the primary key.
4794  *
4795  *      All parameters except pkrel are output parameters.      Also, the function
4796  *      return value is the number of attributes in the primary key.
4797  *
4798  *      Used when the column list in the REFERENCES specification is omitted.
4799  */
4800 static int
4801 transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
4802                                                    List **attnamelist,
4803                                                    int16 *attnums, Oid *atttypids,
4804                                                    Oid *opclasses)
4805 {
4806         List       *indexoidlist;
4807         ListCell   *indexoidscan;
4808         HeapTuple       indexTuple = NULL;
4809         Form_pg_index indexStruct = NULL;
4810         Datum           indclassDatum;
4811         bool            isnull;
4812         oidvector  *indclass;
4813         int                     i;
4814
4815         /*
4816          * Get the list of index OIDs for the table from the relcache, and look up
4817          * each one in the pg_index syscache until we find one marked primary key
4818          * (hopefully there isn't more than one such).
4819          */
4820         *indexOid = InvalidOid;
4821
4822         indexoidlist = RelationGetIndexList(pkrel);
4823
4824         foreach(indexoidscan, indexoidlist)
4825         {
4826                 Oid                     indexoid = lfirst_oid(indexoidscan);
4827
4828                 indexTuple = SearchSysCache(INDEXRELID,
4829                                                                         ObjectIdGetDatum(indexoid),
4830                                                                         0, 0, 0);
4831                 if (!HeapTupleIsValid(indexTuple))
4832                         elog(ERROR, "cache lookup failed for index %u", indexoid);
4833                 indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
4834                 if (indexStruct->indisprimary)
4835                 {
4836                         *indexOid = indexoid;
4837                         break;
4838                 }
4839                 ReleaseSysCache(indexTuple);
4840         }
4841
4842         list_free(indexoidlist);
4843
4844         /*
4845          * Check that we found it
4846          */
4847         if (!OidIsValid(*indexOid))
4848                 ereport(ERROR,
4849                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
4850                                  errmsg("there is no primary key for referenced table \"%s\"",
4851                                                 RelationGetRelationName(pkrel))));
4852
4853         /* Must get indclass the hard way */
4854         indclassDatum = SysCacheGetAttr(INDEXRELID, indexTuple,
4855                                                                         Anum_pg_index_indclass, &isnull);
4856         Assert(!isnull);
4857         indclass = (oidvector *) DatumGetPointer(indclassDatum);
4858
4859         /*
4860          * Now build the list of PK attributes from the indkey definition (we
4861          * assume a primary key cannot have expressional elements)
4862          */
4863         *attnamelist = NIL;
4864         for (i = 0; i < indexStruct->indnatts; i++)
4865         {
4866                 int                     pkattno = indexStruct->indkey.values[i];
4867
4868                 attnums[i] = pkattno;
4869                 atttypids[i] = attnumTypeId(pkrel, pkattno);
4870                 opclasses[i] = indclass->values[i];
4871                 *attnamelist = lappend(*attnamelist,
4872                            makeString(pstrdup(NameStr(*attnumAttName(pkrel, pkattno)))));
4873         }
4874
4875         ReleaseSysCache(indexTuple);
4876
4877         return i;
4878 }
4879
4880 /*
4881  * transformFkeyCheckAttrs -
4882  *
4883  *      Make sure that the attributes of a referenced table belong to a unique
4884  *      (or primary key) constraint.  Return the OID of the index supporting
4885  *      the constraint, as well as the opclasses associated with the index
4886  *      columns.
4887  */
4888 static Oid
4889 transformFkeyCheckAttrs(Relation pkrel,
4890                                                 int numattrs, int16 *attnums,
4891                                                 Oid *opclasses) /* output parameter */
4892 {
4893         Oid                     indexoid = InvalidOid;
4894         bool            found = false;
4895         List       *indexoidlist;
4896         ListCell   *indexoidscan;
4897
4898         /*
4899          * Get the list of index OIDs for the table from the relcache, and look up
4900          * each one in the pg_index syscache, and match unique indexes to the list
4901          * of attnums we are given.
4902          */
4903         indexoidlist = RelationGetIndexList(pkrel);
4904
4905         foreach(indexoidscan, indexoidlist)
4906         {
4907                 HeapTuple       indexTuple;
4908                 Form_pg_index indexStruct;
4909                 int                     i,
4910                                         j;
4911
4912                 indexoid = lfirst_oid(indexoidscan);
4913                 indexTuple = SearchSysCache(INDEXRELID,
4914                                                                         ObjectIdGetDatum(indexoid),
4915                                                                         0, 0, 0);
4916                 if (!HeapTupleIsValid(indexTuple))
4917                         elog(ERROR, "cache lookup failed for index %u", indexoid);
4918                 indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
4919
4920                 /*
4921                  * Must have the right number of columns; must be unique and not a
4922                  * partial index; forget it if there are any expressions, too
4923                  */
4924                 if (indexStruct->indnatts == numattrs &&
4925                         indexStruct->indisunique &&
4926                         heap_attisnull(indexTuple, Anum_pg_index_indpred) &&
4927                         heap_attisnull(indexTuple, Anum_pg_index_indexprs))
4928                 {
4929                         /* Must get indclass the hard way */
4930                         Datum           indclassDatum;
4931                         bool            isnull;
4932                         oidvector  *indclass;
4933
4934                         indclassDatum = SysCacheGetAttr(INDEXRELID, indexTuple,
4935                                                                                         Anum_pg_index_indclass, &isnull);
4936                         Assert(!isnull);
4937                         indclass = (oidvector *) DatumGetPointer(indclassDatum);
4938
4939                         /*
4940                          * The given attnum list may match the index columns in any order.
4941                          * Check that each list is a subset of the other.
4942                          */
4943                         for (i = 0; i < numattrs; i++)
4944                         {
4945                                 found = false;
4946                                 for (j = 0; j < numattrs; j++)
4947                                 {
4948                                         if (attnums[i] == indexStruct->indkey.values[j])
4949                                         {
4950                                                 found = true;
4951                                                 break;
4952                                         }
4953                                 }
4954                                 if (!found)
4955                                         break;
4956                         }
4957                         if (found)
4958                         {
4959                                 for (i = 0; i < numattrs; i++)
4960                                 {
4961                                         found = false;
4962                                         for (j = 0; j < numattrs; j++)
4963                                         {
4964                                                 if (attnums[j] == indexStruct->indkey.values[i])
4965                                                 {
4966                                                         opclasses[j] = indclass->values[i];
4967                                                         found = true;
4968                                                         break;
4969                                                 }
4970                                         }
4971                                         if (!found)
4972                                                 break;
4973                                 }
4974                         }
4975                 }
4976                 ReleaseSysCache(indexTuple);
4977                 if (found)
4978                         break;
4979         }
4980
4981         if (!found)
4982                 ereport(ERROR,
4983                                 (errcode(ERRCODE_INVALID_FOREIGN_KEY),
4984                                  errmsg("there is no unique constraint matching given keys for referenced table \"%s\"",
4985                                                 RelationGetRelationName(pkrel))));
4986
4987         list_free(indexoidlist);
4988
4989         return indexoid;
4990 }
4991
4992 /*
4993  * Scan the existing rows in a table to verify they meet a proposed FK
4994  * constraint.
4995  *
4996  * Caller must have opened and locked both relations.
4997  */
4998 static void
4999 validateForeignKeyConstraint(FkConstraint *fkconstraint,
5000                                                          Relation rel,
5001                                                          Relation pkrel,
5002                                                          Oid constraintOid)
5003 {
5004         HeapScanDesc scan;
5005         HeapTuple       tuple;
5006         Trigger         trig;
5007
5008         /*
5009          * Build a trigger call structure; we'll need it either way.
5010          */
5011         MemSet(&trig, 0, sizeof(trig));
5012         trig.tgoid = InvalidOid;
5013         trig.tgname = fkconstraint->constr_name;
5014         trig.tgenabled = TRIGGER_FIRES_ON_ORIGIN;
5015         trig.tgisconstraint = TRUE;
5016         trig.tgconstrrelid = RelationGetRelid(pkrel);
5017         trig.tgconstraint = constraintOid;
5018         trig.tgdeferrable = FALSE;
5019         trig.tginitdeferred = FALSE;
5020         /* we needn't fill in tgargs */
5021
5022         /*
5023          * See if we can do it with a single LEFT JOIN query.  A FALSE result
5024          * indicates we must proceed with the fire-the-trigger method.
5025          */
5026         if (RI_Initial_Check(&trig, rel, pkrel))
5027                 return;
5028
5029         /*
5030          * Scan through each tuple, calling RI_FKey_check_ins (insert trigger) as
5031          * if that tuple had just been inserted.  If any of those fail, it should
5032          * ereport(ERROR) and that's that.
5033          */
5034         scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
5035
5036         while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
5037         {
5038                 FunctionCallInfoData fcinfo;
5039                 TriggerData trigdata;
5040
5041                 /*
5042                  * Make a call to the trigger function
5043                  *
5044                  * No parameters are passed, but we do set a context
5045                  */
5046                 MemSet(&fcinfo, 0, sizeof(fcinfo));
5047
5048                 /*
5049                  * We assume RI_FKey_check_ins won't look at flinfo...
5050                  */
5051                 trigdata.type = T_TriggerData;
5052                 trigdata.tg_event = TRIGGER_EVENT_INSERT | TRIGGER_EVENT_ROW;
5053                 trigdata.tg_relation = rel;
5054                 trigdata.tg_trigtuple = tuple;
5055                 trigdata.tg_newtuple = NULL;
5056                 trigdata.tg_trigger = &trig;
5057                 trigdata.tg_trigtuplebuf = scan->rs_cbuf;
5058                 trigdata.tg_newtuplebuf = InvalidBuffer;
5059
5060                 fcinfo.context = (Node *) &trigdata;
5061
5062                 RI_FKey_check_ins(&fcinfo);
5063         }
5064
5065         heap_endscan(scan);
5066 }
5067
5068 static void
5069 CreateFKCheckTrigger(RangeVar *myRel, FkConstraint *fkconstraint,
5070                                          Oid constraintOid, bool on_insert)
5071 {
5072         CreateTrigStmt *fk_trigger;
5073
5074         fk_trigger = makeNode(CreateTrigStmt);
5075         fk_trigger->trigname = fkconstraint->constr_name;
5076         fk_trigger->relation = myRel;
5077         fk_trigger->before = false;
5078         fk_trigger->row = true;
5079
5080         /* Either ON INSERT or ON UPDATE */
5081         if (on_insert)
5082         {
5083                 fk_trigger->funcname = SystemFuncName("RI_FKey_check_ins");
5084                 fk_trigger->actions[0] = 'i';
5085         }
5086         else
5087         {
5088                 fk_trigger->funcname = SystemFuncName("RI_FKey_check_upd");
5089                 fk_trigger->actions[0] = 'u';
5090         }
5091         fk_trigger->actions[1] = '\0';
5092
5093         fk_trigger->isconstraint = true;
5094         fk_trigger->deferrable = fkconstraint->deferrable;
5095         fk_trigger->initdeferred = fkconstraint->initdeferred;
5096         fk_trigger->constrrel = fkconstraint->pktable;
5097         fk_trigger->args = NIL;
5098
5099         (void) CreateTrigger(fk_trigger, constraintOid);
5100
5101         /* Make changes-so-far visible */
5102         CommandCounterIncrement();
5103 }
5104
5105 /*
5106  * Create the triggers that implement an FK constraint.
5107  */
5108 static void
5109 createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
5110                                                  Oid constraintOid)
5111 {
5112         RangeVar   *myRel;
5113         CreateTrigStmt *fk_trigger;
5114
5115         /*
5116          * Reconstruct a RangeVar for my relation (not passed in, unfortunately).
5117          */
5118         myRel = makeRangeVar(get_namespace_name(RelationGetNamespace(rel)),
5119                                                  pstrdup(RelationGetRelationName(rel)),
5120                                                  -1);
5121
5122         /* Make changes-so-far visible */
5123         CommandCounterIncrement();
5124
5125         /*
5126          * Build and execute a CREATE CONSTRAINT TRIGGER statement for the CHECK
5127          * action for both INSERTs and UPDATEs on the referencing table.
5128          */
5129         CreateFKCheckTrigger(myRel, fkconstraint, constraintOid, true);
5130         CreateFKCheckTrigger(myRel, fkconstraint, constraintOid, false);
5131
5132         /*
5133          * Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON
5134          * DELETE action on the referenced table.
5135          */
5136         fk_trigger = makeNode(CreateTrigStmt);
5137         fk_trigger->trigname = fkconstraint->constr_name;
5138         fk_trigger->relation = fkconstraint->pktable;
5139         fk_trigger->before = false;
5140         fk_trigger->row = true;
5141         fk_trigger->actions[0] = 'd';
5142         fk_trigger->actions[1] = '\0';
5143
5144         fk_trigger->isconstraint = true;
5145         fk_trigger->constrrel = myRel;
5146         switch (fkconstraint->fk_del_action)
5147         {
5148                 case FKCONSTR_ACTION_NOACTION:
5149                         fk_trigger->deferrable = fkconstraint->deferrable;
5150                         fk_trigger->initdeferred = fkconstraint->initdeferred;
5151                         fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_del");
5152                         break;
5153                 case FKCONSTR_ACTION_RESTRICT:
5154                         fk_trigger->deferrable = false;
5155                         fk_trigger->initdeferred = false;
5156                         fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_del");
5157                         break;
5158                 case FKCONSTR_ACTION_CASCADE:
5159                         fk_trigger->deferrable = false;
5160                         fk_trigger->initdeferred = false;
5161                         fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_del");
5162                         break;
5163                 case FKCONSTR_ACTION_SETNULL:
5164                         fk_trigger->deferrable = false;
5165                         fk_trigger->initdeferred = false;
5166                         fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_del");
5167                         break;
5168                 case FKCONSTR_ACTION_SETDEFAULT:
5169                         fk_trigger->deferrable = false;
5170                         fk_trigger->initdeferred = false;
5171                         fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_del");
5172                         break;
5173                 default:
5174                         elog(ERROR, "unrecognized FK action type: %d",
5175                                  (int) fkconstraint->fk_del_action);
5176                         break;
5177         }
5178         fk_trigger->args = NIL;
5179
5180         (void) CreateTrigger(fk_trigger, constraintOid);
5181
5182         /* Make changes-so-far visible */
5183         CommandCounterIncrement();
5184
5185         /*
5186          * Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON
5187          * UPDATE action on the referenced table.
