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) 1996-2006, 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 1.189 2006/07/02 01:58:36 momjian Exp $
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include "access/genam.h"
  18 #include "access/tuptoaster.h"
  19 #include "catalog/catalog.h"
  20 #include "catalog/dependency.h"
  21 #include "catalog/heap.h"
  22 #include "catalog/index.h"
  23 #include "catalog/indexing.h"
  24 #include "catalog/namespace.h"
  25 #include "catalog/pg_constraint.h"
  26 #include "catalog/pg_depend.h"
  27 #include "catalog/pg_inherits.h"
  28 #include "catalog/pg_namespace.h"
  29 #include "catalog/pg_opclass.h"
  30 #include "catalog/pg_trigger.h"
  31 #include "catalog/pg_type.h"
  32 #include "commands/cluster.h"
  33 #include "commands/defrem.h"
  34 #include "commands/tablecmds.h"
  35 #include "commands/tablespace.h"
  36 #include "commands/trigger.h"
  37 #include "commands/typecmds.h"
  38 #include "executor/executor.h"
  39 #include "lib/stringinfo.h"
  40 #include "miscadmin.h"
  41 #include "nodes/makefuncs.h"
  42 #include "optimizer/clauses.h"
  43 #include "optimizer/plancat.h"
  44 #include "optimizer/prep.h"
  45 #include "parser/analyze.h"
  46 #include "parser/gramparse.h"
  47 #include "parser/parser.h"
  48 #include "parser/parse_clause.h"
  49 #include "parser/parse_coerce.h"
  50 #include "parser/parse_expr.h"
  51 #include "parser/parse_oper.h"
  52 #include "parser/parse_relation.h"
  53 #include "parser/parse_type.h"
  54 #include "rewrite/rewriteHandler.h"
  55 #include "storage/smgr.h"
  56 #include "utils/acl.h"
  57 #include "utils/builtins.h"
  58 #include "utils/fmgroids.h"
  59 #include "utils/inval.h"
  60 #include "utils/lsyscache.h"
  61 #include "utils/memutils.h"
  62 #include "utils/relcache.h"
  63 #include "utils/syscache.h"
  64
  65
  66 /*
  67  * ON COMMIT action list
  68  */
  69 typedef struct OnCommitItem
  70 {
  71         Oid                     relid;                  /* relid of relation */
  72         OnCommitAction oncommit;        /* what to do at end of xact */
  73
  74         /*
  75          * If this entry was created during the current transaction,
  76          * creating_subid is the ID of the creating subxact; if created in a prior
  77          * transaction, creating_subid is zero.  If deleted during the current
  78          * transaction, deleting_subid is the ID of the deleting subxact; if no
  79          * deletion request is pending, deleting_subid is zero.
  80          */
  81         SubTransactionId creating_subid;
  82         SubTransactionId deleting_subid;
  83 } OnCommitItem;
  84
  85 static List *on_commits = NIL;
  86
  87
  88 /*
  89  * State information for ALTER TABLE
  90  *
  91  * The pending-work queue for an ALTER TABLE is a List of AlteredTableInfo
  92  * structs, one for each table modified by the operation (the named table
  93  * plus any child tables that are affected).  We save lists of subcommands
  94  * to apply to this table (possibly modified by parse transformation steps);
  95  * these lists will be executed in Phase 2.  If a Phase 3 step is needed,
  96  * necessary information is stored in the constraints and newvals lists.
  97  *
  98  * Phase 2 is divided into multiple passes; subcommands are executed in
  99  * a pass determined by subcommand type.
 100  */
 101
 102 #define AT_PASS_DROP                    0               /* DROP (all flavors) */
 103 #define AT_PASS_ALTER_TYPE              1               /* ALTER COLUMN TYPE */
 104 #define AT_PASS_OLD_INDEX               2               /* re-add existing indexes */
 105 #define AT_PASS_OLD_CONSTR              3               /* re-add existing constraints */
 106 #define AT_PASS_COL_ATTRS               4               /* set other column attributes */
 107 /* We could support a RENAME COLUMN pass here, but not currently used */
 108 #define AT_PASS_ADD_COL                 5               /* ADD COLUMN */
 109 #define AT_PASS_ADD_INDEX               6               /* ADD indexes */
 110 #define AT_PASS_ADD_CONSTR              7               /* ADD constraints, defaults */
 111 #define AT_PASS_MISC                    8               /* other stuff */
 112 #define AT_NUM_PASSES                   9
 113
 114 typedef struct AlteredTableInfo
 115 {
 116         /* Information saved before any work commences: */
 117         Oid                     relid;                  /* Relation to work on */
 118         char            relkind;                /* Its relkind */
 119         TupleDesc       oldDesc;                /* Pre-modification tuple descriptor */
 120         /* Information saved by Phase 1 for Phase 2: */
 121         List       *subcmds[AT_NUM_PASSES]; /* Lists of AlterTableCmd */
 122         /* Information saved by Phases 1/2 for Phase 3: */
 123         List       *constraints;        /* List of NewConstraint */
 124         List       *newvals;            /* List of NewColumnValue */
 125         Oid                     newTableSpace;  /* new tablespace; 0 means no change */
 126         /* Objects to rebuild after completing ALTER TYPE operations */
 127         List       *changedConstraintOids;      /* OIDs of constraints to rebuild */
 128         List       *changedConstraintDefs;      /* string definitions of same */
 129         List       *changedIndexOids;           /* OIDs of indexes to rebuild */
 130         List       *changedIndexDefs;           /* string definitions of same */
 131 } AlteredTableInfo;
 132
 133 /* Struct describing one new constraint to check in Phase 3 scan */
 134 typedef struct NewConstraint
 135 {
 136         char       *name;                       /* Constraint name, or NULL if none */
 137         ConstrType      contype;                /* CHECK, NOT_NULL, or FOREIGN */
 138         AttrNumber      attnum;                 /* only relevant for NOT_NULL */
 139         Oid                     refrelid;               /* PK rel, if FOREIGN */
 140         Node       *qual;                       /* Check expr or FkConstraint struct */
 141         List       *qualstate;          /* Execution state for CHECK */
 142 } NewConstraint;
 143
 144 /*
 145  * Struct describing one new column value that needs to be computed during
 146  * Phase 3 copy (this could be either a new column with a non-null default, or
 147  * a column that we're changing the type of).  Columns without such an entry
 148  * are just copied from the old table during ATRewriteTable.  Note that the
 149  * expr is an expression over *old* table values.
 150  */
 151 typedef struct NewColumnValue
 152 {
 153         AttrNumber      attnum;                 /* which column */
 154         Expr       *expr;                       /* expression to compute */
 155         ExprState  *exprstate;          /* execution state */
 156 } NewColumnValue;
 157
 158
 159 static void truncate_check_rel(Relation rel);
 160 static List *MergeAttributes(List *schema, List *supers, bool istemp,
 161                                 List **supOids, List **supconstr, int *supOidCount);
 162 static void MergeConstraintsIntoExisting(Relation rel, Relation relation);
 163 static void MergeAttributesIntoExisting(Relation rel, Relation relation);
 164 static bool change_varattnos_walker(Node *node, const AttrNumber *newattno);
 165 static void StoreCatalogInheritance(Oid relationId, List *supers);
 166 static void StoreCatalogInheritance1(Oid relationId, Oid parentOid,
 167                                         int16 seqNumber, Relation catalogRelation);
 168 static int      findAttrByName(const char *attributeName, List *schema);
 169 static void setRelhassubclassInRelation(Oid relationId, bool relhassubclass);
 170 static bool needs_toast_table(Relation rel);
 171 static void AlterIndexNamespaces(Relation classRel, Relation rel,
 172                                          Oid oldNspOid, Oid newNspOid);
 173 static void AlterSeqNamespaces(Relation classRel, Relation rel,
 174                                    Oid oldNspOid, Oid newNspOid,
 175                                    const char *newNspName);
 176 static int transformColumnNameList(Oid relId, List *colList,
 177                                                 int16 *attnums, Oid *atttypids);
 178 static int transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
 179                                                    List **attnamelist,
 180                                                    int16 *attnums, Oid *atttypids,
 181                                                    Oid *opclasses);
 182 static Oid transformFkeyCheckAttrs(Relation pkrel,
 183                                                 int numattrs, int16 *attnums,
 184                                                 Oid *opclasses);
 185 static void validateForeignKeyConstraint(FkConstraint *fkconstraint,
 186                                                          Relation rel, Relation pkrel);
 187 static void createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
 188                                                  Oid constrOid);
 189 static char *fkMatchTypeToString(char match_type);
 190 static void ATController(Relation rel, List *cmds, bool recurse);
 191 static void ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 192                   bool recurse, bool recursing);
 193 static void ATRewriteCatalogs(List **wqueue);
 194 static void ATExecCmd(AlteredTableInfo *tab, Relation rel, AlterTableCmd *cmd);
 195 static void ATRewriteTables(List **wqueue);
 196 static void ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap);
 197 static AlteredTableInfo *ATGetQueueEntry(List **wqueue, Relation rel);
 198 static void ATSimplePermissions(Relation rel, bool allowView);
 199 static void ATSimpleRecursion(List **wqueue, Relation rel,
 200                                   AlterTableCmd *cmd, bool recurse);
 201 static void ATOneLevelRecursion(List **wqueue, Relation rel,
 202                                         AlterTableCmd *cmd);
 203 static void find_composite_type_dependencies(Oid typeOid,
 204                                                                  const char *origTblName);
 205 static void ATPrepAddColumn(List **wqueue, Relation rel, bool recurse,
 206                                 AlterTableCmd *cmd);
 207 static void ATExecAddColumn(AlteredTableInfo *tab, Relation rel,
 208                                 ColumnDef *colDef);
 209 static void add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid);
 210 static void add_column_support_dependency(Oid relid, int32 attnum,
 211                                                           RangeVar *support);
 212 static void ATExecDropNotNull(Relation rel, const char *colName);
 213 static void ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 214                                  const char *colName);
 215 static void ATExecColumnDefault(Relation rel, const char *colName,
 216                                         Node *newDefault);
 217 static void ATPrepSetStatistics(Relation rel, const char *colName,
 218                                         Node *flagValue);
 219 static void ATExecSetStatistics(Relation rel, const char *colName,
 220                                         Node *newValue);
 221 static void ATExecSetStorage(Relation rel, const char *colName,
 222                                  Node *newValue);
 223 static void ATExecDropColumn(Relation rel, const char *colName,
 224                                  DropBehavior behavior,
 225                                  bool recurse, bool recursing);
 226 static void ATExecAddIndex(AlteredTableInfo *tab, Relation rel,
 227                            IndexStmt *stmt, bool is_rebuild);
 228 static void ATExecAddConstraint(AlteredTableInfo *tab, Relation rel,
 229                                         Node *newConstraint);
 230 static void ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel,
 231                                                   FkConstraint *fkconstraint);
 232 static void ATPrepDropConstraint(List **wqueue, Relation rel,
 233                                          bool recurse, AlterTableCmd *cmd);
 234 static void ATExecDropConstraint(Relation rel, const char *constrName,
 235                                          DropBehavior behavior, bool quiet);
 236 static void ATPrepAlterColumnType(List **wqueue,
 237                                           AlteredTableInfo *tab, Relation rel,
 238                                           bool recurse, bool recursing,
 239                                           AlterTableCmd *cmd);
 240 static void ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
 241                                           const char *colName, TypeName *typename);
 242 static void ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab);
 243 static void ATPostAlterTypeParse(char *cmd, List **wqueue);
 244 static void change_owner_recurse_to_sequences(Oid relationOid,
 245                                                                   Oid newOwnerId);
 246 static void ATExecClusterOn(Relation rel, const char *indexName);
 247 static void ATExecDropCluster(Relation rel);
 248 static void ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel,
 249                                         char *tablespacename);
 250 static void ATExecSetTableSpace(Oid tableOid, Oid newTableSpace);
 251 static void ATExecEnableDisableTrigger(Relation rel, char *trigname,
 252                                                    bool enable, bool skip_system);
 253 static void ATExecAddInherits(Relation rel, RangeVar *parent);
 254 static void ATExecDropInherits(Relation rel, RangeVar *parent);
 255 static void copy_relation_data(Relation rel, SMgrRelation dst);
 256 static void update_ri_trigger_args(Oid relid,
 257                                            const char *oldname,
 258                                            const char *newname,
 259                                            bool fk_scan,
 260                                            bool update_relname);
 261
 262
 263 /* ----------------------------------------------------------------
 264  *              DefineRelation
 265  *                              Creates a new relation.