5188          */
5189         fk_trigger = makeNode(CreateTrigStmt);
5190         fk_trigger->trigname = fkconstraint->constr_name;
5191         fk_trigger->relation = fkconstraint->pktable;
5192         fk_trigger->before = false;
5193         fk_trigger->row = true;
5194         fk_trigger->actions[0] = 'u';
5195         fk_trigger->actions[1] = '\0';
5196         fk_trigger->isconstraint = true;
5197         fk_trigger->constrrel = myRel;
5198         switch (fkconstraint->fk_upd_action)
5199         {
5200                 case FKCONSTR_ACTION_NOACTION:
5201                         fk_trigger->deferrable = fkconstraint->deferrable;
5202                         fk_trigger->initdeferred = fkconstraint->initdeferred;
5203                         fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_upd");
5204                         break;
5205                 case FKCONSTR_ACTION_RESTRICT:
5206                         fk_trigger->deferrable = false;
5207                         fk_trigger->initdeferred = false;
5208                         fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_upd");
5209                         break;
5210                 case FKCONSTR_ACTION_CASCADE:
5211                         fk_trigger->deferrable = false;
5212                         fk_trigger->initdeferred = false;
5213                         fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_upd");
5214                         break;
5215                 case FKCONSTR_ACTION_SETNULL:
5216                         fk_trigger->deferrable = false;
5217                         fk_trigger->initdeferred = false;
5218                         fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_upd");
5219                         break;
5220                 case FKCONSTR_ACTION_SETDEFAULT:
5221                         fk_trigger->deferrable = false;
5222                         fk_trigger->initdeferred = false;
5223                         fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_upd");
5224                         break;
5225                 default:
5226                         elog(ERROR, "unrecognized FK action type: %d",
5227                                  (int) fkconstraint->fk_upd_action);
5228                         break;
5229         }
5230         fk_trigger->args = NIL;
5231
5232         (void) CreateTrigger(fk_trigger, constraintOid);
5233 }
5234
5235 /*
5236  * ALTER TABLE DROP CONSTRAINT
5237  *
5238  * Like DROP COLUMN, we can't use the normal ALTER TABLE recursion mechanism.
5239  */
5240 static void
5241 ATExecDropConstraint(Relation rel, const char *constrName,
5242                                          DropBehavior behavior,
5243                                          bool recurse, bool recursing)
5244 {
5245         List       *children;
5246         ListCell   *child;
5247         Relation        conrel;
5248         Form_pg_constraint con;
5249         SysScanDesc scan;
5250         ScanKeyData key;
5251         HeapTuple       tuple;
5252         bool            found = false;
5253         bool            is_check_constraint = false;
5254
5255         /* At top level, permission check was done in ATPrepCmd, else do it */
5256         if (recursing)
5257                 ATSimplePermissions(rel, false);
5258
5259         conrel = heap_open(ConstraintRelationId, RowExclusiveLock);
5260
5261         /*
5262          * Find and drop the target constraint
5263          */
5264         ScanKeyInit(&key,
5265                                 Anum_pg_constraint_conrelid,
5266                                 BTEqualStrategyNumber, F_OIDEQ,
5267                                 ObjectIdGetDatum(RelationGetRelid(rel)));
5268         scan = systable_beginscan(conrel, ConstraintRelidIndexId,
5269                                                           true, SnapshotNow, 1, &key);
5270
5271         while (HeapTupleIsValid(tuple = systable_getnext(scan)))
5272         {
5273                 ObjectAddress conobj;
5274
5275                 con = (Form_pg_constraint) GETSTRUCT(tuple);
5276
5277                 if (strcmp(NameStr(con->conname), constrName) != 0)
5278                         continue;
5279
5280                 /* Don't drop inherited constraints */
5281                 if (con->coninhcount > 0 && !recursing)
5282                         ereport(ERROR,
5283                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
5284                                  errmsg("cannot drop inherited constraint \"%s\" of relation \"%s\"",
5285                                                 constrName, RelationGetRelationName(rel))));
5286
5287                 /* Right now only CHECK constraints can be inherited */
5288                 if (con->contype == CONSTRAINT_CHECK)
5289                         is_check_constraint = true;
5290
5291                 /*
5292                  * Perform the actual constraint deletion
5293                  */
5294                 conobj.classId = ConstraintRelationId;
5295                 conobj.objectId = HeapTupleGetOid(tuple);
5296                 conobj.objectSubId = 0;
5297
5298                 performDeletion(&conobj, behavior);
5299
5300                 found = true;
5301         }
5302
5303         systable_endscan(scan);
5304
5305         if (!found)
5306                 ereport(ERROR,
5307                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
5308                                  errmsg("constraint \"%s\" of relation \"%s\" does not exist",
5309                                                 constrName, RelationGetRelationName(rel))));
5310
5311         /*
5312          * Propagate to children as appropriate.  Unlike most other ALTER
5313          * routines, we have to do this one level of recursion at a time; we can't
5314          * use find_all_inheritors to do it in one pass.
5315          */
5316         if (is_check_constraint)
5317                 children = find_inheritance_children(RelationGetRelid(rel));
5318         else
5319                 children = NIL;
5320
5321         foreach(child, children)
5322         {
5323                 Oid                     childrelid = lfirst_oid(child);
5324                 Relation        childrel;
5325
5326                 childrel = heap_open(childrelid, AccessExclusiveLock);
5327                 CheckTableNotInUse(childrel, "ALTER TABLE");
5328
5329                 ScanKeyInit(&key,
5330                                         Anum_pg_constraint_conrelid,
5331                                         BTEqualStrategyNumber, F_OIDEQ,
5332                                         ObjectIdGetDatum(childrelid));
5333                 scan = systable_beginscan(conrel, ConstraintRelidIndexId,
5334                                                                   true, SnapshotNow, 1, &key);
5335
5336                 found = false;
5337
5338                 while (HeapTupleIsValid(tuple = systable_getnext(scan)))
5339                 {
5340                         HeapTuple copy_tuple;
5341
5342                         con = (Form_pg_constraint) GETSTRUCT(tuple);
5343
5344                         /* Right now only CHECK constraints can be inherited */
5345                         if (con->contype != CONSTRAINT_CHECK)
5346                                 continue;
5347
5348                         if (strcmp(NameStr(con->conname), constrName) != 0)
5349                                 continue;
5350
5351                         found = true;
5352
5353                         if (con->coninhcount <= 0)              /* shouldn't happen */
5354                                 elog(ERROR, "relation %u has non-inherited constraint \"%s\"",
5355                                          childrelid, constrName);
5356
5357                         copy_tuple = heap_copytuple(tuple);
5358                         con = (Form_pg_constraint) GETSTRUCT(copy_tuple);
5359
5360                         if (recurse)
5361                         {
5362                                 /*
5363                                  * If the child constraint has other definition sources,
5364                                  * just decrement its inheritance count; if not, recurse
5365                                  * to delete it.
5366                                  */
5367                                 if (con->coninhcount == 1 && !con->conislocal)
5368                                 {
5369                                         /* Time to delete this child constraint, too */
5370                                         ATExecDropConstraint(childrel, constrName, behavior,
5371                                                                                  true, true);
5372                                 }
5373                                 else
5374                                 {
5375                                         /* Child constraint must survive my deletion */
5376                                         con->coninhcount--;
5377                                         simple_heap_update(conrel, &copy_tuple->t_self, copy_tuple);
5378                                         CatalogUpdateIndexes(conrel, copy_tuple);
5379
5380                                         /* Make update visible */
5381                                         CommandCounterIncrement();
5382                                 }
5383                         }
5384                         else
5385                         {
5386                                 /*
5387                                  * If we were told to drop ONLY in this table (no
5388                                  * recursion), we need to mark the inheritors' constraints
5389                                  * as locally defined rather than inherited.
5390                                  */
5391                                 con->coninhcount--;
5392                                 con->conislocal = true;
5393
5394                                 simple_heap_update(conrel, &copy_tuple->t_self, copy_tuple);
5395                                 CatalogUpdateIndexes(conrel, copy_tuple);
5396
5397                                 /* Make update visible */
5398                                 CommandCounterIncrement();
5399                         }
5400
5401                         heap_freetuple(copy_tuple);
5402                 }
5403
5404                 systable_endscan(scan);
5405
5406                 if (!found)
5407                         ereport(ERROR,
5408                                         (errcode(ERRCODE_UNDEFINED_OBJECT),
5409                                          errmsg("constraint \"%s\" of relation \"%s\" does not exist",
5410                                                         constrName,
5411                                                         RelationGetRelationName(childrel))));
5412
5413                 heap_close(childrel, NoLock);
5414         }
5415
5416         heap_close(conrel, RowExclusiveLock);
5417 }
5418
5419 /*
5420  * ALTER COLUMN TYPE
5421  */
5422 static void
5423 ATPrepAlterColumnType(List **wqueue,
5424                                           AlteredTableInfo *tab, Relation rel,
5425                                           bool recurse, bool recursing,
5426                                           AlterTableCmd *cmd)
5427 {
5428         char       *colName = cmd->name;
5429         TypeName   *typename = (TypeName *) cmd->def;
5430         HeapTuple       tuple;
5431         Form_pg_attribute attTup;
5432         AttrNumber      attnum;
5433         Oid                     targettype;
5434         int32           targettypmod;
5435         Node       *transform;
5436         NewColumnValue *newval;
5437         ParseState *pstate = make_parsestate(NULL);
5438
5439         /* lookup the attribute so we can check inheritance status */
5440         tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
5441         if (!HeapTupleIsValid(tuple))
5442                 ereport(ERROR,
5443                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
5444                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
5445                                                 colName, RelationGetRelationName(rel))));
5446         attTup = (Form_pg_attribute) GETSTRUCT(tuple);
5447         attnum = attTup->attnum;
5448
5449         /* Can't alter a system attribute */
5450         if (attnum <= 0)
5451                 ereport(ERROR,
5452                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
5453                                  errmsg("cannot alter system column \"%s\"",
5454                                                 colName)));
5455
5456         /* Don't alter inherited columns */
5457         if (attTup->attinhcount > 0 && !recursing)
5458                 ereport(ERROR,
5459                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
5460                                  errmsg("cannot alter inherited column \"%s\"",
5461                                                 colName)));
5462
5463         /* Look up the target type */
5464         targettype = typenameTypeId(NULL, typename, &targettypmod);
5465
5466         /* make sure datatype is legal for a column */
5467         CheckAttributeType(colName, targettype);
5468
5469         /*
5470          * Set up an expression to transform the old data value to the new type.
5471          * If a USING option was given, transform and use that expression, else
5472          * just take the old value and try to coerce it.  We do this first so that
5473          * type incompatibility can be detected before we waste effort, and
5474          * because we need the expression to be parsed against the original table
5475          * rowtype.
5476          */
5477         if (cmd->transform)
5478         {
5479                 RangeTblEntry *rte;
5480
5481                 /* Expression must be able to access vars of old table */
5482                 rte = addRangeTableEntryForRelation(pstate,
5483                                                                                         rel,
5484                                                                                         NULL,
5485                                                                                         false,
5486                                                                                         true);
5487                 addRTEtoQuery(pstate, rte, false, true, true);
5488
5489                 transform = transformExpr(pstate, cmd->transform);
5490
5491                 /* It can't return a set */
5492                 if (expression_returns_set(transform))
5493                         ereport(ERROR,
5494                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
5495                                          errmsg("transform expression must not return a set")));
5496
5497                 /* No subplans or aggregates, either... */
5498                 if (pstate->p_hasSubLinks)
5499                         ereport(ERROR,
5500                                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
5501                                          errmsg("cannot use subquery in transform expression")));
5502                 if (pstate->p_hasAggs)
5503                         ereport(ERROR,
5504                                         (errcode(ERRCODE_GROUPING_ERROR),
5505                         errmsg("cannot use aggregate function in transform expression")));
5506         }
5507         else
5508         {
5509                 transform = (Node *) makeVar(1, attnum,
5510                                                                          attTup->atttypid, attTup->atttypmod,
5511                                                                          0);
5512         }
5513
5514         transform = coerce_to_target_type(pstate,
5515                                                                           transform, exprType(transform),
5516                                                                           targettype, targettypmod,
5517                                                                           COERCION_ASSIGNMENT,
5518                                                                           COERCE_IMPLICIT_CAST,
5519                                                                           -1);
5520         if (transform == NULL)
5521                 ereport(ERROR,
5522                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
5523                                  errmsg("column \"%s\" cannot be cast to type %s",
5524                                                 colName, format_type_be(targettype))));
5525
5526         /*
5527          * Add a work queue item to make ATRewriteTable update the column
5528          * contents.
5529          */
5530         newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
5531         newval->attnum = attnum;
5532         newval->expr = (Expr *) transform;
5533
5534         tab->newvals = lappend(tab->newvals, newval);
5535
5536         ReleaseSysCache(tuple);
5537
5538         /*
5539          * The recursion case is handled by ATSimpleRecursion.  However, if we are
5540          * told not to recurse, there had better not be any child tables; else the
5541          * alter would put them out of step.
5542          */
5543         if (recurse)
5544                 ATSimpleRecursion(wqueue, rel, cmd, recurse);
5545         else if (!recursing &&
5546                          find_inheritance_children(RelationGetRelid(rel)) != NIL)
5547                 ereport(ERROR,
5548                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
5549                                  errmsg("type of inherited column \"%s\" must be changed in child tables too",
5550                                                 colName)));
5551 }
5552
5553 static void
5554 ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
5555                                           const char *colName, TypeName *typename)
5556 {
5557         HeapTuple       heapTup;
5558         Form_pg_attribute attTup;
5559         AttrNumber      attnum;
5560         HeapTuple       typeTuple;
5561         Form_pg_type tform;
5562         Oid                     targettype;
5563         int32           targettypmod;
5564         Node       *defaultexpr;
5565         Relation        attrelation;
5566         Relation        depRel;
5567         ScanKeyData key[3];
5568         SysScanDesc scan;
5569         HeapTuple       depTup;
5570
5571         attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
5572
5573         /* Look up the target column */
5574         heapTup = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
5575         if (!HeapTupleIsValid(heapTup))         /* shouldn't happen */
5576                 ereport(ERROR,
5577                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
5578                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
5579                                                 colName, RelationGetRelationName(rel))));
5580         attTup = (Form_pg_attribute) GETSTRUCT(heapTup);
5581         attnum = attTup->attnum;
5582
5583         /* Check for multiple ALTER TYPE on same column --- can't cope */
5584         if (attTup->atttypid != tab->oldDesc->attrs[attnum - 1]->atttypid ||
5585                 attTup->atttypmod != tab->oldDesc->attrs[attnum - 1]->atttypmod)
5586                 ereport(ERROR,
5587                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
5588                                  errmsg("cannot alter type of column \"%s\" twice",
5589                                                 colName)));
5590
5591         /* Look up the target type (should not fail, since prep found it) */
5592         typeTuple = typenameType(NULL, typename, &targettypmod);
5593         tform = (Form_pg_type) GETSTRUCT(typeTuple);
5594         targettype = HeapTupleGetOid(typeTuple);
5595
5596         /*
5597          * If there is a default expression for the column, get it and ensure we
5598          * can coerce it to the new datatype.  (We must do this before changing
5599          * the column type, because build_column_default itself will try to
5600          * coerce, and will not issue the error message we want if it fails.)
5601          *
5602          * We remove any implicit coercion steps at the top level of the old
5603          * default expression; this has been agreed to satisfy the principle of
5604          * least surprise.      (The conversion to the new column type should act like
5605          * it started from what the user sees as the stored expression, and the
5606          * implicit coercions aren't going to be shown.)
5607          */
5608         if (attTup->atthasdef)
5609         {
5610                 defaultexpr = build_column_default(rel, attnum);
5611                 Assert(defaultexpr);
5612                 defaultexpr = strip_implicit_coercions(defaultexpr);
5613                 defaultexpr = coerce_to_target_type(NULL,               /* no UNKNOWN params */
5614                                                                                   defaultexpr, exprType(defaultexpr),
5615                                                                                         targettype, targettypmod,
5616                                                                                         COERCION_ASSIGNMENT,
5617                                                                                         COERCE_IMPLICIT_CAST,
5618                                                                                         -1);
5619                 if (defaultexpr == NULL)
5620                         ereport(ERROR,
5621                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
5622                         errmsg("default for column \"%s\" cannot be cast to type %s",
5623                                    colName, format_type_be(targettype))));
5624         }
5625         else
5626                 defaultexpr = NULL;
5627
5628         /*
5629          * Find everything that depends on the column (constraints, indexes, etc),
5630          * and record enough information to let us recreate the objects.
5631          *
5632          * The actual recreation does not happen here, but only after we have
5633          * performed all the individual ALTER TYPE operations.  We have to save
5634          * the info before executing ALTER TYPE, though, else the deparser will
5635          * get confused.
5636          *
5637          * There could be multiple entries for the same object, so we must check
5638          * to ensure we process each one only once.  Note: we assume that an index
5639          * that implements a constraint will not show a direct dependency on the
5640          * column.
5641          */
5642         depRel = heap_open(DependRelationId, RowExclusiveLock);
5643
5644         ScanKeyInit(&key[0],
5645                                 Anum_pg_depend_refclassid,
5646                                 BTEqualStrategyNumber, F_OIDEQ,
5647                                 ObjectIdGetDatum(RelationRelationId));
5648         ScanKeyInit(&key[1],
5649                                 Anum_pg_depend_refobjid,
5650                                 BTEqualStrategyNumber, F_OIDEQ,
5651                                 ObjectIdGetDatum(RelationGetRelid(rel)));
5652         ScanKeyInit(&key[2],
5653                                 Anum_pg_depend_refobjsubid,
5654                                 BTEqualStrategyNumber, F_INT4EQ,
5655                                 Int32GetDatum((int32) attnum));
5656
5657         scan = systable_beginscan(depRel, DependReferenceIndexId, true,
5658                                                           SnapshotNow, 3, key);
5659
5660         while (HeapTupleIsValid(depTup = systable_getnext(scan)))
5661         {
5662                 Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(depTup);
5663                 ObjectAddress foundObject;
5664
5665                 /* We don't expect any PIN dependencies on columns */
5666                 if (foundDep->deptype == DEPENDENCY_PIN)
5667                         elog(ERROR, "cannot alter type of a pinned column");
5668
5669                 foundObject.classId = foundDep->classid;
5670                 foundObject.objectId = foundDep->objid;
5671                 foundObject.objectSubId = foundDep->objsubid;
5672
5673                 switch (getObjectClass(&foundObject))
5674                 {
5675                         case OCLASS_CLASS:
5676                                 {
5677                                         char            relKind = get_rel_relkind(foundObject.objectId);
5678
5679                                         if (relKind == RELKIND_INDEX)
5680                                         {
5681                                                 Assert(foundObject.objectSubId == 0);
5682                                                 if (!list_member_oid(tab->changedIndexOids, foundObject.objectId))
5683                                                 {
5684                                                         tab->changedIndexOids = lappend_oid(tab->changedIndexOids,
5685                                                                                                            foundObject.objectId);
5686                                                         tab->changedIndexDefs = lappend(tab->changedIndexDefs,
5687                                                            pg_get_indexdef_string(foundObject.objectId));
5688                                                 }
5689                                         }
5690                                         else if (relKind == RELKIND_SEQUENCE)
5691                                         {
5692                                                 /*
5693                                                  * This must be a SERIAL column's sequence.  We need
5694                                                  * not do anything to it.
5695                                                  */
5696                                                 Assert(foundObject.objectSubId == 0);
5697                                         }
5698                                         else
5699                                         {
5700                                                 /* Not expecting any other direct dependencies... */
5701                                                 elog(ERROR, "unexpected object depending on column: %s",
5702                                                          getObjectDescription(&foundObject));
5703                                         }
5704                                         break;
5705                                 }
5706
5707                         case OCLASS_CONSTRAINT:
5708                                 Assert(foundObject.objectSubId == 0);
5709                                 if (!list_member_oid(tab->changedConstraintOids,
5710                                                                          foundObject.objectId))
5711                                 {
5712                                         char       *defstring = pg_get_constraintdef_string(foundObject.objectId);
5713
5714                                         /*
5715                                          * Put NORMAL dependencies at the front of the list and
5716                                          * AUTO dependencies at the back.  This makes sure that
5717                                          * foreign-key constraints depending on this column will
5718                                          * be dropped before unique or primary-key constraints of
5719                                          * the column; which we must have because the FK
5720                                          * constraints depend on the indexes belonging to the
5721                                          * unique constraints.
5722                                          */
5723                                         if (foundDep->deptype == DEPENDENCY_NORMAL)
5724                                         {
5725                                                 tab->changedConstraintOids =
5726                                                         lcons_oid(foundObject.objectId,
5727                                                                           tab->changedConstraintOids);
5728                                                 tab->changedConstraintDefs =
5729                                                         lcons(defstring,
5730                                                                   tab->changedConstraintDefs);
5731                                         }
5732                                         else
5733                                         {
5734                                                 tab->changedConstraintOids =
5735                                                         lappend_oid(tab->changedConstraintOids,
5736                                                                                 foundObject.objectId);
5737                                                 tab->changedConstraintDefs =
5738                                                         lappend(tab->changedConstraintDefs,
5739                                                                         defstring);
5740                                         }
5741                                 }
5742                                 break;
5743
5744                         case OCLASS_REWRITE:
5745                                 /* XXX someday see if we can cope with revising views */
5746                                 ereport(ERROR,
5747                                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
5748                                                  errmsg("cannot alter type of a column used by a view or rule"),
5749                                                  errdetail("%s depends on column \"%s\"",
5750                                                                    getObjectDescription(&foundObject),
5751                                                                    colName)));
5752                                 break;
5753
5754                         case OCLASS_DEFAULT:
5755
5756                                 /*
5757                                  * Ignore the column's default expression, since we will fix
5758                                  * it below.
5759                                  */
5760                                 Assert(defaultexpr);
5761                                 break;
5762
5763                         case OCLASS_PROC:
5764                         case OCLASS_TYPE:
5765                         case OCLASS_CAST:
5766                         case OCLASS_CONVERSION:
5767                         case OCLASS_LANGUAGE:
5768                         case OCLASS_OPERATOR:
5769                         case OCLASS_OPCLASS:
5770                         case OCLASS_OPFAMILY:
5771                         case OCLASS_TRIGGER:
5772                         case OCLASS_SCHEMA:
5773                         case OCLASS_TSPARSER:
5774                         case OCLASS_TSDICT:
5775                         case OCLASS_TSTEMPLATE:
5776                         case OCLASS_TSCONFIG:
5777
5778                                 /*
5779                                  * We don't expect any of these sorts of objects to depend on
5780                                  * a column.
5781                                  */
5782                                 elog(ERROR, "unexpected object depending on column: %s",
5783                                          getObjectDescription(&foundObject));
5784                                 break;
5785
5786                         default:
5787                                 elog(ERROR, "unrecognized object class: %u",
5788                                          foundObject.classId);
5789                 }
5790         }
5791
5792         systable_endscan(scan);
5793
5794         /*
5795          * Now scan for dependencies of this column on other things.  The only
5796          * thing we should find is the dependency on the column datatype, which we
5797          * want to remove.
5798          */
5799         ScanKeyInit(&key[0],
5800                                 Anum_pg_depend_classid,
5801                                 BTEqualStrategyNumber, F_OIDEQ,
5802                                 ObjectIdGetDatum(RelationRelationId));
5803         ScanKeyInit(&key[1],
5804                                 Anum_pg_depend_objid,
5805                                 BTEqualStrategyNumber, F_OIDEQ,
5806                                 ObjectIdGetDatum(RelationGetRelid(rel)));
5807         ScanKeyInit(&key[2],
5808                                 Anum_pg_depend_objsubid,
5809                                 BTEqualStrategyNumber, F_INT4EQ,
5810                                 Int32GetDatum((int32) attnum));
5811
5812         scan = systable_beginscan(depRel, DependDependerIndexId, true,
5813                                                           SnapshotNow, 3, key);
5814
5815         while (HeapTupleIsValid(depTup = systable_getnext(scan)))
5816         {
5817                 Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(depTup);
5818
5819                 if (foundDep->deptype != DEPENDENCY_NORMAL)
5820                         elog(ERROR, "found unexpected dependency type '%c'",
5821                                  foundDep->deptype);
5822                 if (foundDep->refclassid != TypeRelationId ||
5823                         foundDep->refobjid != attTup->atttypid)
5824                         elog(ERROR, "found unexpected dependency for column");
5825
5826                 simple_heap_delete(depRel, &depTup->t_self);
5827         }
5828
5829         systable_endscan(scan);
5830
5831         heap_close(depRel, RowExclusiveLock);
5832
5833         /*
5834          * Here we go --- change the recorded column type.      (Note heapTup is a
5835          * copy of the syscache entry, so okay to scribble on.)
5836          */
5837         attTup->atttypid = targettype;
5838         attTup->atttypmod = targettypmod;
5839         attTup->attndims = list_length(typename->arrayBounds);
5840         attTup->attlen = tform->typlen;
5841         attTup->attbyval = tform->typbyval;
5842         attTup->attalign = tform->typalign;
5843         attTup->attstorage = tform->typstorage;
5844
5845         ReleaseSysCache(typeTuple);
5846
5847         simple_heap_update(attrelation, &heapTup->t_self, heapTup);
5848
5849         /* keep system catalog indexes current */
5850         CatalogUpdateIndexes(attrelation, heapTup);
5851
5852         heap_close(attrelation, RowExclusiveLock);
5853
5854         /* Install dependency on new datatype */
5855         add_column_datatype_dependency(RelationGetRelid(rel), attnum, targettype);
5856
5857         /*
5858          * Drop any pg_statistic entry for the column, since it's now wrong type
5859          */
5860         RemoveStatistics(RelationGetRelid(rel), attnum);
5861
5862         /*
5863          * Update the default, if present, by brute force --- remove and re-add
5864          * the default.  Probably unsafe to take shortcuts, since the new version
5865          * may well have additional dependencies.  (It's okay to do this now,
5866          * rather than after other ALTER TYPE commands, since the default won't
5867          * depend on other column types.)
5868          */
5869         if (defaultexpr)
5870         {
5871                 /* Must make new row visible since it will be updated again */
5872                 CommandCounterIncrement();
5873
5874                 /*
5875                  * We use RESTRICT here for safety, but at present we do not expect
5876                  * anything to depend on the default.
5877                  */
5878                 RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, true);
5879
5880                 StoreAttrDefault(rel, attnum, defaultexpr);
5881         }
5882
5883         /* Cleanup */
5884         heap_freetuple(heapTup);
5885 }
5886
5887 /*
5888  * Cleanup after we've finished all the ALTER TYPE operations for a
5889  * particular relation.  We have to drop and recreate all the indexes
5890  * and constraints that depend on the altered columns.
5891  */
5892 static void
5893 ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab)
5894 {
5895         ObjectAddress obj;
5896         ListCell   *l;
5897
5898         /*
5899          * Re-parse the index and constraint definitions, and attach them to the
5900          * appropriate work queue entries.      We do this before dropping because in
5901          * the case of a FOREIGN KEY constraint, we might not yet have exclusive
5902          * lock on the table the constraint is attached to, and we need to get
5903          * that before dropping.  It's safe because the parser won't actually look
5904          * at the catalogs to detect the existing entry.
5905          */
5906         foreach(l, tab->changedIndexDefs)
5907                 ATPostAlterTypeParse((char *) lfirst(l), wqueue);
5908         foreach(l, tab->changedConstraintDefs)
5909                 ATPostAlterTypeParse((char *) lfirst(l), wqueue);
5910
5911         /*
5912          * Now we can drop the existing constraints and indexes --- constraints
5913          * first, since some of them might depend on the indexes.  In fact, we
5914          * have to delete FOREIGN KEY constraints before UNIQUE constraints, but
5915          * we already ordered the constraint list to ensure that would happen. It
5916          * should be okay to use DROP_RESTRICT here, since nothing else should be
5917          * depending on these objects.
5918          */
5919         foreach(l, tab->changedConstraintOids)
5920         {
5921                 obj.classId = ConstraintRelationId;
5922                 obj.objectId = lfirst_oid(l);
5923                 obj.objectSubId = 0;
5924                 performDeletion(&obj, DROP_RESTRICT);
5925         }
5926
5927         foreach(l, tab->changedIndexOids)
5928         {
5929                 obj.classId = RelationRelationId;
5930                 obj.objectId = lfirst_oid(l);
5931                 obj.objectSubId = 0;
5932                 performDeletion(&obj, DROP_RESTRICT);
5933         }
5934
5935         /*
5936          * The objects will get recreated during subsequent passes over the work
5937          * queue.