 266  *
 267  * If successful, returns the OID of the new relation.
 268  * ----------------------------------------------------------------
 269  */
 270 Oid
 271 DefineRelation(CreateStmt *stmt, char relkind)
 272 {
 273         char            relname[NAMEDATALEN];
 274         Oid                     namespaceId;
 275         List       *schema = stmt->tableElts;
 276         Oid                     relationId;
 277         Oid                     tablespaceId;
 278         Relation        rel;
 279         TupleDesc       descriptor;
 280         List       *inheritOids;
 281         List       *old_constraints;
 282         bool            localHasOids;
 283         int                     parentOidCount;
 284         List       *rawDefaults;
 285         ListCell   *listptr;
 286         int                     i;
 287         AttrNumber      attnum;
 288
 289         /*
 290          * Truncate relname to appropriate length (probably a waste of time, as
 291          * parser should have done this already).
 292          */
 293         StrNCpy(relname, stmt->relation->relname, NAMEDATALEN);
 294
 295         /*
 296          * Check consistency of arguments
 297          */
 298         if (stmt->oncommit != ONCOMMIT_NOOP && !stmt->relation->istemp)
 299                 ereport(ERROR,
 300                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 301                                  errmsg("ON COMMIT can only be used on temporary tables")));
 302
 303         /*
 304          * Look up the namespace in which we are supposed to create the relation.
 305          * Check we have permission to create there. Skip check if bootstrapping,
 306          * since permissions machinery may not be working yet.
 307          */
 308         namespaceId = RangeVarGetCreationNamespace(stmt->relation);
 309
 310         if (!IsBootstrapProcessingMode())
 311         {
 312                 AclResult       aclresult;
 313
 314                 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
 315                                                                                   ACL_CREATE);
 316                 if (aclresult != ACLCHECK_OK)
 317                         aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
 318                                                    get_namespace_name(namespaceId));
 319         }
 320
 321         /*
 322          * Select tablespace to use.  If not specified, use default_tablespace
 323          * (which may in turn default to database's default).
 324          */
 325         if (stmt->tablespacename)
 326         {
 327                 tablespaceId = get_tablespace_oid(stmt->tablespacename);
 328                 if (!OidIsValid(tablespaceId))
 329                         ereport(ERROR,
 330                                         (errcode(ERRCODE_UNDEFINED_OBJECT),
 331                                          errmsg("tablespace \"%s\" does not exist",
 332                                                         stmt->tablespacename)));
 333         }
 334         else
 335         {
 336                 tablespaceId = GetDefaultTablespace();
 337                 /* note InvalidOid is OK in this case */
 338         }
 339
 340         /* Check permissions except when using database's default */
 341         if (OidIsValid(tablespaceId))
 342         {
 343                 AclResult       aclresult;
 344
 345                 aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(),
 346                                                                                    ACL_CREATE);
 347                 if (aclresult != ACLCHECK_OK)
 348                         aclcheck_error(aclresult, ACL_KIND_TABLESPACE,
 349                                                    get_tablespace_name(tablespaceId));
 350         }
 351
 352         /*
 353          * Look up inheritance ancestors and generate relation schema, including
 354          * inherited attributes.
 355          */
 356         schema = MergeAttributes(schema, stmt->inhRelations,
 357                                                          stmt->relation->istemp,
 358                                                          &inheritOids, &old_constraints, &parentOidCount);
 359
 360         /*
 361          * Create a relation descriptor from the relation schema and create the
 362          * relation.  Note that in this stage only inherited (pre-cooked) defaults
 363          * and constraints will be included into the new relation.
 364          * (BuildDescForRelation takes care of the inherited defaults, but we have
 365          * to copy inherited constraints here.)
 366          */
 367         descriptor = BuildDescForRelation(schema);
 368
 369         localHasOids = interpretOidsOption(stmt->hasoids);
 370         descriptor->tdhasoid = (localHasOids || parentOidCount > 0);
 371
 372         if (old_constraints != NIL)
 373         {
 374                 ConstrCheck *check = (ConstrCheck *)
 375                 palloc0(list_length(old_constraints) * sizeof(ConstrCheck));
 376                 int                     ncheck = 0;
 377
 378                 foreach(listptr, old_constraints)
 379                 {
 380                         Constraint *cdef = (Constraint *) lfirst(listptr);
 381                         bool            dup = false;
 382
 383                         if (cdef->contype != CONSTR_CHECK)
 384                                 continue;
 385                         Assert(cdef->name != NULL);
 386                         Assert(cdef->raw_expr == NULL && cdef->cooked_expr != NULL);
 387
 388                         /*
 389                          * In multiple-inheritance situations, it's possible to inherit
 390                          * the same grandparent constraint through multiple parents.
 391                          * Hence, discard inherited constraints that match as to both name
 392                          * and expression.      Otherwise, gripe if the names conflict.
 393                          */
 394                         for (i = 0; i < ncheck; i++)
 395                         {
 396                                 if (strcmp(check[i].ccname, cdef->name) != 0)
 397                                         continue;
 398                                 if (strcmp(check[i].ccbin, cdef->cooked_expr) == 0)
 399                                 {
 400                                         dup = true;
 401                                         break;
 402                                 }
 403                                 ereport(ERROR,
 404                                                 (errcode(ERRCODE_DUPLICATE_OBJECT),
 405                                                  errmsg("duplicate check constraint name \"%s\"",
 406                                                                 cdef->name)));
 407                         }
 408                         if (!dup)
 409                         {
 410                                 check[ncheck].ccname = cdef->name;
 411                                 check[ncheck].ccbin = pstrdup(cdef->cooked_expr);
 412                                 ncheck++;
 413                         }
 414                 }
 415                 if (ncheck > 0)
 416                 {
 417                         if (descriptor->constr == NULL)
 418                         {
 419                                 descriptor->constr = (TupleConstr *) palloc(sizeof(TupleConstr));
 420                                 descriptor->constr->defval = NULL;
 421                                 descriptor->constr->num_defval = 0;
 422                                 descriptor->constr->has_not_null = false;
 423                         }
 424                         descriptor->constr->num_check = ncheck;
 425                         descriptor->constr->check = check;
 426                 }
 427         }
 428
 429         relationId = heap_create_with_catalog(relname,
 430                                                                                   namespaceId,
 431                                                                                   tablespaceId,
 432                                                                                   InvalidOid,
 433                                                                                   GetUserId(),
 434                                                                                   descriptor,
 435                                                                                   relkind,
 436                                                                                   false,
 437                                                                                   localHasOids,
 438                                                                                   parentOidCount,
 439                                                                                   stmt->oncommit,
 440                                                                                   allowSystemTableMods);
 441
 442         StoreCatalogInheritance(relationId, inheritOids);
 443
 444         /*
 445          * We must bump the command counter to make the newly-created relation
 446          * tuple visible for opening.
 447          */
 448         CommandCounterIncrement();
 449
 450         /*
 451          * Open the new relation and acquire exclusive lock on it.      This isn't
 452          * really necessary for locking out other backends (since they can't see
 453          * the new rel anyway until we commit), but it keeps the lock manager from
 454          * complaining about deadlock risks.
 455          */
 456         rel = relation_open(relationId, AccessExclusiveLock);
 457
 458         /*
 459          * Now add any newly specified column default values and CHECK constraints
 460          * to the new relation.  These are passed to us in the form of raw
 461          * parsetrees; we need to transform them to executable expression trees
 462          * before they can be added. The most convenient way to do that is to
 463          * apply the parser's transformExpr routine, but transformExpr doesn't
 464          * work unless we have a pre-existing relation. So, the transformation has
 465          * to be postponed to this final step of CREATE TABLE.