5938          */
5939 }
5940
5941 static void
5942 ATPostAlterTypeParse(char *cmd, List **wqueue)
5943 {
5944         List       *raw_parsetree_list;
5945         List       *querytree_list;
5946         ListCell   *list_item;
5947
5948         /*
5949          * We expect that we will get only ALTER TABLE and CREATE INDEX
5950          * statements. Hence, there is no need to pass them through
5951          * parse_analyze() or the rewriter, but instead we need to pass them
5952          * through parse_utilcmd.c to make them ready for execution.
5953          */
5954         raw_parsetree_list = raw_parser(cmd);
5955         querytree_list = NIL;
5956         foreach(list_item, raw_parsetree_list)
5957         {
5958                 Node       *stmt = (Node *) lfirst(list_item);
5959
5960                 if (IsA(stmt, IndexStmt))
5961                         querytree_list = lappend(querytree_list,
5962                                                                          transformIndexStmt((IndexStmt *) stmt,
5963                                                                                                                 cmd));
5964                 else if (IsA(stmt, AlterTableStmt))
5965                         querytree_list = list_concat(querytree_list,
5966                                                          transformAlterTableStmt((AlterTableStmt *) stmt,
5967                                                                                                          cmd));
5968                 else
5969                         querytree_list = lappend(querytree_list, stmt);
5970         }
5971
5972         /*
5973          * Attach each generated command to the proper place in the work queue.
5974          * Note this could result in creation of entirely new work-queue entries.
5975          */
5976         foreach(list_item, querytree_list)
5977         {
5978                 Node       *stm = (Node *) lfirst(list_item);
5979                 Relation        rel;
5980                 AlteredTableInfo *tab;
5981
5982                 switch (nodeTag(stm))
5983                 {
5984                         case T_IndexStmt:
5985                                 {
5986                                         IndexStmt  *stmt = (IndexStmt *) stm;
5987                                         AlterTableCmd *newcmd;
5988
5989                                         rel = relation_openrv(stmt->relation, AccessExclusiveLock);
5990                                         tab = ATGetQueueEntry(wqueue, rel);
5991                                         newcmd = makeNode(AlterTableCmd);
5992                                         newcmd->subtype = AT_ReAddIndex;
5993                                         newcmd->def = (Node *) stmt;
5994                                         tab->subcmds[AT_PASS_OLD_INDEX] =
5995                                                 lappend(tab->subcmds[AT_PASS_OLD_INDEX], newcmd);
5996                                         relation_close(rel, NoLock);
5997                                         break;
5998                                 }
5999                         case T_AlterTableStmt:
6000                                 {
6001                                         AlterTableStmt *stmt = (AlterTableStmt *) stm;
6002                                         ListCell   *lcmd;
6003
6004                                         rel = relation_openrv(stmt->relation, AccessExclusiveLock);
6005                                         tab = ATGetQueueEntry(wqueue, rel);
6006                                         foreach(lcmd, stmt->cmds)
6007                                         {
6008                                                 AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd);
6009
6010                                                 switch (cmd->subtype)
6011                                                 {
6012                                                         case AT_AddIndex:
6013                                                                 cmd->subtype = AT_ReAddIndex;
6014                                                                 tab->subcmds[AT_PASS_OLD_INDEX] =
6015                                                                         lappend(tab->subcmds[AT_PASS_OLD_INDEX], cmd);
6016                                                                 break;
6017                                                         case AT_AddConstraint:
6018                                                                 tab->subcmds[AT_PASS_OLD_CONSTR] =
6019                                                                         lappend(tab->subcmds[AT_PASS_OLD_CONSTR], cmd);
6020                                                                 break;
6021                                                         default:
6022                                                                 elog(ERROR, "unexpected statement type: %d",
6023                                                                          (int) cmd->subtype);
6024                                                 }
6025                                         }
6026                                         relation_close(rel, NoLock);
6027                                         break;
6028                                 }
6029                         default:
6030                                 elog(ERROR, "unexpected statement type: %d",
6031                                          (int) nodeTag(stm));
6032                 }
6033         }
6034 }
6035
6036
6037 /*
6038  * ALTER TABLE OWNER
6039  *
6040  * recursing is true if we are recursing from a table to its indexes,
6041  * sequences, or toast table.  We don't allow the ownership of those things to
6042  * be changed separately from the parent table.  Also, we can skip permission
6043  * checks (this is necessary not just an optimization, else we'd fail to
6044  * handle toast tables properly).
6045  *
6046  * recursing is also true if ALTER TYPE OWNER is calling us to fix up a
6047  * free-standing composite type.
6048  */
6049 void
6050 ATExecChangeOwner(Oid relationOid, Oid newOwnerId, bool recursing)
6051 {
6052         Relation        target_rel;
6053         Relation        class_rel;
6054         HeapTuple       tuple;
6055         Form_pg_class tuple_class;
6056
6057         /*
6058          * Get exclusive lock till end of transaction on the target table. Use
6059          * relation_open so that we can work on indexes and sequences.
6060          */
6061         target_rel = relation_open(relationOid, AccessExclusiveLock);
6062
6063         /* Get its pg_class tuple, too */
6064         class_rel = heap_open(RelationRelationId, RowExclusiveLock);
6065
6066         tuple = SearchSysCache(RELOID,
6067                                                    ObjectIdGetDatum(relationOid),
6068                                                    0, 0, 0);
6069         if (!HeapTupleIsValid(tuple))
6070                 elog(ERROR, "cache lookup failed for relation %u", relationOid);
6071         tuple_class = (Form_pg_class) GETSTRUCT(tuple);
6072
6073         /* Can we change the ownership of this tuple? */
6074         switch (tuple_class->relkind)
6075         {
6076                 case RELKIND_RELATION:
6077                 case RELKIND_VIEW:
6078                         /* ok to change owner */
6079                         break;
6080                 case RELKIND_INDEX:
6081                         if (!recursing)
6082                         {
6083                                 /*
6084                                  * Because ALTER INDEX OWNER used to be allowed, and in fact
6085                                  * is generated by old versions of pg_dump, we give a warning
6086                                  * and do nothing rather than erroring out.  Also, to avoid
6087                                  * unnecessary chatter while restoring those old dumps, say
6088                                  * nothing at all if the command would be a no-op anyway.
6089                                  */
6090                                 if (tuple_class->relowner != newOwnerId)
6091                                         ereport(WARNING,
6092                                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
6093                                                          errmsg("cannot change owner of index \"%s\"",
6094                                                                         NameStr(tuple_class->relname)),
6095                                                          errhint("Change the ownership of the index's table, instead.")));
6096                                 /* quick hack to exit via the no-op path */
6097                                 newOwnerId = tuple_class->relowner;
6098                         }
6099                         break;
6100                 case RELKIND_SEQUENCE:
6101                         if (!recursing &&
6102                                 tuple_class->relowner != newOwnerId)
6103                         {
6104                                 /* if it's an owned sequence, disallow changing it by itself */
6105                                 Oid                     tableId;
6106                                 int32           colId;
6107
6108                                 if (sequenceIsOwned(relationOid, &tableId, &colId))
6109                                         ereport(ERROR,
6110                                                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
6111                                                          errmsg("cannot change owner of sequence \"%s\"",
6112                                                                         NameStr(tuple_class->relname)),
6113                                           errdetail("Sequence \"%s\" is linked to table \"%s\".",
6114                                                                 NameStr(tuple_class->relname),
6115                                                                 get_rel_name(tableId))));
6116                         }
6117                         break;
6118                 case RELKIND_COMPOSITE_TYPE:
6119                         if (recursing)
6120                                 break;
6121                         ereport(ERROR,
6122                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
6123                                          errmsg("\"%s\" is a composite type",
6124                                                         NameStr(tuple_class->relname)),
6125                                          errhint("Use ALTER TYPE instead.")));
6126                         break;
6127                 case RELKIND_TOASTVALUE:
6128                         if (recursing)
6129                                 break;
6130                         /* FALL THRU */
6131                 default:
6132                         ereport(ERROR,
6133                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
6134                                          errmsg("\"%s\" is not a table, view, or sequence",
6135                                                         NameStr(tuple_class->relname))));
6136         }
6137
6138         /*
6139          * If the new owner is the same as the existing owner, consider the
6140          * command to have succeeded.  This is for dump restoration purposes.
6141          */
6142         if (tuple_class->relowner != newOwnerId)
6143         {
6144                 Datum           repl_val[Natts_pg_class];
6145                 bool            repl_null[Natts_pg_class];
6146                 bool            repl_repl[Natts_pg_class];
6147                 Acl                *newAcl;
6148                 Datum           aclDatum;
6149                 bool            isNull;
6150                 HeapTuple       newtuple;
6151
6152                 /* skip permission checks when recursing to index or toast table */
6153                 if (!recursing)
6154                 {
6155                         /* Superusers can always do it */
6156                         if (!superuser())
6157                         {
6158                                 Oid                     namespaceOid = tuple_class->relnamespace;
6159                                 AclResult       aclresult;
6160
6161                                 /* Otherwise, must be owner of the existing object */
6162                                 if (!pg_class_ownercheck(relationOid, GetUserId()))
6163                                         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
6164                                                                    RelationGetRelationName(target_rel));
6165
6166                                 /* Must be able to become new owner */
6167                                 check_is_member_of_role(GetUserId(), newOwnerId);
6168
6169                                 /* New owner must have CREATE privilege on namespace */
6170                                 aclresult = pg_namespace_aclcheck(namespaceOid, newOwnerId,
6171                                                                                                   ACL_CREATE);
6172                                 if (aclresult != ACLCHECK_OK)
6173                                         aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
6174                                                                    get_namespace_name(namespaceOid));
6175                         }
6176                 }
6177
6178                 memset(repl_null, false, sizeof(repl_null));
6179                 memset(repl_repl, false, sizeof(repl_repl));
6180
6181                 repl_repl[Anum_pg_class_relowner - 1] = true;
6182                 repl_val[Anum_pg_class_relowner - 1] = ObjectIdGetDatum(newOwnerId);
6183
6184                 /*
6185                  * Determine the modified ACL for the new owner.  This is only
6186                  * necessary when the ACL is non-null.
6187                  */
6188                 aclDatum = SysCacheGetAttr(RELOID, tuple,
6189                                                                    Anum_pg_class_relacl,
6190                                                                    &isNull);
6191                 if (!isNull)
6192                 {
6193                         newAcl = aclnewowner(DatumGetAclP(aclDatum),
6194                                                                  tuple_class->relowner, newOwnerId);
6195                         repl_repl[Anum_pg_class_relacl - 1] = true;
6196                         repl_val[Anum_pg_class_relacl - 1] = PointerGetDatum(newAcl);
6197                 }
6198
6199                 newtuple = heap_modify_tuple(tuple, RelationGetDescr(class_rel), repl_val, repl_null, repl_repl);
6200
6201                 simple_heap_update(class_rel, &newtuple->t_self, newtuple);
6202                 CatalogUpdateIndexes(class_rel, newtuple);
6203
6204                 heap_freetuple(newtuple);
6205
6206                 /*
6207                  * Update owner dependency reference, if any.  A composite type has
6208                  * none, because it's tracked for the pg_type entry instead of here;
6209                  * indexes and TOAST tables don't have their own entries either.
6210                  */
6211                 if (tuple_class->relkind != RELKIND_COMPOSITE_TYPE &&
6212                         tuple_class->relkind != RELKIND_INDEX &&
6213                         tuple_class->relkind != RELKIND_TOASTVALUE)
6214                         changeDependencyOnOwner(RelationRelationId, relationOid,
6215                                                                         newOwnerId);
6216
6217                 /*
6218                  * Also change the ownership of the table's rowtype, if it has one
6219                  */
6220                 if (tuple_class->relkind != RELKIND_INDEX)
6221                         AlterTypeOwnerInternal(tuple_class->reltype, newOwnerId,
6222                                                          tuple_class->relkind == RELKIND_COMPOSITE_TYPE);
6223
6224                 /*
6225                  * If we are operating on a table, also change the ownership of any
6226                  * indexes and sequences that belong to the table, as well as the
6227                  * table's toast table (if it has one)
6228                  */
6229                 if (tuple_class->relkind == RELKIND_RELATION ||
6230                         tuple_class->relkind == RELKIND_TOASTVALUE)
6231                 {
6232                         List       *index_oid_list;
6233                         ListCell   *i;
6234
6235                         /* Find all the indexes belonging to this relation */
6236                         index_oid_list = RelationGetIndexList(target_rel);
6237
6238                         /* For each index, recursively change its ownership */
6239                         foreach(i, index_oid_list)
6240                                 ATExecChangeOwner(lfirst_oid(i), newOwnerId, true);
6241
6242                         list_free(index_oid_list);
6243                 }
6244
6245                 if (tuple_class->relkind == RELKIND_RELATION)
6246                 {
6247                         /* If it has a toast table, recurse to change its ownership */
6248                         if (tuple_class->reltoastrelid != InvalidOid)
6249                                 ATExecChangeOwner(tuple_class->reltoastrelid, newOwnerId,
6250                                                                   true);
6251
6252                         /* If it has dependent sequences, recurse to change them too */
6253                         change_owner_recurse_to_sequences(relationOid, newOwnerId);
6254                 }
6255         }
6256
6257         ReleaseSysCache(tuple);
6258         heap_close(class_rel, RowExclusiveLock);
6259         relation_close(target_rel, NoLock);
6260 }
6261
6262 /*
6263  * change_owner_recurse_to_sequences
6264  *
6265  * Helper function for ATExecChangeOwner.  Examines pg_depend searching
6266  * for sequences that are dependent on serial columns, and changes their
6267  * ownership.
6268  */
6269 static void
6270 change_owner_recurse_to_sequences(Oid relationOid, Oid newOwnerId)
6271 {
6272         Relation        depRel;
6273         SysScanDesc scan;
6274         ScanKeyData key[2];
6275         HeapTuple       tup;
6276
6277         /*
6278          * SERIAL sequences are those having an auto dependency on one of the
6279          * table's columns (we don't care *which* column, exactly).
6280          */
6281         depRel = heap_open(DependRelationId, AccessShareLock);
6282
6283         ScanKeyInit(&key[0],
6284                                 Anum_pg_depend_refclassid,
6285                                 BTEqualStrategyNumber, F_OIDEQ,
6286                                 ObjectIdGetDatum(RelationRelationId));
6287         ScanKeyInit(&key[1],
6288                                 Anum_pg_depend_refobjid,
6289                                 BTEqualStrategyNumber, F_OIDEQ,
6290                                 ObjectIdGetDatum(relationOid));
6291         /* we leave refobjsubid unspecified */
6292
6293         scan = systable_beginscan(depRel, DependReferenceIndexId, true,
6294                                                           SnapshotNow, 2, key);
6295
6296         while (HeapTupleIsValid(tup = systable_getnext(scan)))
6297         {
6298                 Form_pg_depend depForm = (Form_pg_depend) GETSTRUCT(tup);
6299                 Relation        seqRel;
6300
6301                 /* skip dependencies other than auto dependencies on columns */
6302                 if (depForm->refobjsubid == 0 ||
6303                         depForm->classid != RelationRelationId ||
6304                         depForm->objsubid != 0 ||
6305                         depForm->deptype != DEPENDENCY_AUTO)
6306                         continue;
6307
6308                 /* Use relation_open just in case it's an index */
6309                 seqRel = relation_open(depForm->objid, AccessExclusiveLock);
6310
6311                 /* skip non-sequence relations */
6312                 if (RelationGetForm(seqRel)->relkind != RELKIND_SEQUENCE)
6313                 {
6314                         /* No need to keep the lock */
6315                         relation_close(seqRel, AccessExclusiveLock);
6316                         continue;
6317                 }
6318
6319                 /* We don't need to close the sequence while we alter it. */
6320                 ATExecChangeOwner(depForm->objid, newOwnerId, true);
6321
6322                 /* Now we can close it.  Keep the lock till end of transaction. */
6323                 relation_close(seqRel, NoLock);
6324         }
6325
6326         systable_endscan(scan);
6327
6328         relation_close(depRel, AccessShareLock);
6329 }
6330
6331 /*
6332  * ALTER TABLE CLUSTER ON
6333  *
6334  * The only thing we have to do is to change the indisclustered bits.
6335  */
6336 static void
6337 ATExecClusterOn(Relation rel, const char *indexName)
6338 {
6339         Oid                     indexOid;
6340
6341         indexOid = get_relname_relid(indexName, rel->rd_rel->relnamespace);
6342
6343         if (!OidIsValid(indexOid))
6344                 ereport(ERROR,
6345                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
6346                                  errmsg("index \"%s\" for table \"%s\" does not exist",
6347                                                 indexName, RelationGetRelationName(rel))));
6348
6349         /* Check index is valid to cluster on */
6350         check_index_is_clusterable(rel, indexOid, false);
6351
6352         /* And do the work */
6353         mark_index_clustered(rel, indexOid);
6354 }
6355
6356 /*
6357  * ALTER TABLE SET WITHOUT CLUSTER
6358  *
6359  * We have to find any indexes on the table that have indisclustered bit
6360  * set and turn it off.
6361  */
6362 static void
6363 ATExecDropCluster(Relation rel)
6364 {
6365         mark_index_clustered(rel, InvalidOid);
6366 }
6367
6368 /*
6369  * ALTER TABLE SET TABLESPACE
6370  */
6371 static void
6372 ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel, char *tablespacename)
6373 {
6374         Oid                     tablespaceId;
6375         AclResult       aclresult;
6376
6377         /* Check that the tablespace exists */
6378         tablespaceId = get_tablespace_oid(tablespacename);
6379         if (!OidIsValid(tablespaceId))
6380                 ereport(ERROR,
6381                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
6382                                  errmsg("tablespace \"%s\" does not exist", tablespacename)));
6383
6384         /* Check its permissions */
6385         aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(), ACL_CREATE);
6386         if (aclresult != ACLCHECK_OK)
6387                 aclcheck_error(aclresult, ACL_KIND_TABLESPACE, tablespacename);
6388
6389         /* Save info for Phase 3 to do the real work */
6390         if (OidIsValid(tab->newTableSpace))
6391                 ereport(ERROR,
6392                                 (errcode(ERRCODE_SYNTAX_ERROR),
6393                                  errmsg("cannot have multiple SET TABLESPACE subcommands")));
6394         tab->newTableSpace = tablespaceId;
6395 }
6396
6397 /*
6398  * ALTER TABLE/INDEX SET (...) or RESET (...)
6399  */
6400 static void
6401 ATExecSetRelOptions(Relation rel, List *defList, bool isReset)
6402 {
6403         Oid                     relid;
6404         Relation        pgclass;
6405         HeapTuple       tuple;
6406         HeapTuple       newtuple;
6407         Datum           datum;
6408         bool            isnull;
6409         Datum           newOptions;
6410         Datum           repl_val[Natts_pg_class];
6411         bool            repl_null[Natts_pg_class];
6412         bool            repl_repl[Natts_pg_class];
6413
6414         if (defList == NIL)
6415                 return;                                 /* nothing to do */
6416
6417         pgclass = heap_open(RelationRelationId, RowExclusiveLock);
6418
6419         /* Get the old reloptions */
6420         relid = RelationGetRelid(rel);
6421         tuple = SearchSysCache(RELOID,
6422                                                    ObjectIdGetDatum(relid),
6423                                                    0, 0, 0);
6424         if (!HeapTupleIsValid(tuple))
6425                 elog(ERROR, "cache lookup failed for relation %u", relid);
6426
6427         datum = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_reloptions, &isnull);
6428
6429         /* Generate new proposed reloptions (text array) */
6430         newOptions = transformRelOptions(isnull ? (Datum) 0 : datum,
6431                                                                          defList, false, isReset);
6432
6433         /* Validate */
6434         switch (rel->rd_rel->relkind)
6435         {
6436                 case RELKIND_RELATION:
6437                 case RELKIND_TOASTVALUE:
6438                         (void) heap_reloptions(rel->rd_rel->relkind, newOptions, true);
6439                         break;
6440                 case RELKIND_INDEX:
6441                         (void) index_reloptions(rel->rd_am->amoptions, newOptions, true);
6442                         break;
6443                 default:
6444                         ereport(ERROR,
6445                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
6446                                          errmsg("\"%s\" is not a table, index, or TOAST table",
6447                                                         RelationGetRelationName(rel))));
6448                         break;
6449         }
6450
6451         /*
6452          * All we need do here is update the pg_class row; the new options will be
6453          * propagated into relcaches during post-commit cache inval.
6454          */
6455         memset(repl_val, 0, sizeof(repl_val));
6456         memset(repl_null, false, sizeof(repl_null));
6457         memset(repl_repl, false, sizeof(repl_repl));
6458
6459         if (newOptions != (Datum) 0)
6460                 repl_val[Anum_pg_class_reloptions - 1] = newOptions;
6461         else
6462                 repl_null[Anum_pg_class_reloptions - 1] = true;
6463
6464         repl_repl[Anum_pg_class_reloptions - 1] = true;
6465
6466         newtuple = heap_modify_tuple(tuple, RelationGetDescr(pgclass),
6467                                                                 repl_val, repl_null, repl_repl);
6468
6469         simple_heap_update(pgclass, &newtuple->t_self, newtuple);
6470
6471         CatalogUpdateIndexes(pgclass, newtuple);
6472
6473         heap_freetuple(newtuple);
6474
6475         ReleaseSysCache(tuple);
6476
6477         heap_close(pgclass, RowExclusiveLock);
6478 }
6479
6480 /*
6481  * Execute ALTER TABLE SET TABLESPACE for cases where there is no tuple
6482  * rewriting to be done, so we just want to copy the data as fast as possible.
6483  */
6484 static void
6485 ATExecSetTableSpace(Oid tableOid, Oid newTableSpace)
6486 {
6487         Relation        rel;
6488         Oid                     oldTableSpace;
6489         Oid                     reltoastrelid;
6490         Oid                     reltoastidxid;
6491         Oid                     newrelfilenode;
6492         RelFileNode newrnode;
6493         SMgrRelation dstrel;
6494         Relation        pg_class;
6495         HeapTuple       tuple;
6496         Form_pg_class rd_rel;
6497         ForkNumber      forkNum;
6498
6499         /*
6500          * Need lock here in case we are recursing to toast table or index
6501          */
6502         rel = relation_open(tableOid, AccessExclusiveLock);
6503
6504         /*
6505          * We can never allow moving of shared or nailed-in-cache relations,
6506          * because we can't support changing their reltablespace values.
6507          */
6508         if (rel->rd_rel->relisshared || rel->rd_isnailed)
6509                 ereport(ERROR,
6510                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
6511                                  errmsg("cannot move system relation \"%s\"",
6512                                                 RelationGetRelationName(rel))));
6513
6514         /* Can't move a non-shared relation into pg_global */
6515         if (newTableSpace == GLOBALTABLESPACE_OID)
6516                 ereport(ERROR,
6517                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
6518                                  errmsg("only shared relations can be placed in pg_global tablespace")));
6519
6520         /*
6521          * Don't allow moving temp tables of other backends ... their local buffer
6522          * manager is not going to cope.
6523          */
6524         if (isOtherTempNamespace(RelationGetNamespace(rel)))
6525                 ereport(ERROR,
6526                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
6527                                  errmsg("cannot move temporary tables of other sessions")));
6528
6529         /*
6530          * No work if no change in tablespace.
6531          */
6532         oldTableSpace = rel->rd_rel->reltablespace;
6533         if (newTableSpace == oldTableSpace ||
6534                 (newTableSpace == MyDatabaseTableSpace && oldTableSpace == 0))
6535         {
6536                 relation_close(rel, NoLock);
6537                 return;
6538         }
6539
6540         reltoastrelid = rel->rd_rel->reltoastrelid;
6541         reltoastidxid = rel->rd_rel->reltoastidxid;
6542
6543         /* Get a modifiable copy of the relation's pg_class row */
6544         pg_class = heap_open(RelationRelationId, RowExclusiveLock);
6545
6546         tuple = SearchSysCacheCopy(RELOID,
6547                                                            ObjectIdGetDatum(tableOid),
6548                                                            0, 0, 0);
6549         if (!HeapTupleIsValid(tuple))
6550                 elog(ERROR, "cache lookup failed for relation %u", tableOid);
6551         rd_rel = (Form_pg_class) GETSTRUCT(tuple);
6552
6553         /*
6554          * Since we copy the file directly without looking at the shared buffers,
6555          * we'd better first flush out any pages of the source relation that are
6556          * in shared buffers.  We assume no new changes will be made while we are
6557          * holding exclusive lock on the rel.
6558          */
6559         FlushRelationBuffers(rel);
6560
6561         /*
6562          * Relfilenodes are not unique across tablespaces, so we need to allocate
6563          * a new one in the new tablespace.
6564          */
6565         newrelfilenode = GetNewRelFileNode(newTableSpace,
6566                                                                            rel->rd_rel->relisshared,
6567                                                                            NULL);
6568
6569         /* Open old and new relation */
6570         newrnode = rel->rd_node;
6571         newrnode.relNode = newrelfilenode;
6572         newrnode.spcNode = newTableSpace;
6573         dstrel = smgropen(newrnode);
6574
6575         RelationOpenSmgr(rel);
6576
6577         /*
6578          * Create and copy all forks of the relation, and schedule unlinking
6579          * of old physical files.
6580          *
6581          * NOTE: any conflict in relfilenode value will be caught in
6582          *               smgrcreate() below.
6583          */
6584         for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
6585         {
6586                 if (smgrexists(rel->rd_smgr, forkNum))
6587                 {
6588                         smgrcreate(dstrel, forkNum, rel->rd_istemp, false);
6589                         copy_relation_data(rel->rd_smgr, dstrel, forkNum, rel->rd_istemp);
6590
6591                         smgrscheduleunlink(rel->rd_smgr, forkNum, rel->rd_istemp);
6592                 }
6593         }
6594
6595         /* Close old and new relation */
6596         smgrclose(dstrel);
6597         RelationCloseSmgr(rel);
6598
6599         /* update the pg_class row */
6600         rd_rel->reltablespace = (newTableSpace == MyDatabaseTableSpace) ? InvalidOid : newTableSpace;
6601         rd_rel->relfilenode = newrelfilenode;
6602         simple_heap_update(pg_class, &tuple->t_self, tuple);
6603         CatalogUpdateIndexes(pg_class, tuple);
6604
6605         heap_freetuple(tuple);
6606
6607         heap_close(pg_class, RowExclusiveLock);
6608
6609         relation_close(rel, NoLock);
6610
6611         /* Make sure the reltablespace change is visible */
6612         CommandCounterIncrement();
6613
6614         /* Move associated toast relation and/or index, too */
6615         if (OidIsValid(reltoastrelid))
6616                 ATExecSetTableSpace(reltoastrelid, newTableSpace);
6617         if (OidIsValid(reltoastidxid))
6618                 ATExecSetTableSpace(reltoastidxid, newTableSpace);
6619 }
6620
6621 /*
6622  * Copy data, block by block
6623  */
6624 static void
6625 copy_relation_data(SMgrRelation src, SMgrRelation dst,
6626                                    ForkNumber forkNum, bool istemp)
6627 {
6628         bool            use_wal;
6629         BlockNumber nblocks;
6630         BlockNumber blkno;
6631         char            buf[BLCKSZ];
6632         Page            page = (Page) buf;
6633
6634         /*
6635          * We need to log the copied data in WAL iff WAL archiving is enabled AND
6636          * it's not a temp rel.
6637          */
6638         use_wal = XLogArchivingActive() && !istemp;
6639
6640         nblocks = smgrnblocks(src, forkNum);
6641
6642         for (blkno = 0; blkno < nblocks; blkno++)
6643         {
6644                 smgrread(src, forkNum, blkno, buf);
6645
6646                 /* XLOG stuff */
6647                 if (use_wal)
6648                         log_newpage(&dst->smgr_rnode, forkNum, blkno, page);
6649
6650                 /*
6651                  * Now write the page.  We say isTemp = true even if it's not a temp
6652                  * rel, because there's no need for smgr to schedule an fsync for this
6653                  * write; we'll do it ourselves below.
6654                  */
6655                 smgrextend(dst, forkNum, blkno, buf, true);
6656         }
6657
6658         /*
6659          * If the rel isn't temp, we must fsync it down to disk before it's safe
6660          * to commit the transaction.  (For a temp rel we don't care since the rel
6661          * will be uninteresting after a crash anyway.)
6662          *
6663          * It's obvious that we must do this when not WAL-logging the copy. It's
6664          * less obvious that we have to do it even if we did WAL-log the copied
6665          * pages. The reason is that since we're copying outside shared buffers, a
6666          * CHECKPOINT occurring during the copy has no way to flush the previously
6667          * written data to disk (indeed it won't know the new rel even exists).  A
6668          * crash later on would replay WAL from the checkpoint, therefore it
6669          * wouldn't replay our earlier WAL entries. If we do not fsync those pages
6670          * here, they might still not be on disk when the crash occurs.