 466          *
 467          * Another task that's conveniently done at this step is to add dependency
 468          * links between columns and supporting relations (such as SERIAL
 469          * sequences).
 470          *
 471          * First, scan schema to find new column defaults.
 472          */
 473         rawDefaults = NIL;
 474         attnum = 0;
 475
 476         foreach(listptr, schema)
 477         {
 478                 ColumnDef  *colDef = lfirst(listptr);
 479
 480                 attnum++;
 481
 482                 if (colDef->raw_default != NULL)
 483                 {
 484                         RawColumnDefault *rawEnt;
 485
 486                         Assert(colDef->cooked_default == NULL);
 487
 488                         rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
 489                         rawEnt->attnum = attnum;
 490                         rawEnt->raw_default = colDef->raw_default;
 491                         rawDefaults = lappend(rawDefaults, rawEnt);
 492                 }
 493
 494                 /* Create dependency for supporting relation for this column */
 495                 if (colDef->support != NULL)
 496                         add_column_support_dependency(relationId, attnum, colDef->support);
 497         }
 498
 499         /*
 500          * Parse and add the defaults/constraints, if any.
 501          */
 502         if (rawDefaults || stmt->constraints)
 503                 AddRelationRawConstraints(rel, rawDefaults, stmt->constraints);
 504
 505         /*
 506          * Clean up.  We keep lock on new relation (although it shouldn't be
 507          * visible to anyone else anyway, until commit).
 508          */
 509         relation_close(rel, NoLock);
 510
 511         return relationId;
 512 }
 513
 514 /*
 515  * RemoveRelation
 516  *              Deletes a relation.
 517  */
 518 void
 519 RemoveRelation(const RangeVar *relation, DropBehavior behavior)
 520 {
 521         Oid                     relOid;
 522         ObjectAddress object;
 523
 524         relOid = RangeVarGetRelid(relation, false);
 525
 526         object.classId = RelationRelationId;
 527         object.objectId = relOid;
 528         object.objectSubId = 0;
 529
 530         performDeletion(&object, behavior);
 531 }
 532
 533 /*
 534  * ExecuteTruncate
 535  *              Executes a TRUNCATE command.
 536  *
 537  * This is a multi-relation truncate.  We first open and grab exclusive
 538  * lock on all relations involved, checking permissions and otherwise
 539  * verifying that the relation is OK for truncation.  In CASCADE mode,
 540  * relations having FK references to the targeted relations are automatically
 541  * added to the group; in RESTRICT mode, we check that all FK references are
 542  * internal to the group that's being truncated.  Finally all the relations
 543  * are truncated and reindexed.
 544  */
 545 void
 546 ExecuteTruncate(TruncateStmt *stmt)
 547 {
 548         List       *rels = NIL;
 549         List       *relids = NIL;
 550         ListCell   *cell;
 551
 552         /*
 553          * Open, exclusive-lock, and check all the explicitly-specified relations
 554          */
 555         foreach(cell, stmt->relations)
 556         {
 557                 RangeVar   *rv = lfirst(cell);
 558                 Relation        rel;
 559
 560                 rel = heap_openrv(rv, AccessExclusiveLock);
 561                 truncate_check_rel(rel);
 562                 rels = lappend(rels, rel);
 563                 relids = lappend_oid(relids, RelationGetRelid(rel));
 564         }
 565
 566         /*
 567          * In CASCADE mode, suck in all referencing relations as well.  This
 568          * requires multiple iterations to find indirectly-dependent relations.
 569          * At each phase, we need to exclusive-lock new rels before looking
 570          * for their dependencies, else we might miss something.  Also, we
 571          * check each rel as soon as we open it, to avoid a faux pas such as
 572          * holding lock for a long time on a rel we have no permissions for.
 573          */
 574         if (stmt->behavior == DROP_CASCADE)
 575         {
 576                 for (;;)
 577                 {
 578                         List   *newrelids;
 579
 580                         newrelids = heap_truncate_find_FKs(relids);
 581                         if (newrelids == NIL)
 582                                 break;                  /* nothing else to add */
 583
 584                         foreach(cell, newrelids)
 585                         {
 586                                 Oid             relid = lfirst_oid(cell);
 587                                 Relation        rel;
 588
 589                                 rel = heap_open(relid, AccessExclusiveLock);
 590                                 ereport(NOTICE,
 591                                                 (errmsg("truncate cascades to table \"%s\"",
 592                                                                 RelationGetRelationName(rel))));
 593                                 truncate_check_rel(rel);
 594                                 rels = lappend(rels, rel);
 595                                 relids = lappend_oid(relids, relid);
 596                         }
 597                 }
 598         }
 599
 600         /*
 601          * Check foreign key references.  In CASCADE mode, this should be
 602          * unnecessary since we just pulled in all the references; but as
 603          * a cross-check, do it anyway if in an Assert-enabled build.
 604          */
 605 #ifdef USE_ASSERT_CHECKING
 606         heap_truncate_check_FKs(rels, false);
 607 #else
 608         if (stmt->behavior == DROP_RESTRICT)
 609                 heap_truncate_check_FKs(rels, false);
 610 #endif
 611
 612         /*
 613          * OK, truncate each table.
 614          */
 615         foreach(cell, rels)
 616         {
 617                 Relation        rel = (Relation) lfirst(cell);
 618                 Oid                     heap_relid;
 619                 Oid                     toast_relid;
 620
 621                 /*
 622                  * Create a new empty storage file for the relation, and assign it as
 623                  * the relfilenode value.       The old storage file is scheduled for
 624                  * deletion at commit.
 625                  */
 626                 setNewRelfilenode(rel);
 627
 628                 heap_relid = RelationGetRelid(rel);
 629                 toast_relid = rel->rd_rel->reltoastrelid;
 630
 631                 heap_close(rel, NoLock);
 632
 633                 /*
 634                  * The same for the toast table, if any.
 635                  */
 636                 if (OidIsValid(toast_relid))
 637                 {
 638                         rel = relation_open(toast_relid, AccessExclusiveLock);
 639                         setNewRelfilenode(rel);
 640                         heap_close(rel, NoLock);
 641                 }
 642
 643                 /*
 644                  * Reconstruct the indexes to match, and we're done.
 645                  */
 646                 reindex_relation(heap_relid, true);
 647         }
 648 }
 649
 650 /*
 651  * Check that a given rel is safe to truncate.  Subroutine for ExecuteTruncate
 652  */
 653 static void
 654 truncate_check_rel(Relation rel)
 655 {
 656         /* Only allow truncate on regular tables */
 657         if (rel->rd_rel->relkind != RELKIND_RELATION)
 658                 ereport(ERROR,
 659                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 660                                  errmsg("\"%s\" is not a table",
 661                                                 RelationGetRelationName(rel))));
 662
 663         /* Permissions checks */
 664         if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
 665                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
 666                                            RelationGetRelationName(rel));
 667
 668         if (!allowSystemTableMods && IsSystemRelation(rel))
 669                 ereport(ERROR,
 670                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 671                                  errmsg("permission denied: \"%s\" is a system catalog",
 672                                                 RelationGetRelationName(rel))));
 673
 674         /*
 675          * We can never allow truncation of shared or nailed-in-cache
 676          * relations, because we can't support changing their relfilenode
 677          * values.
 678          */
 679         if (rel->rd_rel->relisshared || rel->rd_isnailed)
 680                 ereport(ERROR,
 681                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 682                                  errmsg("cannot truncate system relation \"%s\"",
 683                                                 RelationGetRelationName(rel))));
 684
 685         /*
 686          * Don't allow truncate on temp tables of other backends ... their
 687          * local buffer manager is not going to cope.
 688          */
 689         if (isOtherTempNamespace(RelationGetNamespace(rel)))
 690                 ereport(ERROR,
 691                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 692                                  errmsg("cannot truncate temporary tables of other sessions")));
 693 }
 694
 695 /*----------
 696  * MergeAttributes
 697  *              Returns new schema given initial schema and superclasses.
 698  *
 699  * Input arguments:
 700  * 'schema' is the column/attribute definition for the table. (It's a list
 701  *              of ColumnDef's.) It is destructively changed.
 702  * 'supers' is a list of names (as RangeVar nodes) of parent relations.
 703  * 'istemp' is TRUE if we are creating a temp relation.
 704  *
 705  * Output arguments:
 706  * 'supOids' receives a list of the OIDs of the parent relations.
 707  * 'supconstr' receives a list of constraints belonging to the parents,
 708  *              updated as necessary to be valid for the child.
 709  * 'supOidCount' is set to the number of parents that have OID columns.
 710  *
 711  * Return value:
 712  * Completed schema list.
 713  *
 714  * Notes:
 715  *        The order in which the attributes are inherited is very important.
 716  *        Intuitively, the inherited attributes should come first. If a table
 717  *        inherits from multiple parents, the order of those attributes are
 718  *        according to the order of the parents specified in CREATE TABLE.
 719  *
 720  *        Here's an example:
 721  *
 722  *              create table person (name text, age int4, location point);
 723  *              create table emp (salary int4, manager text) inherits(person);
 724  *              create table student (gpa float8) inherits (person);
 725  *              create table stud_emp (percent int4) inherits (emp, student);
 726  *
 727  *        The order of the attributes of stud_emp is:
 728  *
 729  *                                                      person {1:name, 2:age, 3:location}
 730  *                                                      /        \
 731  *                         {6:gpa}      student   emp {4:salary, 5:manager}
 732  *                                                      \        /
 733  *                                                 stud_emp {7:percent}
 734  *
 735  *         If the same attribute name appears multiple times, then it appears
 736  *         in the result table in the proper location for its first appearance.
 737  *
 738  *         Constraints (including NOT NULL constraints) for the child table
 739  *         are the union of all relevant constraints, from both the child schema
 740  *         and parent tables.