6671          */
6672         if (!istemp)
6673                 smgrimmedsync(dst, forkNum);
6674 }
6675
6676 /*
6677  * ALTER TABLE ENABLE/DISABLE TRIGGER
6678  *
6679  * We just pass this off to trigger.c.
6680  */
6681 static void
6682 ATExecEnableDisableTrigger(Relation rel, char *trigname,
6683                                                    char fires_when, bool skip_system)
6684 {
6685         EnableDisableTrigger(rel, trigname, fires_when, skip_system);
6686 }
6687
6688 /*
6689  * ALTER TABLE ENABLE/DISABLE RULE
6690  *
6691  * We just pass this off to rewriteDefine.c.
6692  */
6693 static void
6694 ATExecEnableDisableRule(Relation rel, char *trigname,
6695                                                 char fires_when)
6696 {
6697         EnableDisableRule(rel, trigname, fires_when);
6698 }
6699
6700 /*
6701  * ALTER TABLE INHERIT
6702  *
6703  * Add a parent to the child's parents. This verifies that all the columns and
6704  * check constraints of the parent appear in the child and that they have the
6705  * same data types and expressions.
6706  */
6707 static void
6708 ATExecAddInherit(Relation child_rel, RangeVar *parent)
6709 {
6710         Relation        parent_rel,
6711                                 catalogRelation;
6712         SysScanDesc scan;
6713         ScanKeyData key;
6714         HeapTuple       inheritsTuple;
6715         int32           inhseqno;
6716         List       *children;
6717
6718         /*
6719          * AccessShareLock on the parent is what's obtained during normal CREATE
6720          * TABLE ... INHERITS ..., so should be enough here.
6721          */
6722         parent_rel = heap_openrv(parent, AccessShareLock);
6723
6724         /*
6725          * Must be owner of both parent and child -- child was checked by
6726          * ATSimplePermissions call in ATPrepCmd
6727          */
6728         ATSimplePermissions(parent_rel, false);
6729
6730         /* Permanent rels cannot inherit from temporary ones */
6731         if (!isTempNamespace(RelationGetNamespace(child_rel)) &&
6732                 isTempNamespace(RelationGetNamespace(parent_rel)))
6733                 ereport(ERROR,
6734                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
6735                                  errmsg("cannot inherit from temporary relation \"%s\"",
6736                                                 RelationGetRelationName(parent_rel))));
6737
6738         /*
6739          * Check for duplicates in the list of parents, and determine the highest
6740          * inhseqno already present; we'll use the next one for the new parent.
6741          * (Note: get RowExclusiveLock because we will write pg_inherits below.)
6742          *
6743          * Note: we do not reject the case where the child already inherits from
6744          * the parent indirectly; CREATE TABLE doesn't reject comparable cases.
6745          */
6746         catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock);
6747         ScanKeyInit(&key,
6748                                 Anum_pg_inherits_inhrelid,
6749                                 BTEqualStrategyNumber, F_OIDEQ,
6750                                 ObjectIdGetDatum(RelationGetRelid(child_rel)));
6751         scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId,
6752                                                           true, SnapshotNow, 1, &key);
6753
6754         /* inhseqno sequences start at 1 */
6755         inhseqno = 0;
6756         while (HeapTupleIsValid(inheritsTuple = systable_getnext(scan)))
6757         {
6758                 Form_pg_inherits inh = (Form_pg_inherits) GETSTRUCT(inheritsTuple);
6759
6760                 if (inh->inhparent == RelationGetRelid(parent_rel))
6761                         ereport(ERROR,
6762                                         (errcode(ERRCODE_DUPLICATE_TABLE),
6763                          errmsg("relation \"%s\" would be inherited from more than once",
6764                                         RelationGetRelationName(parent_rel))));
6765                 if (inh->inhseqno > inhseqno)
6766                         inhseqno = inh->inhseqno;
6767         }
6768         systable_endscan(scan);
6769
6770         /*
6771          * Prevent circularity by seeing if proposed parent inherits from child.
6772          * (In particular, this disallows making a rel inherit from itself.)
6773          *
6774          * This is not completely bulletproof because of race conditions: in
6775          * multi-level inheritance trees, someone else could concurrently be
6776          * making another inheritance link that closes the loop but does not join
6777          * either of the rels we have locked.  Preventing that seems to require
6778          * exclusive locks on the entire inheritance tree, which is a cure worse
6779          * than the disease.  find_all_inheritors() will cope with circularity
6780          * anyway, so don't sweat it too much.
6781          */
6782         children = find_all_inheritors(RelationGetRelid(child_rel));
6783
6784         if (list_member_oid(children, RelationGetRelid(parent_rel)))
6785                 ereport(ERROR,
6786                                 (errcode(ERRCODE_DUPLICATE_TABLE),
6787                                  errmsg("circular inheritance not allowed"),
6788                                  errdetail("\"%s\" is already a child of \"%s\".",
6789                                                    parent->relname,
6790                                                    RelationGetRelationName(child_rel))));
6791
6792         /* If parent has OIDs then child must have OIDs */
6793         if (parent_rel->rd_rel->relhasoids && !child_rel->rd_rel->relhasoids)
6794                 ereport(ERROR,
6795                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
6796                                  errmsg("table \"%s\" without OIDs cannot inherit from table \"%s\" with OIDs",
6797                                                 RelationGetRelationName(child_rel),
6798                                                 RelationGetRelationName(parent_rel))));
6799
6800         /* Match up the columns and bump attinhcount as needed */
6801         MergeAttributesIntoExisting(child_rel, parent_rel);
6802
6803         /* Match up the constraints and bump coninhcount as needed */
6804         MergeConstraintsIntoExisting(child_rel, parent_rel);
6805
6806         /*
6807          * OK, it looks valid.  Make the catalog entries that show inheritance.
6808          */
6809         StoreCatalogInheritance1(RelationGetRelid(child_rel),
6810                                                          RelationGetRelid(parent_rel),
6811                                                          inhseqno + 1,
6812                                                          catalogRelation);
6813
6814         /* Now we're done with pg_inherits */
6815         heap_close(catalogRelation, RowExclusiveLock);
6816
6817         /* keep our lock on the parent relation until commit */
6818         heap_close(parent_rel, NoLock);
6819 }
6820
6821 /*
6822  * Obtain the source-text form of the constraint expression for a check
6823  * constraint, given its pg_constraint tuple
6824  */
6825 static char *
6826 decompile_conbin(HeapTuple contup, TupleDesc tupdesc)
6827 {
6828         Form_pg_constraint con;
6829         bool            isnull;
6830         Datum           attr;
6831         Datum           expr;
6832
6833         con = (Form_pg_constraint) GETSTRUCT(contup);
6834         attr = heap_getattr(contup, Anum_pg_constraint_conbin, tupdesc, &isnull);
6835         if (isnull)
6836                 elog(ERROR, "null conbin for constraint %u", HeapTupleGetOid(contup));
6837
6838         expr = DirectFunctionCall2(pg_get_expr, attr,
6839                                                            ObjectIdGetDatum(con->conrelid));
6840         return TextDatumGetCString(expr);
6841 }
6842
6843 /*
6844  * Determine whether two check constraints are functionally equivalent
6845  *
6846  * The test we apply is to see whether they reverse-compile to the same
6847  * source string.  This insulates us from issues like whether attributes
6848  * have the same physical column numbers in parent and child relations.
6849  */
6850 static bool
6851 constraints_equivalent(HeapTuple a, HeapTuple b, TupleDesc tupleDesc)
6852 {
6853         Form_pg_constraint acon = (Form_pg_constraint) GETSTRUCT(a);
6854         Form_pg_constraint bcon = (Form_pg_constraint) GETSTRUCT(b);
6855
6856         if (acon->condeferrable != bcon->condeferrable ||
6857                 acon->condeferred != bcon->condeferred ||
6858                 strcmp(decompile_conbin(a, tupleDesc),
6859                            decompile_conbin(b, tupleDesc)) != 0)
6860                 return false;
6861         else
6862                 return true;
6863 }
6864
6865 /*
6866  * Check columns in child table match up with columns in parent, and increment
6867  * their attinhcount.
6868  *
6869  * Called by ATExecAddInherit
6870  *
6871  * Currently all parent columns must be found in child. Missing columns are an
6872  * error.  One day we might consider creating new columns like CREATE TABLE
6873  * does.  However, that is widely unpopular --- in the common use case of
6874  * partitioned tables it's a foot-gun.
6875  *
6876  * The data type must match exactly. If the parent column is NOT NULL then
6877  * the child must be as well. Defaults are not compared, however.
6878  */
6879 static void
6880 MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel)
6881 {
6882         Relation        attrrel;
6883         AttrNumber      parent_attno;
6884         int                     parent_natts;
6885         TupleDesc       tupleDesc;
6886         TupleConstr *constr;
6887         HeapTuple       tuple;
6888
6889         attrrel = heap_open(AttributeRelationId, RowExclusiveLock);
6890
6891         tupleDesc = RelationGetDescr(parent_rel);
6892         parent_natts = tupleDesc->natts;
6893         constr = tupleDesc->constr;
6894
6895         for (parent_attno = 1; parent_attno <= parent_natts; parent_attno++)
6896         {
6897                 Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1];
6898                 char       *attributeName = NameStr(attribute->attname);
6899
6900                 /* Ignore dropped columns in the parent. */
6901                 if (attribute->attisdropped)
6902                         continue;
6903
6904                 /* Find same column in child (matching on column name). */
6905                 tuple = SearchSysCacheCopyAttName(RelationGetRelid(child_rel),
6906                                                                                   attributeName);
6907                 if (HeapTupleIsValid(tuple))
6908                 {
6909                         /* Check they are same type and typmod */
6910                         Form_pg_attribute childatt = (Form_pg_attribute) GETSTRUCT(tuple);
6911
6912                         if (attribute->atttypid != childatt->atttypid ||
6913                                 attribute->atttypmod != childatt->atttypmod)
6914                                 ereport(ERROR,
6915                                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
6916                                                  errmsg("child table \"%s\" has different type for column \"%s\"",
6917                                                                 RelationGetRelationName(child_rel),
6918                                                                 attributeName)));
6919
6920                         if (attribute->attnotnull && !childatt->attnotnull)
6921                                 ereport(ERROR,
6922                                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
6923                                 errmsg("column \"%s\" in child table must be marked NOT NULL",
6924                                            attributeName)));
6925
6926                         /*
6927                          * OK, bump the child column's inheritance count.  (If we fail
6928                          * later on, this change will just roll back.)
6929                          */
6930                         childatt->attinhcount++;
6931                         simple_heap_update(attrrel, &tuple->t_self, tuple);
6932                         CatalogUpdateIndexes(attrrel, tuple);
6933                         heap_freetuple(tuple);
6934                 }
6935                 else
6936                 {
6937                         ereport(ERROR,
6938                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
6939                                          errmsg("child table is missing column \"%s\"",
6940                                                         attributeName)));
6941                 }
6942         }
6943
6944         heap_close(attrrel, RowExclusiveLock);
6945 }
6946
6947 /*
6948  * Check constraints in child table match up with constraints in parent,
6949  * and increment their coninhcount.
6950  *
6951  * Called by ATExecAddInherit
6952  *
6953  * Currently all constraints in parent must be present in the child. One day we
6954  * may consider adding new constraints like CREATE TABLE does. We may also want
6955  * to allow an optional flag on parent table constraints indicating they are
6956  * intended to ONLY apply to the master table, not to the children. That would
6957  * make it possible to ensure no records are mistakenly inserted into the
6958  * master in partitioned tables rather than the appropriate child.
6959  *
6960  * XXX This is O(N^2) which may be an issue with tables with hundreds of
6961  * constraints. As long as tables have more like 10 constraints it shouldn't be
6962  * a problem though. Even 100 constraints ought not be the end of the world.
6963  */
6964 static void
6965 MergeConstraintsIntoExisting(Relation child_rel, Relation parent_rel)
6966 {
6967         Relation        catalog_relation;
6968         TupleDesc       tuple_desc;
6969         SysScanDesc parent_scan;
6970         ScanKeyData parent_key;
6971         HeapTuple       parent_tuple;
6972
6973         catalog_relation = heap_open(ConstraintRelationId, RowExclusiveLock);
6974         tuple_desc = RelationGetDescr(catalog_relation);
6975
6976         /* Outer loop scans through the parent's constraint definitions */
6977         ScanKeyInit(&parent_key,
6978                                 Anum_pg_constraint_conrelid,
6979                                 BTEqualStrategyNumber, F_OIDEQ,
6980                                 ObjectIdGetDatum(RelationGetRelid(parent_rel)));
6981         parent_scan = systable_beginscan(catalog_relation, ConstraintRelidIndexId,
6982                                                                          true, SnapshotNow, 1, &parent_key);
6983
6984         while (HeapTupleIsValid(parent_tuple = systable_getnext(parent_scan)))
6985         {
6986                 Form_pg_constraint      parent_con = (Form_pg_constraint) GETSTRUCT(parent_tuple);
6987                 SysScanDesc                     child_scan;
6988                 ScanKeyData                     child_key;
6989                 HeapTuple                       child_tuple;
6990                 bool                            found = false;
6991
6992                 if (parent_con->contype != CONSTRAINT_CHECK)
6993                         continue;
6994
6995                 /* Search for a child constraint matching this one */
6996                 ScanKeyInit(&child_key,
6997                                         Anum_pg_constraint_conrelid,
6998                                         BTEqualStrategyNumber, F_OIDEQ,
6999                                         ObjectIdGetDatum(RelationGetRelid(child_rel)));
7000                 child_scan = systable_beginscan(catalog_relation, ConstraintRelidIndexId,
7001                                                                                 true, SnapshotNow, 1, &child_key);
7002
7003                 while (HeapTupleIsValid(child_tuple = systable_getnext(child_scan)))
7004                 {
7005                         Form_pg_constraint      child_con = (Form_pg_constraint) GETSTRUCT(child_tuple);
7006                         HeapTuple child_copy;
7007
7008                         if (child_con->contype != CONSTRAINT_CHECK)
7009                                 continue;
7010
7011                         if (strcmp(NameStr(parent_con->conname),
7012                                            NameStr(child_con->conname)) != 0)
7013                                 continue;
7014
7015                         if (!constraints_equivalent(parent_tuple, child_tuple, tuple_desc))
7016                                 ereport(ERROR,
7017                                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
7018                                                  errmsg("child table \"%s\" has different definition for check constraint \"%s\"",
7019                                                                 RelationGetRelationName(child_rel),
7020                                                                 NameStr(parent_con->conname))));
7021
7022                         /*
7023                          * OK, bump the child constraint's inheritance count.  (If we fail
7024                          * later on, this change will just roll back.)