 741  *
 742  *         The default value for a child column is defined as:
 743  *              (1) If the child schema specifies a default, that value is used.
 744  *              (2) If neither the child nor any parent specifies a default, then
 745  *                      the column will not have a default.
 746  *              (3) If conflicting defaults are inherited from different parents
 747  *                      (and not overridden by the child), an error is raised.
 748  *              (4) Otherwise the inherited default is used.
 749  *              Rule (3) is new in Postgres 7.1; in earlier releases you got a
 750  *              rather arbitrary choice of which parent default to use.
 751  *----------
 752  */
 753 static List *
 754 MergeAttributes(List *schema, List *supers, bool istemp,
 755                                 List **supOids, List **supconstr, int *supOidCount)
 756 {
 757         ListCell   *entry;
 758         List       *inhSchema = NIL;
 759         List       *parentOids = NIL;
 760         List       *constraints = NIL;
 761         int                     parentsWithOids = 0;
 762         bool            have_bogus_defaults = false;
 763         char       *bogus_marker = "Bogus!";            /* marks conflicting defaults */
 764         int                     child_attno;
 765
 766         /*
 767          * Check for and reject tables with too many columns. We perform this
 768          * check relatively early for two reasons: (a) we don't run the risk of
 769          * overflowing an AttrNumber in subsequent code (b) an O(n^2) algorithm is
 770          * okay if we're processing <= 1600 columns, but could take minutes to
 771          * execute if the user attempts to create a table with hundreds of
 772          * thousands of columns.
 773          *
 774          * Note that we also need to check that any we do not exceed this figure
 775          * after including columns from inherited relations.
 776          */
 777         if (list_length(schema) > MaxHeapAttributeNumber)
 778                 ereport(ERROR,
 779                                 (errcode(ERRCODE_TOO_MANY_COLUMNS),
 780                                  errmsg("tables can have at most %d columns",
 781                                                 MaxHeapAttributeNumber)));
 782
 783         /*
 784          * Check for duplicate names in the explicit list of attributes.
 785          *
 786          * Although we might consider merging such entries in the same way that we
 787          * handle name conflicts for inherited attributes, it seems to make more
 788          * sense to assume such conflicts are errors.
 789          */
 790         foreach(entry, schema)
 791         {
 792                 ColumnDef  *coldef = lfirst(entry);
 793                 ListCell   *rest;
 794
 795                 for_each_cell(rest, lnext(entry))
 796                 {
 797                         ColumnDef  *restdef = lfirst(rest);
 798
 799                         if (strcmp(coldef->colname, restdef->colname) == 0)
 800                                 ereport(ERROR,
 801                                                 (errcode(ERRCODE_DUPLICATE_COLUMN),
 802                                                  errmsg("column \"%s\" duplicated",
 803                                                                 coldef->colname)));
 804                 }
 805         }
 806
 807         /*
 808          * Scan the parents left-to-right, and merge their attributes to form a
 809          * list of inherited attributes (inhSchema).  Also check to see if we need
 810          * to inherit an OID column.
 811          */
 812         child_attno = 0;
 813         foreach(entry, supers)
 814         {
 815                 RangeVar   *parent = (RangeVar *) lfirst(entry);
 816                 Relation        relation;
 817                 TupleDesc       tupleDesc;
 818                 TupleConstr *constr;
 819                 AttrNumber *newattno;
 820                 AttrNumber      parent_attno;
 821
 822                 relation = heap_openrv(parent, AccessShareLock);
 823
 824                 if (relation->rd_rel->relkind != RELKIND_RELATION)
 825                         ereport(ERROR,
 826                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 827                                          errmsg("inherited relation \"%s\" is not a table",
 828                                                         parent->relname)));
 829                 /* Permanent rels cannot inherit from temporary ones */
 830                 if (!istemp && isTempNamespace(RelationGetNamespace(relation)))
 831                         ereport(ERROR,
 832                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 833                                          errmsg("cannot inherit from temporary relation \"%s\"",
 834                                                         parent->relname)));
 835
 836                 /*
 837                  * We should have an UNDER permission flag for this, but for now,
 838                  * demand that creator of a child table own the parent.
 839                  */
 840                 if (!pg_class_ownercheck(RelationGetRelid(relation), GetUserId()))
 841                         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
 842                                                    RelationGetRelationName(relation));
 843
 844                 /*
 845                  * Reject duplications in the list of parents.
 846                  */
 847                 if (list_member_oid(parentOids, RelationGetRelid(relation)))
 848                         ereport(ERROR,
 849                                         (errcode(ERRCODE_DUPLICATE_TABLE),
 850                                          errmsg("inherited relation \"%s\" duplicated",
 851                                                         parent->relname)));
 852
 853                 parentOids = lappend_oid(parentOids, RelationGetRelid(relation));
 854
 855                 if (relation->rd_rel->relhasoids)
 856                         parentsWithOids++;
 857
 858                 tupleDesc = RelationGetDescr(relation);
 859                 constr = tupleDesc->constr;
 860
 861                 /*
 862                  * newattno[] will contain the child-table attribute numbers for the
 863                  * attributes of this parent table.  (They are not the same for
 864                  * parents after the first one, nor if we have dropped columns.)
 865                  */
 866                 newattno = (AttrNumber *)
 867                         palloc(tupleDesc->natts * sizeof(AttrNumber));
 868
 869                 for (parent_attno = 1; parent_attno <= tupleDesc->natts;
 870                          parent_attno++)
 871                 {
 872                         Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1];
 873                         char       *attributeName = NameStr(attribute->attname);
 874                         int                     exist_attno;
 875                         ColumnDef  *def;
 876
 877                         /*
 878                          * Ignore dropped columns in the parent.
 879                          */
 880                         if (attribute->attisdropped)
 881                         {
 882                                 /*
 883                                  * change_varattnos_of_a_node asserts that this is greater
 884                                  * than zero, so if anything tries to use it, we should find
 885                                  * out.
 886                                  */
 887                                 newattno[parent_attno - 1] = 0;
 888                                 continue;
 889                         }
 890
 891                         /*
 892                          * Does it conflict with some previously inherited column?
 893                          */
 894                         exist_attno = findAttrByName(attributeName, inhSchema);
 895                         if (exist_attno > 0)
 896                         {
 897                                 /*
 898                                  * Yes, try to merge the two column definitions. They must
 899                                  * have the same type and typmod.
 900                                  */
 901                                 ereport(NOTICE,
 902                                                 (errmsg("merging multiple inherited definitions of column \"%s\"",
 903                                                                 attributeName)));
 904                                 def = (ColumnDef *) list_nth(inhSchema, exist_attno - 1);
 905                                 if (typenameTypeId(NULL, def->typename) != attribute->atttypid ||
 906                                         def->typename->typmod != attribute->atttypmod)
 907                                         ereport(ERROR,
 908                                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
 909                                                 errmsg("inherited column \"%s\" has a type conflict",
 910                                                            attributeName),
 911                                                          errdetail("%s versus %s",
 912                                                                            TypeNameToString(def->typename),
 913                                                                            format_type_be(attribute->atttypid))));
 914                                 def->inhcount++;
 915                                 /* Merge of NOT NULL constraints = OR 'em together */
 916                                 def->is_not_null |= attribute->attnotnull;
 917                                 /* Default and other constraints are handled below */
 918                                 newattno[parent_attno - 1] = exist_attno;
 919                         }
 920                         else
 921                         {
 922                                 /*
 923                                  * No, create a new inherited column
 924                                  */
 925                                 def = makeNode(ColumnDef);
 926                                 def->colname = pstrdup(attributeName);
 927                                 def->typename = makeTypeNameFromOid(attribute->atttypid,
 928                                                                                                         attribute->atttypmod);
 929                                 def->inhcount = 1;
 930                                 def->is_local = false;
 931                                 def->is_not_null = attribute->attnotnull;
 932                                 def->raw_default = NULL;
 933                                 def->cooked_default = NULL;
 934                                 def->constraints = NIL;
 935                                 def->support = NULL;
 936                                 inhSchema = lappend(inhSchema, def);
 937                                 newattno[parent_attno - 1] = ++child_attno;
 938                         }
 939
 940                         /*
 941                          * Copy default if any
 942                          */
 943                         if (attribute->atthasdef)
 944                         {
 945                                 char       *this_default = NULL;
 946                                 AttrDefault *attrdef;
 947                                 int                     i;
 948
 949                                 /* Find default in constraint structure */
 950                                 Assert(constr != NULL);
 951                                 attrdef = constr->defval;
 952                                 for (i = 0; i < constr->num_defval; i++)
 953                                 {
 954                                         if (attrdef[i].adnum == parent_attno)
 955                                         {
 956                                                 this_default = attrdef[i].adbin;
 957                                                 break;
 958                                         }
 959                                 }
 960                                 Assert(this_default != NULL);
 961
 962                                 /*
 963                                  * If default expr could contain any vars, we'd need to fix
 964                                  * 'em, but it can't; so default is ready to apply to child.
 965                                  *
 966                                  * If we already had a default from some prior parent, check
 967                                  * to see if they are the same.  If so, no problem; if not,
 968                                  * mark the column as having a bogus default. Below, we will
 969                                  * complain if the bogus default isn't overridden by the child
 970                                  * schema.