7025                          */
7026                         child_copy = heap_copytuple(child_tuple);
7027                         child_con = (Form_pg_constraint) GETSTRUCT(child_copy);
7028                         child_con->coninhcount++;
7029                         simple_heap_update(catalog_relation, &child_copy->t_self, child_copy);
7030                         CatalogUpdateIndexes(catalog_relation, child_copy);
7031                         heap_freetuple(child_copy);
7032
7033                         found = true;
7034                         break;
7035                 }
7036
7037                 systable_endscan(child_scan);
7038
7039                 if (!found)
7040                         ereport(ERROR,
7041                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
7042                                          errmsg("child table is missing constraint \"%s\"",
7043                                                         NameStr(parent_con->conname))));
7044         }
7045
7046         systable_endscan(parent_scan);
7047         heap_close(catalog_relation, RowExclusiveLock);
7048 }
7049
7050 /*
7051  * ALTER TABLE NO INHERIT
7052  *
7053  * Drop a parent from the child's parents. This just adjusts the attinhcount
7054  * and attislocal of the columns and removes the pg_inherit and pg_depend
7055  * entries.
7056  *
7057  * If attinhcount goes to 0 then attislocal gets set to true. If it goes back
7058  * up attislocal stays true, which means if a child is ever removed from a
7059  * parent then its columns will never be automatically dropped which may
7060  * surprise. But at least we'll never surprise by dropping columns someone
7061  * isn't expecting to be dropped which would actually mean data loss.
7062  *
7063  * coninhcount and conislocal for inherited constraints are adjusted in
7064  * exactly the same way.
7065  */
7066 static void
7067 ATExecDropInherit(Relation rel, RangeVar *parent)
7068 {
7069         Relation        parent_rel;
7070         Relation        catalogRelation;
7071         SysScanDesc scan;
7072         ScanKeyData key[3];
7073         HeapTuple       inheritsTuple,
7074                                 attributeTuple,
7075                                 constraintTuple,
7076                                 depTuple;
7077         List       *connames;
7078         bool            found = false;
7079
7080         /*
7081          * AccessShareLock on the parent is probably enough, seeing that DROP
7082          * TABLE doesn't lock parent tables at all.  We need some lock since we'll
7083          * be inspecting the parent's schema.
7084          */
7085         parent_rel = heap_openrv(parent, AccessShareLock);
7086
7087         /*
7088          * We don't bother to check ownership of the parent table --- ownership of
7089          * the child is presumed enough rights.
7090          */
7091
7092         /*
7093          * Find and destroy the pg_inherits entry linking the two, or error out if
7094          * there is none.
7095          */
7096         catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock);
7097         ScanKeyInit(&key[0],
7098                                 Anum_pg_inherits_inhrelid,
7099                                 BTEqualStrategyNumber, F_OIDEQ,
7100                                 ObjectIdGetDatum(RelationGetRelid(rel)));
7101         scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId,
7102                                                           true, SnapshotNow, 1, key);
7103
7104         while (HeapTupleIsValid(inheritsTuple = systable_getnext(scan)))
7105         {
7106                 Oid                     inhparent;
7107
7108                 inhparent = ((Form_pg_inherits) GETSTRUCT(inheritsTuple))->inhparent;
7109                 if (inhparent == RelationGetRelid(parent_rel))
7110                 {
7111                         simple_heap_delete(catalogRelation, &inheritsTuple->t_self);
7112                         found = true;
7113                         break;
7114                 }
7115         }
7116
7117         systable_endscan(scan);
7118         heap_close(catalogRelation, RowExclusiveLock);
7119
7120         if (!found)
7121                 ereport(ERROR,
7122                                 (errcode(ERRCODE_UNDEFINED_TABLE),
7123                                  errmsg("relation \"%s\" is not a parent of relation \"%s\"",
7124                                                 RelationGetRelationName(parent_rel),
7125                                                 RelationGetRelationName(rel))));
7126
7127         /*
7128          * Search through child columns looking for ones matching parent rel
7129          */
7130         catalogRelation = heap_open(AttributeRelationId, RowExclusiveLock);
7131         ScanKeyInit(&key[0],
7132                                 Anum_pg_attribute_attrelid,
7133                                 BTEqualStrategyNumber, F_OIDEQ,
7134                                 ObjectIdGetDatum(RelationGetRelid(rel)));
7135         scan = systable_beginscan(catalogRelation, AttributeRelidNumIndexId,
7136                                                           true, SnapshotNow, 1, key);
7137         while (HeapTupleIsValid(attributeTuple = systable_getnext(scan)))
7138         {
7139                 Form_pg_attribute att = (Form_pg_attribute) GETSTRUCT(attributeTuple);
7140
7141                 /* Ignore if dropped or not inherited */
7142                 if (att->attisdropped)
7143                         continue;
7144                 if (att->attinhcount <= 0)
7145                         continue;
7146
7147                 if (SearchSysCacheExistsAttName(RelationGetRelid(parent_rel),
7148                                                                                 NameStr(att->attname)))
7149                 {
7150                         /* Decrement inhcount and possibly set islocal to true */
7151                         HeapTuple       copyTuple = heap_copytuple(attributeTuple);
7152                         Form_pg_attribute copy_att = (Form_pg_attribute) GETSTRUCT(copyTuple);
7153
7154                         copy_att->attinhcount--;
7155                         if (copy_att->attinhcount == 0)
7156                                 copy_att->attislocal = true;
7157
7158                         simple_heap_update(catalogRelation, &copyTuple->t_self, copyTuple);
7159                         CatalogUpdateIndexes(catalogRelation, copyTuple);
7160                         heap_freetuple(copyTuple);
7161                 }
7162         }
7163         systable_endscan(scan);
7164         heap_close(catalogRelation, RowExclusiveLock);
7165
7166         /*
7167          * Likewise, find inherited check constraints and disinherit them.
7168          * To do this, we first need a list of the names of the parent's check
7169          * constraints.  (We cheat a bit by only checking for name matches,
7170          * assuming that the expressions will match.)
7171          */
7172         catalogRelation = heap_open(ConstraintRelationId, RowExclusiveLock);
7173         ScanKeyInit(&key[0],
7174                                 Anum_pg_constraint_conrelid,
7175                                 BTEqualStrategyNumber, F_OIDEQ,
7176                                 ObjectIdGetDatum(RelationGetRelid(parent_rel)));
7177         scan = systable_beginscan(catalogRelation, ConstraintRelidIndexId,
7178                                                           true, SnapshotNow, 1, key);
7179
7180         connames = NIL;
7181
7182         while (HeapTupleIsValid(constraintTuple = systable_getnext(scan)))
7183         {
7184                 Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(constraintTuple);
7185
7186                 if (con->contype == CONSTRAINT_CHECK)
7187                         connames = lappend(connames, pstrdup(NameStr(con->conname)));
7188         }
7189
7190         systable_endscan(scan);
7191
7192         /* Now scan the child's constraints */
7193         ScanKeyInit(&key[0],
7194                                 Anum_pg_constraint_conrelid,
7195                                 BTEqualStrategyNumber, F_OIDEQ,
7196                                 ObjectIdGetDatum(RelationGetRelid(rel)));
7197         scan = systable_beginscan(catalogRelation, ConstraintRelidIndexId,
7198                                                           true, SnapshotNow, 1, key);
7199
7200         while (HeapTupleIsValid(constraintTuple = systable_getnext(scan)))
7201         {
7202                 Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(constraintTuple);
7203                 bool    match;
7204                 ListCell *lc;
7205
7206                 if (con->contype != CONSTRAINT_CHECK)
7207                         continue;
7208
7209                 match = false;
7210                 foreach (lc, connames)
7211                 {
7212                         if (strcmp(NameStr(con->conname), (char *) lfirst(lc)) == 0)
7213                         {
7214                                 match = true;
7215                                 break;
7216                         }
7217                 }
7218
7219                 if (match)
7220                 {
7221                         /* Decrement inhcount and possibly set islocal to true */
7222                         HeapTuple       copyTuple = heap_copytuple(constraintTuple);
7223                         Form_pg_constraint copy_con = (Form_pg_constraint) GETSTRUCT(copyTuple);
7224                         if (copy_con->coninhcount <= 0)         /* shouldn't happen */
7225                                 elog(ERROR, "relation %u has non-inherited constraint \"%s\"",
7226                                          RelationGetRelid(rel), NameStr(copy_con->conname));
7227
7228                         copy_con->coninhcount--;
7229                         if (copy_con->coninhcount == 0)
7230                                 copy_con->conislocal = true;
7231
7232                         simple_heap_update(catalogRelation, &copyTuple->t_self, copyTuple);
7233                         CatalogUpdateIndexes(catalogRelation, copyTuple);
7234                         heap_freetuple(copyTuple);
7235                 }
7236         }
7237
7238         systable_endscan(scan);
7239         heap_close(catalogRelation, RowExclusiveLock);
7240
7241         /*
7242          * Drop the dependency
7243          *
7244          * There's no convenient way to do this, so go trawling through pg_depend
7245          */
7246         catalogRelation = heap_open(DependRelationId, RowExclusiveLock);
7247
7248         ScanKeyInit(&key[0],
7249                                 Anum_pg_depend_classid,
7250                                 BTEqualStrategyNumber, F_OIDEQ,
7251                                 ObjectIdGetDatum(RelationRelationId));
7252         ScanKeyInit(&key[1],
7253                                 Anum_pg_depend_objid,
7254                                 BTEqualStrategyNumber, F_OIDEQ,
7255                                 ObjectIdGetDatum(RelationGetRelid(rel)));
7256         ScanKeyInit(&key[2],
7257                                 Anum_pg_depend_objsubid,
7258                                 BTEqualStrategyNumber, F_INT4EQ,
7259                                 Int32GetDatum(0));
7260
7261         scan = systable_beginscan(catalogRelation, DependDependerIndexId, true,
7262                                                           SnapshotNow, 3, key);
7263
7264         while (HeapTupleIsValid(depTuple = systable_getnext(scan)))
7265         {
7266                 Form_pg_depend dep = (Form_pg_depend) GETSTRUCT(depTuple);
7267
7268                 if (dep->refclassid == RelationRelationId &&
7269                         dep->refobjid == RelationGetRelid(parent_rel) &&
7270                         dep->refobjsubid == 0 &&
7271                         dep->deptype == DEPENDENCY_NORMAL)
7272                         simple_heap_delete(catalogRelation, &depTuple->t_self);
7273         }
7274
7275         systable_endscan(scan);
7276         heap_close(catalogRelation, RowExclusiveLock);
7277
7278         /* keep our lock on the parent relation until commit */
7279         heap_close(parent_rel, NoLock);
7280 }
7281
7282
7283 /*
7284  * Execute ALTER TABLE SET SCHEMA
7285  *
7286  * Note: caller must have checked ownership of the relation already
7287  */
7288 void
7289 AlterTableNamespace(RangeVar *relation, const char *newschema,
7290                                         ObjectType stmttype)
7291 {
7292         Relation        rel;
7293         Oid                     relid;
7294         Oid                     oldNspOid;
7295         Oid                     nspOid;
7296         Relation        classRel;
7297
7298         rel = relation_openrv(relation, AccessExclusiveLock);
7299
7300         relid = RelationGetRelid(rel);
7301         oldNspOid = RelationGetNamespace(rel);
7302
7303         /* Check relation type against type specified in the ALTER command */
7304         switch (stmttype)
7305         {
7306                 case OBJECT_TABLE:
7307                         /*
7308                          * For mostly-historical reasons, we allow ALTER TABLE to apply
7309                          * to all relation types.
7310                          */
7311                         break;
7312
7313                 case OBJECT_SEQUENCE:
7314                         if (rel->rd_rel->relkind != RELKIND_SEQUENCE)
7315                                 ereport(ERROR,
7316                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
7317                                                  errmsg("\"%s\" is not a sequence",
7318                                                                 RelationGetRelationName(rel))));
7319                         break;
7320
7321                 case OBJECT_VIEW:
7322                         if (rel->rd_rel->relkind != RELKIND_VIEW)
7323                                 ereport(ERROR,
7324                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
7325                                                  errmsg("\"%s\" is not a view",
7326                                                                 RelationGetRelationName(rel))));
7327                         break;
7328
7329                 default:
7330                         elog(ERROR, "unrecognized object type: %d", (int) stmttype);
7331         }
7332
7333         /* Can we change the schema of this tuple? */
7334         switch (rel->rd_rel->relkind)
7335         {
7336                 case RELKIND_RELATION:
7337                 case RELKIND_VIEW:
7338                         /* ok to change schema */
7339                         break;
7340                 case RELKIND_SEQUENCE:
7341                         {
7342                                 /* if it's an owned sequence, disallow moving it by itself */
7343                                 Oid                     tableId;
7344                                 int32           colId;
7345
7346                                 if (sequenceIsOwned(relid, &tableId, &colId))
7347                                         ereport(ERROR,
7348                                                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
7349                                                          errmsg("cannot move an owned sequence into another schema"),
7350                                           errdetail("Sequence \"%s\" is linked to table \"%s\".",
7351                                                                 RelationGetRelationName(rel),
7352                                                                 get_rel_name(tableId))));
7353                         }
7354                         break;
7355                 case RELKIND_COMPOSITE_TYPE:
7356                         ereport(ERROR,
7357                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
7358                                          errmsg("\"%s\" is a composite type",
7359                                                         RelationGetRelationName(rel)),
7360                                          errhint("Use ALTER TYPE instead.")));
7361                         break;
7362                 case RELKIND_INDEX:
7363                 case RELKIND_TOASTVALUE:
7364                         /* FALL THRU */
7365                 default:
7366                         ereport(ERROR,
7367                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
7368                                          errmsg("\"%s\" is not a table, view, or sequence",
7369                                                         RelationGetRelationName(rel))));
7370         }
7371
7372         /* get schema OID and check its permissions */
7373         nspOid = LookupCreationNamespace(newschema);
7374
7375         if (oldNspOid == nspOid)
7376                 ereport(ERROR,
7377                                 (errcode(ERRCODE_DUPLICATE_TABLE),
7378                                  errmsg("relation \"%s\" is already in schema \"%s\"",
7379                                                 RelationGetRelationName(rel),
7380                                                 newschema)));
7381
7382         /* disallow renaming into or out of temp schemas */
7383         if (isAnyTempNamespace(nspOid) || isAnyTempNamespace(oldNspOid))
7384                 ereport(ERROR,
7385                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
7386                         errmsg("cannot move objects into or out of temporary schemas")));
7387
7388         /* same for TOAST schema */
7389         if (nspOid == PG_TOAST_NAMESPACE || oldNspOid == PG_TOAST_NAMESPACE)
7390                 ereport(ERROR,
7391                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
7392                                  errmsg("cannot move objects into or out of TOAST schema")));
7393
7394         /* OK, modify the pg_class row and pg_depend entry */
7395         classRel = heap_open(RelationRelationId, RowExclusiveLock);
7396
7397         AlterRelationNamespaceInternal(classRel, relid, oldNspOid, nspOid, true);
7398
7399         /* Fix the table's rowtype too */
7400         AlterTypeNamespaceInternal(rel->rd_rel->reltype, nspOid, false, false);
7401
7402         /* Fix other dependent stuff */
7403         if (rel->rd_rel->relkind == RELKIND_RELATION)
7404         {
7405                 AlterIndexNamespaces(classRel, rel, oldNspOid, nspOid);
7406                 AlterSeqNamespaces(classRel, rel, oldNspOid, nspOid, newschema);
7407                 AlterConstraintNamespaces(relid, oldNspOid, nspOid, false);
7408         }
7409
7410         heap_close(classRel, RowExclusiveLock);
7411
7412         /* close rel, but keep lock until commit */
7413         relation_close(rel, NoLock);
7414 }
7415
7416 /*
7417  * The guts of relocating a relation to another namespace: fix the pg_class
7418  * entry, and the pg_depend entry if any.  Caller must already have
7419  * opened and write-locked pg_class.