 971                                  */
 972                                 Assert(def->raw_default == NULL);
 973                                 if (def->cooked_default == NULL)
 974                                         def->cooked_default = pstrdup(this_default);
 975                                 else if (strcmp(def->cooked_default, this_default) != 0)
 976                                 {
 977                                         def->cooked_default = bogus_marker;
 978                                         have_bogus_defaults = true;
 979                                 }
 980                         }
 981                 }
 982
 983                 /*
 984                  * Now copy the constraints of this parent, adjusting attnos using the
 985                  * completed newattno[] map
 986                  */
 987                 if (constr && constr->num_check > 0)
 988                 {
 989                         ConstrCheck *check = constr->check;
 990                         int                     i;
 991
 992                         for (i = 0; i < constr->num_check; i++)
 993                         {
 994                                 Constraint *cdef = makeNode(Constraint);
 995                                 Node       *expr;
 996
 997                                 cdef->contype = CONSTR_CHECK;
 998                                 cdef->name = pstrdup(check[i].ccname);
 999                                 cdef->raw_expr = NULL;
1000                                 /* adjust varattnos of ccbin here */
1001                                 expr = stringToNode(check[i].ccbin);
1002                                 change_varattnos_of_a_node(expr, newattno);
1003                                 cdef->cooked_expr = nodeToString(expr);
1004                                 constraints = lappend(constraints, cdef);
1005                         }
1006                 }
1007
1008                 pfree(newattno);
1009
1010                 /*
1011                  * Close the parent rel, but keep our AccessShareLock on it until xact
1012                  * commit.      That will prevent someone else from deleting or ALTERing
1013                  * the parent before the child is committed.
1014                  */
1015                 heap_close(relation, NoLock);
1016         }
1017
1018         /*
1019          * If we had no inherited attributes, the result schema is just the
1020          * explicitly declared columns.  Otherwise, we need to merge the declared
1021          * columns into the inherited schema list.
1022          */
1023         if (inhSchema != NIL)
1024         {
1025                 foreach(entry, schema)
1026                 {
1027                         ColumnDef  *newdef = lfirst(entry);
1028                         char       *attributeName = newdef->colname;
1029                         int                     exist_attno;
1030
1031                         /*
1032                          * Does it conflict with some previously inherited column?
1033                          */
1034                         exist_attno = findAttrByName(attributeName, inhSchema);
1035                         if (exist_attno > 0)
1036                         {
1037                                 ColumnDef  *def;
1038
1039                                 /*
1040                                  * Yes, try to merge the two column definitions. They must
1041                                  * have the same type and typmod.
1042                                  */
1043                                 ereport(NOTICE,
1044                                    (errmsg("merging column \"%s\" with inherited definition",
1045                                                    attributeName)));
1046                                 def = (ColumnDef *) list_nth(inhSchema, exist_attno - 1);
1047                                 if (typenameTypeId(NULL, def->typename) != typenameTypeId(NULL, newdef->typename) ||
1048                                         def->typename->typmod != newdef->typename->typmod)
1049                                         ereport(ERROR,
1050                                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
1051                                                          errmsg("column \"%s\" has a type conflict",
1052                                                                         attributeName),
1053                                                          errdetail("%s versus %s",
1054                                                                            TypeNameToString(def->typename),
1055                                                                            TypeNameToString(newdef->typename))));
1056                                 /* Mark the column as locally defined */
1057                                 def->is_local = true;
1058                                 /* Merge of NOT NULL constraints = OR 'em together */
1059                                 def->is_not_null |= newdef->is_not_null;
1060                                 /* If new def has a default, override previous default */
1061                                 if (newdef->raw_default != NULL)
1062                                 {
1063                                         def->raw_default = newdef->raw_default;
1064                                         def->cooked_default = newdef->cooked_default;
1065                                 }
1066                         }
1067                         else
1068                         {
1069                                 /*
1070                                  * No, attach new column to result schema
1071                                  */
1072                                 inhSchema = lappend(inhSchema, newdef);
1073                         }
1074                 }
1075
1076                 schema = inhSchema;
1077
1078                 /*
1079                  * Check that we haven't exceeded the legal # of columns after merging
1080                  * in inherited columns.
1081                  */
1082                 if (list_length(schema) > MaxHeapAttributeNumber)
1083                         ereport(ERROR,
1084                                         (errcode(ERRCODE_TOO_MANY_COLUMNS),
1085                                          errmsg("tables can have at most %d columns",
1086                                                         MaxHeapAttributeNumber)));
1087         }
1088
1089         /*
1090          * If we found any conflicting parent default values, check to make sure
1091          * they were overridden by the child.
1092          */
1093         if (have_bogus_defaults)
1094         {
1095                 foreach(entry, schema)
1096                 {
1097                         ColumnDef  *def = lfirst(entry);
1098
1099                         if (def->cooked_default == bogus_marker)
1100                                 ereport(ERROR,
1101                                                 (errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
1102                                   errmsg("column \"%s\" inherits conflicting default values",
1103                                                  def->colname),
1104                                                  errhint("To resolve the conflict, specify a default explicitly.")));
1105                 }
1106         }
1107
1108         *supOids = parentOids;
1109         *supconstr = constraints;
1110         *supOidCount = parentsWithOids;
1111         return schema;
1112 }
1113
1114 /*
1115  * Varattnos of pg_constraint.conbin must be rewritten when subclasses inherit
1116  * constraints from parent classes, since the inherited attributes could
1117  * be given different column numbers in multiple-inheritance cases.
1118  *
1119  * Note that the passed node tree is modified in place!
1120  *
1121  * This function is used elsewhere such as in analyze.c
1122  *
1123  */
1124
1125 void
1126 change_varattnos_of_a_node(Node *node, const AttrNumber *newattno)
1127 {
1128         change_varattnos_walker(node, newattno);
1129 }
1130
1131 /* Generate a map for change_varattnos_of_a_node from two tupledesc's. */
1132
1133 AttrNumber *
1134 varattnos_map(TupleDesc old, TupleDesc new)
1135 {
1136         int i,j;
1137         AttrNumber *attmap = palloc0(sizeof(AttrNumber)*old->natts);
1138         for (i=1; i <= old->natts; i++) {
1139                 if (old->attrs[i-1]->attisdropped) {
1140                         attmap[i-1] = 0;
1141                         continue;
1142                 }
1143                 for (j=1; j<= new->natts; j++)
1144                         if (!strcmp(NameStr(old->attrs[i-1]->attname), NameStr(new->attrs[j-1]->attname)))
1145                                 attmap[i-1] = j;
1146         }
1147         return attmap;
1148 }
1149
1150 /* Generate a map for change_varattnos_of_a_node from a tupledesc and a list of
1151  * ColumnDefs */
1152
1153 AttrNumber *
1154 varattnos_map_schema(TupleDesc old, List *schema)
1155 {
1156         int i;
1157         AttrNumber *attmap = palloc0(sizeof(AttrNumber)*old->natts);
1158         for (i=1; i <= old->natts; i++) {
1159                 if (old->attrs[i-1]->attisdropped) {
1160                         attmap[i-1] = 0;
1161                         continue;
1162                 }
1163                 attmap[i-1] = findAttrByName(NameStr(old->attrs[i-1]->attname), schema);
1164         }
1165         return attmap;
1166 }
1167
1168 static bool
1169 change_varattnos_walker(Node *node, const AttrNumber *newattno)
1170 {
1171         if (node == NULL)
1172                 return false;
1173         if (IsA(node, Var))
1174         {
1175                 Var                *var = (Var *) node;
1176
1177                 if (var->varlevelsup == 0 && var->varno == 1 &&
1178                         var->varattno > 0)
1179                 {
1180                         /*
1181                          * ??? the following may be a problem when the node is multiply
1182                          * referenced though stringToNode() doesn't create such a node
1183                          * currently.
1184                          */
1185                         Assert(newattno[var->varattno - 1] > 0);
1186                         var->varattno = newattno[var->varattno - 1];
1187                 }
1188                 return false;
1189         }
1190         return expression_tree_walker(node, change_varattnos_walker,
1191                                                                   (void *) newattno);
1192 }
1193
1194 /*
1195  * StoreCatalogInheritance
1196  *              Updates the system catalogs with proper inheritance information.
1197  *
1198  * supers is a list of the OIDs of the new relation's direct ancestors.
1199  */
1200 static void
1201 StoreCatalogInheritance(Oid relationId, List *supers)
1202 {
1203         Relation        relation;
1204         int16           seqNumber;
1205         ListCell   *entry;
1206
1207         /*
1208          * sanity checks
1209          */
1210         AssertArg(OidIsValid(relationId));
1211
1212         if (supers == NIL)
1213                 return;
1214
1215         /*
1216          * Store INHERITS information in pg_inherits using direct ancestors only.
1217          * Also enter dependencies on the direct ancestors, and make sure they are
1218          * marked with relhassubclass = true.
1219          *
1220          * (Once upon a time, both direct and indirect ancestors were found here
1221          * and then entered into pg_ipl.  Since that catalog doesn't exist
1222          * anymore, there's no need to look for indirect ancestors.)
1223          */
1224         relation = heap_open(InheritsRelationId, RowExclusiveLock);
1225
1226         seqNumber = 1;
1227         foreach(entry, supers)
1228         {
1229                 StoreCatalogInheritance1(relationId, lfirst_oid(entry), seqNumber, relation);
1230                 seqNumber += 1;
1231         }
1232
1233         heap_close(relation, RowExclusiveLock);
1234 }
1235
1236 static void
1237 StoreCatalogInheritance1(Oid relationId, Oid parentOid, int16 seqNumber, Relation relation)
1238 {
1239                 Datum           datum[Natts_pg_inherits];
1240                 char            nullarr[Natts_pg_inherits];
1241                 ObjectAddress childobject,
1242                                         parentobject;
1243                 HeapTuple       tuple;
1244                 TupleDesc desc = RelationGetDescr(relation);
1245
1246                 datum[0] = ObjectIdGetDatum(relationId);                /* inhrel */
1247                 datum[1] = ObjectIdGetDatum(parentOid); /* inhparent */
1248                 datum[2] = Int16GetDatum(seqNumber);    /* inhseqno */
1249
1250                 nullarr[0] = ' ';
1251                 nullarr[1] = ' ';
1252                 nullarr[2] = ' ';
1253
1254                 tuple = heap_formtuple(desc, datum, nullarr);
1255
1256                 simple_heap_insert(relation, tuple);
1257
1258                 CatalogUpdateIndexes(relation, tuple);
1259
1260                 heap_freetuple(tuple);
1261
1262                 /*
1263                  * Store a dependency too
1264                  */
1265                 parentobject.classId = RelationRelationId;
1266                 parentobject.objectId = parentOid;
1267                 parentobject.objectSubId = 0;
1268                 childobject.classId = RelationRelationId;
1269                 childobject.objectId = relationId;
1270                 childobject.objectSubId = 0;
1271
1272                 recordDependencyOn(&childobject, &parentobject, DEPENDENCY_NORMAL);
1273
1274                 /*
1275                  * Mark the parent as having subclasses.
1276                  */
1277                 setRelhassubclassInRelation(parentOid, true);
1278
1279 }
1280
1281 /*
1282  * Look for an existing schema entry with the given name.
1283  *
1284  * Returns the index (starting with 1) if attribute already exists in schema,
1285  * 0 if it doesn't.
1286  */
1287 static int
1288 findAttrByName(const char *attributeName, List *schema)
1289 {
1290         ListCell   *s;
1291         int                     i = 1;
1292
1293         foreach(s, schema)
1294         {
1295                 ColumnDef  *def = lfirst(s);
1296
1297                 if (strcmp(attributeName, def->colname) == 0)
1298                         return i;
1299
1300                 i++;
1301         }
1302         return 0;
1303 }
1304
1305 /*
1306  * Update a relation's pg_class.relhassubclass entry to the given value
1307  */
1308 static void
1309 setRelhassubclassInRelation(Oid relationId, bool relhassubclass)
1310 {
1311         Relation        relationRelation;
1312         HeapTuple       tuple;
1313         Form_pg_class classtuple;
1314
1315         /*
1316          * Fetch a modifiable copy of the tuple, modify it, update pg_class.
1317          *
1318          * If the tuple already has the right relhassubclass setting, we don't
1319          * need to update it, but we still need to issue an SI inval message.
1320          */
1321         relationRelation = heap_open(RelationRelationId, RowExclusiveLock);
1322         tuple = SearchSysCacheCopy(RELOID,
1323                                                            ObjectIdGetDatum(relationId),
1324                                                            0, 0, 0);
1325         if (!HeapTupleIsValid(tuple))
1326                 elog(ERROR, "cache lookup failed for relation %u", relationId);
1327         classtuple = (Form_pg_class) GETSTRUCT(tuple);
1328
1329         if (classtuple->relhassubclass != relhassubclass)
1330         {
1331                 classtuple->relhassubclass = relhassubclass;
1332                 simple_heap_update(relationRelation, &tuple->t_self, tuple);
1333
1334                 /* keep the catalog indexes up to date */
1335                 CatalogUpdateIndexes(relationRelation, tuple);
1336         }
1337         else
1338         {
1339                 /* no need to change tuple, but force relcache rebuild anyway */
1340                 CacheInvalidateRelcacheByTuple(tuple);
1341         }
1342
1343         heap_freetuple(tuple);
1344         heap_close(relationRelation, RowExclusiveLock);
1345 }
1346
1347
1348 /*
1349  *              renameatt               - changes the name of a attribute in a relation
1350  *
1351  *              Attname attribute is changed in attribute catalog.
1352  *              No record of the previous attname is kept (correct?).
1353  *
1354  *              get proper relrelation from relation catalog (if not arg)
1355  *              scan attribute catalog
1356  *                              for name conflict (within rel)
1357  *                              for original attribute (if not arg)
1358  *              modify attname in attribute tuple
1359  *              insert modified attribute in attribute catalog
1360  *              delete original attribute from attribute catalog
1361  */
1362 void
1363 renameatt(Oid myrelid,
1364                   const char *oldattname,
1365                   const char *newattname,
1366                   bool recurse,
1367                   bool recursing)
1368 {
1369         Relation        targetrelation;
1370         Relation        attrelation;
1371         HeapTuple       atttup;
1372         Form_pg_attribute attform;
1373         int                     attnum;
1374         List       *indexoidlist;
1375         ListCell   *indexoidscan;
1376
1377         /*
1378          * Grab an exclusive lock on the target table, which we will NOT release
1379          * until end of transaction.
1380          */
1381         targetrelation = relation_open(myrelid, AccessExclusiveLock);
1382
1383         /*
1384          * permissions checking.  this would normally be done in utility.c, but
1385          * this particular routine is recursive.
1386          *
1387          * normally, only the owner of a class can change its schema.
1388          */
1389         if (!pg_class_ownercheck(myrelid, GetUserId()))
1390                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
1391                                            RelationGetRelationName(targetrelation));
1392         if (!allowSystemTableMods && IsSystemRelation(targetrelation))
1393                 ereport(ERROR,
1394                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
1395                                  errmsg("permission denied: \"%s\" is a system catalog",
1396                                                 RelationGetRelationName(targetrelation))));
1397
1398         /*
1399          * if the 'recurse' flag is set then we are supposed to rename this
1400          * attribute in all classes that inherit from 'relname' (as well as in
1401          * 'relname').
1402          *
1403          * any permissions or problems with duplicate attributes will cause the
1404          * whole transaction to abort, which is what we want -- all or nothing.
1405          */
1406         if (recurse)
1407         {
1408                 ListCell   *child;
1409                 List       *children;
1410
1411                 /* this routine is actually in the planner */
1412                 children = find_all_inheritors(myrelid);
1413
1414                 /*
1415                  * find_all_inheritors does the recursive search of the inheritance
1416                  * hierarchy, so all we have to do is process all of the relids in the
1417                  * list that it returns.
1418                  */
1419                 foreach(child, children)
1420                 {
1421                         Oid                     childrelid = lfirst_oid(child);
1422
1423                         if (childrelid == myrelid)
1424                                 continue;
1425                         /* note we need not recurse again */
1426                         renameatt(childrelid, oldattname, newattname, false, true);
1427                 }
1428         }
1429         else
1430         {
1431                 /*
1432                  * If we are told not to recurse, there had better not be any child
1433                  * tables; else the rename would put them out of step.
1434                  */
1435                 if (!recursing &&
1436                         find_inheritance_children(myrelid) != NIL)
1437                         ereport(ERROR,
1438                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
1439                                          errmsg("inherited column \"%s\" must be renamed in child tables too",
1440                                                         oldattname)));
1441         }
1442
1443         attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
1444
1445         atttup = SearchSysCacheCopyAttName(myrelid, oldattname);
1446         if (!HeapTupleIsValid(atttup))
1447                 ereport(ERROR,
1448                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
1449                                  errmsg("column \"%s\" does not exist",
1450                                                 oldattname)));
1451         attform = (Form_pg_attribute) GETSTRUCT(atttup);
1452
1453         attnum = attform->attnum;
1454         if (attnum <= 0)
1455                 ereport(ERROR,
1456                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1457                                  errmsg("cannot rename system column \"%s\"",
1458                                                 oldattname)));
1459
1460         /*
1461          * if the attribute is inherited, forbid the renaming, unless we are
1462          * already inside a recursive rename.
1463          */
1464         if (attform->attinhcount > 0 && !recursing)
1465                 ereport(ERROR,
1466                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
1467                                  errmsg("cannot rename inherited column \"%s\"",
1468                                                 oldattname)));
1469
1470         /* should not already exist */
1471         /* this test is deliberately not attisdropped-aware */
1472         if (SearchSysCacheExists(ATTNAME,
1473                                                          ObjectIdGetDatum(myrelid),
1474                                                          PointerGetDatum(newattname),
1475                                                          0, 0))
1476                 ereport(ERROR,
1477                                 (errcode(ERRCODE_DUPLICATE_COLUMN),
1478                                  errmsg("column \"%s\" of relation \"%s\" already exists",
1479                                           newattname, RelationGetRelationName(targetrelation))));
1480
1481         namestrcpy(&(attform->attname), newattname);
1482
1483         simple_heap_update(attrelation, &atttup->t_self, atttup);
1484
1485         /* keep system catalog indexes current */
1486         CatalogUpdateIndexes(attrelation, atttup);
1487
1488         heap_freetuple(atttup);
1489
1490         /*
1491          * Update column names of indexes that refer to the column being renamed.
1492          */
1493         indexoidlist = RelationGetIndexList(targetrelation);
1494
1495         foreach(indexoidscan, indexoidlist)
1496         {
1497                 Oid                     indexoid = lfirst_oid(indexoidscan);
1498                 HeapTuple       indextup;
1499                 Form_pg_index indexform;
1500                 int                     i;
1501
1502                 /*
1503                  * Scan through index columns to see if there's any simple index
1504                  * entries for this attribute.  We ignore expressional entries.
1505                  */
1506                 indextup = SearchSysCache(INDEXRELID,
1507                                                                   ObjectIdGetDatum(indexoid),
1508                                                                   0, 0, 0);
1509                 if (!HeapTupleIsValid(indextup))
1510                         elog(ERROR, "cache lookup failed for index %u", indexoid);
1511                 indexform = (Form_pg_index) GETSTRUCT(indextup);
1512
1513                 for (i = 0; i < indexform->indnatts; i++)
1514                 {
1515                         if (attnum != indexform->indkey.values[i])
1516                                 continue;
1517
1518                         /*
1519                          * Found one, rename it.
1520                          */
1521                         atttup = SearchSysCacheCopy(ATTNUM,
1522                                                                                 ObjectIdGetDatum(indexoid),
1523                                                                                 Int16GetDatum(i + 1),
1524                                                                                 0, 0);
1525                         if (!HeapTupleIsValid(atttup))
1526                                 continue;               /* should we raise an error? */
1527
1528                         /*
1529                          * Update the (copied) attribute tuple.
1530                          */
1531                         namestrcpy(&(((Form_pg_attribute) GETSTRUCT(atttup))->attname),
1532                                            newattname);
1533
1534                         simple_heap_update(attrelation, &atttup->t_self, atttup);
1535
1536                         /* keep system catalog indexes current */
1537                         CatalogUpdateIndexes(attrelation, atttup);
1538
1539                         heap_freetuple(atttup);
1540                 }
1541
1542                 ReleaseSysCache(indextup);
1543         }
1544
1545         list_free(indexoidlist);
1546
1547         heap_close(attrelation, RowExclusiveLock);
1548
1549         /*
1550          * Update att name in any RI triggers associated with the relation.