7420  */
7421 void
7422 AlterRelationNamespaceInternal(Relation classRel, Oid relOid,
7423                                                            Oid oldNspOid, Oid newNspOid,
7424                                                            bool hasDependEntry)
7425 {
7426         HeapTuple       classTup;
7427         Form_pg_class classForm;
7428
7429         classTup = SearchSysCacheCopy(RELOID,
7430                                                                   ObjectIdGetDatum(relOid),
7431                                                                   0, 0, 0);
7432         if (!HeapTupleIsValid(classTup))
7433                 elog(ERROR, "cache lookup failed for relation %u", relOid);
7434         classForm = (Form_pg_class) GETSTRUCT(classTup);
7435
7436         Assert(classForm->relnamespace == oldNspOid);
7437
7438         /* check for duplicate name (more friendly than unique-index failure) */
7439         if (get_relname_relid(NameStr(classForm->relname),
7440                                                   newNspOid) != InvalidOid)
7441                 ereport(ERROR,
7442                                 (errcode(ERRCODE_DUPLICATE_TABLE),
7443                                  errmsg("relation \"%s\" already exists in schema \"%s\"",
7444                                                 NameStr(classForm->relname),
7445                                                 get_namespace_name(newNspOid))));
7446
7447         /* classTup is a copy, so OK to scribble on */
7448         classForm->relnamespace = newNspOid;
7449
7450         simple_heap_update(classRel, &classTup->t_self, classTup);
7451         CatalogUpdateIndexes(classRel, classTup);
7452
7453         /* Update dependency on schema if caller said so */
7454         if (hasDependEntry &&
7455                 changeDependencyFor(RelationRelationId, relOid,
7456                                                         NamespaceRelationId, oldNspOid, newNspOid) != 1)
7457                 elog(ERROR, "failed to change schema dependency for relation \"%s\"",
7458                          NameStr(classForm->relname));
7459
7460         heap_freetuple(classTup);
7461 }
7462
7463 /*
7464  * Move all indexes for the specified relation to another namespace.
7465  *
7466  * Note: we assume adequate permission checking was done by the caller,
7467  * and that the caller has a suitable lock on the owning relation.
7468  */
7469 static void
7470 AlterIndexNamespaces(Relation classRel, Relation rel,
7471                                          Oid oldNspOid, Oid newNspOid)
7472 {
7473         List       *indexList;
7474         ListCell   *l;
7475
7476         indexList = RelationGetIndexList(rel);
7477
7478         foreach(l, indexList)
7479         {
7480                 Oid                     indexOid = lfirst_oid(l);
7481
7482                 /*
7483                  * Note: currently, the index will not have its own dependency on the
7484                  * namespace, so we don't need to do changeDependencyFor(). There's no
7485                  * rowtype in pg_type, either.
7486                  */
7487                 AlterRelationNamespaceInternal(classRel, indexOid,
7488                                                                            oldNspOid, newNspOid,
7489                                                                            false);
7490         }
7491
7492         list_free(indexList);
7493 }
7494
7495 /*
7496  * Move all SERIAL-column sequences of the specified relation to another
7497  * namespace.
7498  *
7499  * Note: we assume adequate permission checking was done by the caller,
7500  * and that the caller has a suitable lock on the owning relation.
7501  */
7502 static void
7503 AlterSeqNamespaces(Relation classRel, Relation rel,
7504                                    Oid oldNspOid, Oid newNspOid, const char *newNspName)
7505 {
7506         Relation        depRel;
7507         SysScanDesc scan;
7508         ScanKeyData key[2];
7509         HeapTuple       tup;
7510
7511         /*
7512          * SERIAL sequences are those having an auto dependency on one of the
7513          * table's columns (we don't care *which* column, exactly).
7514          */
7515         depRel = heap_open(DependRelationId, AccessShareLock);
7516
7517         ScanKeyInit(&key[0],
7518                                 Anum_pg_depend_refclassid,
7519                                 BTEqualStrategyNumber, F_OIDEQ,
7520                                 ObjectIdGetDatum(RelationRelationId));
7521         ScanKeyInit(&key[1],
7522                                 Anum_pg_depend_refobjid,
7523                                 BTEqualStrategyNumber, F_OIDEQ,
7524                                 ObjectIdGetDatum(RelationGetRelid(rel)));
7525         /* we leave refobjsubid unspecified */
7526
7527         scan = systable_beginscan(depRel, DependReferenceIndexId, true,
7528                                                           SnapshotNow, 2, key);
7529
7530         while (HeapTupleIsValid(tup = systable_getnext(scan)))
7531         {
7532                 Form_pg_depend depForm = (Form_pg_depend) GETSTRUCT(tup);
7533                 Relation        seqRel;
7534
7535                 /* skip dependencies other than auto dependencies on columns */
7536                 if (depForm->refobjsubid == 0 ||
7537                         depForm->classid != RelationRelationId ||
7538                         depForm->objsubid != 0 ||
7539                         depForm->deptype != DEPENDENCY_AUTO)
7540                         continue;
7541
7542                 /* Use relation_open just in case it's an index */
7543                 seqRel = relation_open(depForm->objid, AccessExclusiveLock);
7544
7545                 /* skip non-sequence relations */
7546                 if (RelationGetForm(seqRel)->relkind != RELKIND_SEQUENCE)
7547                 {
7548                         /* No need to keep the lock */
7549                         relation_close(seqRel, AccessExclusiveLock);
7550                         continue;
7551                 }
7552
7553                 /* Fix the pg_class and pg_depend entries */
7554                 AlterRelationNamespaceInternal(classRel, depForm->objid,
7555                                                                            oldNspOid, newNspOid,
7556                                                                            true);
7557
7558                 /*
7559                  * Sequences have entries in pg_type. We need to be careful to move
7560                  * them to the new namespace, too.
7561                  */
7562                 AlterTypeNamespaceInternal(RelationGetForm(seqRel)->reltype,
7563                                                                    newNspOid, false, false);
7564
7565                 /* Now we can close it.  Keep the lock till end of transaction. */
7566                 relation_close(seqRel, NoLock);
7567         }
7568
7569         systable_endscan(scan);
7570
7571         relation_close(depRel, AccessShareLock);
7572 }
7573
7574
7575 /*
7576  * This code supports
7577  *      CREATE TEMP TABLE ... ON COMMIT { DROP | PRESERVE ROWS | DELETE ROWS }
7578  *
7579  * Because we only support this for TEMP tables, it's sufficient to remember
7580  * the state in a backend-local data structure.
7581  */
7582
7583 /*
7584  * Register a newly-created relation's ON COMMIT action.
7585  */
7586 void
7587 register_on_commit_action(Oid relid, OnCommitAction action)
7588 {
7589         OnCommitItem *oc;
7590         MemoryContext oldcxt;
7591
7592         /*
7593          * We needn't bother registering the relation unless there is an ON COMMIT
7594          * action we need to take.
7595          */
7596         if (action == ONCOMMIT_NOOP || action == ONCOMMIT_PRESERVE_ROWS)
7597                 return;
7598
7599         oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
7600
7601         oc = (OnCommitItem *) palloc(sizeof(OnCommitItem));
7602         oc->relid = relid;
7603         oc->oncommit = action;
7604         oc->creating_subid = GetCurrentSubTransactionId();
7605         oc->deleting_subid = InvalidSubTransactionId;
7606
7607         on_commits = lcons(oc, on_commits);
7608
7609         MemoryContextSwitchTo(oldcxt);
7610 }
7611
7612 /*
7613  * Unregister any ON COMMIT action when a relation is deleted.
7614  *
7615  * Actually, we only mark the OnCommitItem entry as to be deleted after commit.
7616  */
7617 void
7618 remove_on_commit_action(Oid relid)
7619 {
7620         ListCell   *l;
7621
7622         foreach(l, on_commits)
7623         {
7624                 OnCommitItem *oc = (OnCommitItem *) lfirst(l);
7625
7626                 if (oc->relid == relid)
7627                 {
7628                         oc->deleting_subid = GetCurrentSubTransactionId();
7629                         break;
7630                 }
7631         }
7632 }
7633
7634 /*
7635  * Perform ON COMMIT actions.
7636  *
7637  * This is invoked just before actually committing, since it's possible
7638  * to encounter errors.
7639  */
7640 void
7641 PreCommit_on_commit_actions(void)
7642 {
7643         ListCell   *l;
7644         List       *oids_to_truncate = NIL;
7645
7646         foreach(l, on_commits)
7647         {
7648                 OnCommitItem *oc = (OnCommitItem *) lfirst(l);
7649
7650                 /* Ignore entry if already dropped in this xact */
7651                 if (oc->deleting_subid != InvalidSubTransactionId)
7652                         continue;
7653
7654                 switch (oc->oncommit)
7655                 {
7656                         case ONCOMMIT_NOOP:
7657                         case ONCOMMIT_PRESERVE_ROWS:
7658                                 /* Do nothing (there shouldn't be such entries, actually) */
7659                                 break;
7660                         case ONCOMMIT_DELETE_ROWS:
7661                                 oids_to_truncate = lappend_oid(oids_to_truncate, oc->relid);
7662                                 break;
7663                         case ONCOMMIT_DROP:
7664                                 {
7665                                         ObjectAddress object;
7666
7667                                         object.classId = RelationRelationId;
7668                                         object.objectId = oc->relid;
7669                                         object.objectSubId = 0;
7670                                         performDeletion(&object, DROP_CASCADE);
7671
7672                                         /*
7673                                          * Note that table deletion will call
7674                                          * remove_on_commit_action, so the entry should get marked
7675                                          * as deleted.
7676                                          */
7677                                         Assert(oc->deleting_subid != InvalidSubTransactionId);
7678                                         break;
7679                                 }
7680                 }
7681         }
7682         if (oids_to_truncate != NIL)
7683         {
7684                 heap_truncate(oids_to_truncate);
7685                 CommandCounterIncrement();              /* XXX needed? */
7686         }
7687 }
7688
7689 /*
7690  * Post-commit or post-abort cleanup for ON COMMIT management.
7691  *
7692  * All we do here is remove no-longer-needed OnCommitItem entries.
7693  *
7694  * During commit, remove entries that were deleted during this transaction;
7695  * during abort, remove those created during this transaction.
7696  */
7697 void
7698 AtEOXact_on_commit_actions(bool isCommit)
7699 {
7700         ListCell   *cur_item;
7701         ListCell   *prev_item;
7702
7703         prev_item = NULL;
7704         cur_item = list_head(on_commits);
7705
7706         while (cur_item != NULL)
7707         {
7708                 OnCommitItem *oc = (OnCommitItem *) lfirst(cur_item);
7709
7710                 if (isCommit ? oc->deleting_subid != InvalidSubTransactionId :
7711                         oc->creating_subid != InvalidSubTransactionId)
7712                 {
7713                         /* cur_item must be removed */
7714                         on_commits = list_delete_cell(on_commits, cur_item, prev_item);
7715                         pfree(oc);
7716                         if (prev_item)
7717                                 cur_item = lnext(prev_item);
7718                         else
7719                                 cur_item = list_head(on_commits);
7720                 }
7721                 else
7722                 {
7723                         /* cur_item must be preserved */
7724                         oc->creating_subid = InvalidSubTransactionId;
7725                         oc->deleting_subid = InvalidSubTransactionId;
7726                         prev_item = cur_item;
7727                         cur_item = lnext(prev_item);
7728                 }
7729         }
7730 }
7731
7732 /*
7733  * Post-subcommit or post-subabort cleanup for ON COMMIT management.
7734  *
7735  * During subabort, we can immediately remove entries created during this
7736  * subtransaction.      During subcommit, just relabel entries marked during
7737  * this subtransaction as being the parent's responsibility.
7738  */
7739 void
7740 AtEOSubXact_on_commit_actions(bool isCommit, SubTransactionId mySubid,
7741                                                           SubTransactionId parentSubid)
7742 {
7743         ListCell   *cur_item;
7744         ListCell   *prev_item;
7745
7746         prev_item = NULL;
7747         cur_item = list_head(on_commits);
7748
7749         while (cur_item != NULL)
7750         {
7751                 OnCommitItem *oc = (OnCommitItem *) lfirst(cur_item);
7752
7753                 if (!isCommit && oc->creating_subid == mySubid)
7754                 {
7755                         /* cur_item must be removed */
7756                         on_commits = list_delete_cell(on_commits, cur_item, prev_item);
7757                         pfree(oc);
7758                         if (prev_item)
7759                                 cur_item = lnext(prev_item);
7760                         else
7761                                 cur_item = list_head(on_commits);
7762                 }
7763                 else
7764                 {
7765                         /* cur_item must be preserved */
7766                         if (oc->creating_subid == mySubid)
7767                                 oc->creating_subid = parentSubid;
7768                         if (oc->deleting_subid == mySubid)
7769                                 oc->deleting_subid = isCommit ? parentSubid : InvalidSubTransactionId;
7770                         prev_item = cur_item;
7771                         cur_item = lnext(prev_item);
7772                 }
7773         }
7774 }