1551          */
1552         if (targetrelation->rd_rel->reltriggers > 0)
1553         {
1554                 /* update tgargs column reference where att is primary key */
1555                 update_ri_trigger_args(RelationGetRelid(targetrelation),
1556                                                            oldattname, newattname,
1557                                                            false, false);
1558                 /* update tgargs column reference where att is foreign key */
1559                 update_ri_trigger_args(RelationGetRelid(targetrelation),
1560                                                            oldattname, newattname,
1561                                                            true, false);
1562         }
1563
1564         relation_close(targetrelation, NoLock);         /* close rel but keep lock */
1565 }
1566
1567 /*
1568  *              renamerel               - change the name of a relation
1569  *
1570  *              XXX - When renaming sequences, we don't bother to modify the
1571  *                        sequence name that is stored within the sequence itself
1572  *                        (this would cause problems with MVCC). In the future,
1573  *                        the sequence name should probably be removed from the
1574  *                        sequence, AFAIK there's no need for it to be there.
1575  */
1576 void
1577 renamerel(Oid myrelid, const char *newrelname)
1578 {
1579         Relation        targetrelation;
1580         Relation        relrelation;    /* for RELATION relation */
1581         HeapTuple       reltup;
1582         Oid                     namespaceId;
1583         char       *oldrelname;
1584         char            relkind;
1585         bool            relhastriggers;
1586
1587         /*
1588          * Grab an exclusive lock on the target table or index, which we will NOT
1589          * release until end of transaction.
1590          */
1591         targetrelation = relation_open(myrelid, AccessExclusiveLock);
1592
1593         oldrelname = pstrdup(RelationGetRelationName(targetrelation));
1594         namespaceId = RelationGetNamespace(targetrelation);
1595
1596         if (!allowSystemTableMods && IsSystemRelation(targetrelation))
1597                 ereport(ERROR,
1598                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
1599                                  errmsg("permission denied: \"%s\" is a system catalog",
1600                                                 RelationGetRelationName(targetrelation))));
1601
1602         relkind = targetrelation->rd_rel->relkind;
1603         relhastriggers = (targetrelation->rd_rel->reltriggers > 0);
1604
1605         /*
1606          * Find relation's pg_class tuple, and make sure newrelname isn't in use.
1607          */
1608         relrelation = heap_open(RelationRelationId, RowExclusiveLock);
1609
1610         reltup = SearchSysCacheCopy(RELOID,
1611                                                                 PointerGetDatum(myrelid),
1612                                                                 0, 0, 0);
1613         if (!HeapTupleIsValid(reltup))          /* shouldn't happen */
1614                 elog(ERROR, "cache lookup failed for relation %u", myrelid);
1615
1616         if (get_relname_relid(newrelname, namespaceId) != InvalidOid)
1617                 ereport(ERROR,
1618                                 (errcode(ERRCODE_DUPLICATE_TABLE),
1619                                  errmsg("relation \"%s\" already exists",
1620                                                 newrelname)));
1621
1622         /*
1623          * Update pg_class tuple with new relname.      (Scribbling on reltup is OK
1624          * because it's a copy...)
1625          */
1626         namestrcpy(&(((Form_pg_class) GETSTRUCT(reltup))->relname), newrelname);
1627
1628         simple_heap_update(relrelation, &reltup->t_self, reltup);
1629
1630         /* keep the system catalog indexes current */
1631         CatalogUpdateIndexes(relrelation, reltup);
1632
1633         heap_freetuple(reltup);
1634         heap_close(relrelation, RowExclusiveLock);
1635
1636         /*
1637          * Also rename the associated type, if any.
1638          */
1639         if (relkind != RELKIND_INDEX)
1640                 TypeRename(oldrelname, namespaceId, newrelname);
1641
1642         /*
1643          * Update rel name in any RI triggers associated with the relation.
1644          */
1645         if (relhastriggers)
1646         {
1647                 /* update tgargs where relname is primary key */
1648                 update_ri_trigger_args(myrelid,
1649                                                            oldrelname,
1650                                                            newrelname,
1651                                                            false, true);
1652                 /* update tgargs where relname is foreign key */
1653                 update_ri_trigger_args(myrelid,
1654                                                            oldrelname,
1655                                                            newrelname,
1656                                                            true, true);
1657         }
1658
1659         /*
1660          * Close rel, but keep exclusive lock!
1661          */
1662         relation_close(targetrelation, NoLock);
1663 }
1664
1665 /*
1666  * Scan pg_trigger for RI triggers that are on the specified relation
1667  * (if fk_scan is false) or have it as the tgconstrrel (if fk_scan
1668  * is true).  Update RI trigger args fields matching oldname to contain
1669  * newname instead.  If update_relname is true, examine the relname
1670  * fields; otherwise examine the attname fields.
1671  */
1672 static void
1673 update_ri_trigger_args(Oid relid,
1674                                            const char *oldname,
1675                                            const char *newname,
1676                                            bool fk_scan,
1677                                            bool update_relname)
1678 {
1679         Relation        tgrel;
1680         ScanKeyData skey[1];
1681         SysScanDesc trigscan;
1682         HeapTuple       tuple;
1683         Datum           values[Natts_pg_trigger];
1684         char            nulls[Natts_pg_trigger];
1685         char            replaces[Natts_pg_trigger];
1686
1687         tgrel = heap_open(TriggerRelationId, RowExclusiveLock);
1688         if (fk_scan)
1689         {
1690                 ScanKeyInit(&skey[0],
1691                                         Anum_pg_trigger_tgconstrrelid,
1692                                         BTEqualStrategyNumber, F_OIDEQ,
1693                                         ObjectIdGetDatum(relid));
1694                 trigscan = systable_beginscan(tgrel, TriggerConstrRelidIndexId,
1695                                                                           true, SnapshotNow,
1696                                                                           1, skey);
1697         }
1698         else
1699         {
1700                 ScanKeyInit(&skey[0],
1701                                         Anum_pg_trigger_tgrelid,
1702                                         BTEqualStrategyNumber, F_OIDEQ,
1703                                         ObjectIdGetDatum(relid));
1704                 trigscan = systable_beginscan(tgrel, TriggerRelidNameIndexId,
1705                                                                           true, SnapshotNow,
1706                                                                           1, skey);
1707         }
1708
1709         while ((tuple = systable_getnext(trigscan)) != NULL)
1710         {
1711                 Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
1712                 bytea      *val;
1713                 bytea      *newtgargs;
1714                 bool            isnull;
1715                 int                     tg_type;
1716                 bool            examine_pk;
1717                 bool            changed;
1718                 int                     tgnargs;
1719                 int                     i;
1720                 int                     newlen;
1721                 const char *arga[RI_MAX_ARGUMENTS];
1722                 const char *argp;
1723
1724                 tg_type = RI_FKey_trigger_type(pg_trigger->tgfoid);
1725                 if (tg_type == RI_TRIGGER_NONE)
1726                 {
1727                         /* Not an RI trigger, forget it */
1728                         continue;
1729                 }
1730
1731                 /*
1732                  * It is an RI trigger, so parse the tgargs bytea.
1733                  *
1734                  * NB: we assume the field will never be compressed or moved out of
1735                  * line; so does trigger.c ...
1736                  */
1737                 tgnargs = pg_trigger->tgnargs;
1738                 val = (bytea *)
1739                         DatumGetPointer(fastgetattr(tuple,
1740                                                                                 Anum_pg_trigger_tgargs,
1741                                                                                 tgrel->rd_att, &isnull));
1742                 if (isnull || tgnargs < RI_FIRST_ATTNAME_ARGNO ||
1743                         tgnargs > RI_MAX_ARGUMENTS)
1744                 {
1745                         /* This probably shouldn't happen, but ignore busted triggers */
1746                         continue;
1747                 }
1748                 argp = (const char *) VARDATA(val);
1749                 for (i = 0; i < tgnargs; i++)
1750                 {
1751                         arga[i] = argp;
1752                         argp += strlen(argp) + 1;
1753                 }
1754
1755                 /*
1756                  * Figure out which item(s) to look at.  If the trigger is primary-key
1757                  * type and attached to my rel, I should look at the PK fields; if it
1758                  * is foreign-key type and attached to my rel, I should look at the FK
1759                  * fields.      But the opposite rule holds when examining triggers found
1760                  * by tgconstrrel search.
1761                  */
1762                 examine_pk = (tg_type == RI_TRIGGER_PK) == (!fk_scan);
1763
1764                 changed = false;
1765                 if (update_relname)
1766                 {
1767                         /* Change the relname if needed */
1768                         i = examine_pk ? RI_PK_RELNAME_ARGNO : RI_FK_RELNAME_ARGNO;
1769                         if (strcmp(arga[i], oldname) == 0)
1770                         {
1771                                 arga[i] = newname;
1772                                 changed = true;
1773                         }
1774                 }
1775                 else
1776                 {
1777                         /* Change attname(s) if needed */
1778                         i = examine_pk ? RI_FIRST_ATTNAME_ARGNO + RI_KEYPAIR_PK_IDX :
1779                                 RI_FIRST_ATTNAME_ARGNO + RI_KEYPAIR_FK_IDX;
1780                         for (; i < tgnargs; i += 2)
1781                         {
1782                                 if (strcmp(arga[i], oldname) == 0)
1783                                 {
1784                                         arga[i] = newname;
1785                                         changed = true;
1786                                 }
1787                         }
1788                 }
1789
1790                 if (!changed)
1791                 {
1792                         /* Don't need to update this tuple */
1793                         continue;
1794                 }
1795
1796                 /*
1797                  * Construct modified tgargs bytea.
1798                  */
1799                 newlen = VARHDRSZ;
1800                 for (i = 0; i < tgnargs; i++)
1801                         newlen += strlen(arga[i]) + 1;
1802                 newtgargs = (bytea *) palloc(newlen);
1803                 VARATT_SIZEP(newtgargs) = newlen;
1804                 newlen = VARHDRSZ;
1805                 for (i = 0; i < tgnargs; i++)
1806                 {
1807                         strcpy(((char *) newtgargs) + newlen, arga[i]);
1808                         newlen += strlen(arga[i]) + 1;
1809                 }
1810
1811                 /*
1812                  * Build modified tuple.
1813                  */
1814                 for (i = 0; i < Natts_pg_trigger; i++)
1815                 {
1816                         values[i] = (Datum) 0;
1817                         replaces[i] = ' ';
1818                         nulls[i] = ' ';
1819                 }
1820                 values[Anum_pg_trigger_tgargs - 1] = PointerGetDatum(newtgargs);
1821                 replaces[Anum_pg_trigger_tgargs - 1] = 'r';
1822
1823                 tuple = heap_modifytuple(tuple, RelationGetDescr(tgrel), values, nulls, replaces);
1824
1825                 /*
1826                  * Update pg_trigger and its indexes
1827                  */
1828                 simple_heap_update(tgrel, &tuple->t_self, tuple);
1829
1830                 CatalogUpdateIndexes(tgrel, tuple);
1831
1832                 /*
1833                  * Invalidate trigger's relation's relcache entry so that other
1834                  * backends (and this one too!) are sent SI message to make them
1835                  * rebuild relcache entries.  (Ideally this should happen
1836                  * automatically...)
1837                  *
1838                  * We can skip this for triggers on relid itself, since that relcache
1839                  * flush will happen anyway due to the table or column rename.  We
1840                  * just need to catch the far ends of RI relationships.
1841                  */
1842                 pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
1843                 if (pg_trigger->tgrelid != relid)
1844                         CacheInvalidateRelcacheByRelid(pg_trigger->tgrelid);
1845
1846                 /* free up our scratch memory */
1847                 pfree(newtgargs);
1848                 heap_freetuple(tuple);
1849         }
1850
1851         systable_endscan(trigscan);
1852
1853         heap_close(tgrel, RowExclusiveLock);
1854
1855         /*
1856          * Increment cmd counter to make updates visible; this is needed in case
1857          * the same tuple has to be updated again by next pass (can happen in case
1858          * of a self-referential FK relationship).
1859          */
1860         CommandCounterIncrement();
1861 }
1862
1863 /*
1864  * AlterTable
1865  *              Execute ALTER TABLE, which can be a list of subcommands
1866  *
1867  * ALTER TABLE is performed in three phases:
1868  *              1. Examine subcommands and perform pre-transformation checking.
1869  *              2. Update system catalogs.
1870  *              3. Scan table(s) to check new constraints, and optionally recopy
1871  *                 the data into new table(s).
1872  * Phase 3 is not performed unless one or more of the subcommands requires
1873  * it.  The intention of this design is to allow multiple independent
1874  * updates of the table schema to be performed with only one pass over the
1875  * data.
1876  *
1877  * ATPrepCmd performs phase 1.  A "work queue" entry is created for
1878  * each table to be affected (there may be multiple affected tables if the
1879  * commands traverse a table inheritance hierarchy).  Also we do preliminary
1880  * validation of the subcommands, including parse transformation of those
1881  * expressions that need to be evaluated with respect to the old table
1882  * schema.
1883  *
1884  * ATRewriteCatalogs performs phase 2 for each affected table (note that
1885  * phases 2 and 3 do no explicit recursion, since phase 1 already did it).
1886  * Certain subcommands need to be performed before others to avoid
1887  * unnecessary conflicts; for example, DROP COLUMN should come before
1888  * ADD COLUMN.  Therefore phase 1 divides the subcommands into multiple
1889  * lists, one for each logical "pass" of phase 2.
1890  *
1891  * ATRewriteTables performs phase 3 for those tables that need it.
1892  *
1893  * Thanks to the magic of MVCC, an error anywhere along the way rolls back
1894  * the whole operation; we don't have to do anything special to clean up.
1895  */
1896 void
1897 AlterTable(AlterTableStmt *stmt)
1898 {
1899         ATController(relation_openrv(stmt->relation, AccessExclusiveLock),
1900                                  stmt->cmds,
1901                                  interpretInhOption(stmt->relation->inhOpt));
1902 }
1903
1904 /*
1905  * AlterTableInternal
1906  *
1907  * ALTER TABLE with target specified by OID
1908  */
1909 void
1910 AlterTableInternal(Oid relid, List *cmds, bool recurse)
1911 {
1912         ATController(relation_open(relid, AccessExclusiveLock),
1913                                  cmds,
1914                                  recurse);
1915 }
1916
1917 static void
1918 ATController(Relation rel, List *cmds, bool recurse)
1919 {
1920         List       *wqueue = NIL;
1921         ListCell   *lcmd;
1922
1923         /* Phase 1: preliminary examination of commands, create work queue */
1924         foreach(lcmd, cmds)
1925         {
1926                 AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd);
1927
1928                 ATPrepCmd(&wqueue, rel, cmd, recurse, false);
1929         }
1930
1931         /* Close the relation, but keep lock until commit */
1932         relation_close(rel, NoLock);
1933
1934         /* Phase 2: update system catalogs */
1935         ATRewriteCatalogs(&wqueue);
1936
1937         /* Phase 3: scan/rewrite tables as needed */
1938         ATRewriteTables(&wqueue);
1939 }
1940
1941 /*
1942  * ATPrepCmd
1943  *
1944  * Traffic cop for ALTER TABLE Phase 1 operations, including simple
1945  * recursion and permission checks.
1946  *
1947  * Caller must have acquired AccessExclusiveLock on relation already.
1948  * This lock should be held until commit.
1949  */
1950 static void
1951 ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
1952                   bool recurse, bool recursing)
1953 {
1954         AlteredTableInfo *tab;
1955         int                     pass;
1956
1957         /* Find or create work queue entry for this table */
1958         tab = ATGetQueueEntry(wqueue, rel);
1959
1960         /*
1961          * Copy the original subcommand for each table.  This avoids conflicts
1962          * when different child tables need to make different parse
1963          * transformations (for example, the same column may have different column
1964          * numbers in different children).
1965          */
1966         cmd = copyObject(cmd);
1967
1968         /*
1969          * Do permissions checking, recursion to child tables if needed, and any
1970          * additional phase-1 processing needed.
1971          */
1972         switch (cmd->subtype)
1973         {
1974                 case AT_AddColumn:              /* ADD COLUMN */
1975                         ATSimplePermissions(rel, false);
1976                         /* Performs own recursion */
1977                         ATPrepAddColumn(wqueue, rel, recurse, cmd);
1978                         pass = AT_PASS_ADD_COL;
1979                         break;
1980                 case AT_ColumnDefault:  /* ALTER COLUMN DEFAULT */
1981
1982                         /*
1983                          * We allow defaults on views so that INSERT into a view can have
1984                          * default-ish behavior.  This works because the rewriter
1985                          * substitutes default values into INSERTs before it expands
1986                          * rules.
1987                          */
1988                         ATSimplePermissions(rel, true);
1989                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
1990                         /* No command-specific prep needed */
1991                         pass = AT_PASS_ADD_CONSTR;
1992                         break;
1993                 case AT_DropNotNull:    /* ALTER COLUMN DROP NOT NULL */
1994                         ATSimplePermissions(rel, false);
1995                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
1996                         /* No command-specific prep needed */
1997                         pass = AT_PASS_DROP;
1998                         break;
1999                 case AT_SetNotNull:             /* ALTER COLUMN SET NOT NULL */
2000                         ATSimplePermissions(rel, false);
2001                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
2002                         /* No command-specific prep needed */
2003                         pass = AT_PASS_ADD_CONSTR;
2004                         break;
2005                 case AT_SetStatistics:  /* ALTER COLUMN STATISTICS */
2006                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
2007                         /* Performs own permission checks */
2008                         ATPrepSetStatistics(rel, cmd->name, cmd->def);
2009                         pass = AT_PASS_COL_ATTRS;
2010                         break;
2011                 case AT_SetStorage:             /* ALTER COLUMN STORAGE */
2012                         ATSimplePermissions(rel, false);
2013                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
2014                         /* No command-specific prep needed */
2015                         pass = AT_PASS_COL_ATTRS;
2016                         break;
2017                 case AT_DropColumn:             /* DROP COLUMN */
2018                         ATSimplePermissions(rel, false);
2019                         /* Recursion occurs during execution phase */
2020                         /* No command-specific prep needed except saving recurse flag */
2021                         if (recurse)
2022                                 cmd->subtype = AT_DropColumnRecurse;
2023                         pass = AT_PASS_DROP;
2024                         break;
2025                 case AT_AddIndex:               /* ADD INDEX */
2026                         ATSimplePermissions(rel, false);
2027                         /* This command never recurses */
2028                         /* No command-specific prep needed */
2029                         pass = AT_PASS_ADD_INDEX;
2030                         break;
2031                 case AT_AddConstraint:  /* ADD CONSTRAINT */
2032                         ATSimplePermissions(rel, false);
2033
2034                         /*
2035                          * Currently we recurse only for CHECK constraints, never for
2036                          * foreign-key constraints.  UNIQUE/PKEY constraints won't be seen
2037                          * here.
2038                          */
2039                         if (IsA(cmd->def, Constraint))
2040                                 ATSimpleRecursion(wqueue, rel, cmd, recurse);
2041                         /* No command-specific prep needed */
2042                         pass = AT_PASS_ADD_CONSTR;
2043                         break;
2044                 case AT_DropConstraint: /* DROP CONSTRAINT */
2045                         ATSimplePermissions(rel, false);
2046                         /* Performs own recursion */
2047                         ATPrepDropConstraint(wqueue, rel, recurse, cmd);
2048                         pass = AT_PASS_DROP;
2049                         break;
2050                 case AT_DropConstraintQuietly:  /* DROP CONSTRAINT for child */
2051                         ATSimplePermissions(rel, false);
2052                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
2053                         /* No command-specific prep needed */
2054                         pass = AT_PASS_DROP;
2055                         break;
2056                 case AT_AlterColumnType:                /* ALTER COLUMN TYPE */
2057                         ATSimplePermissions(rel, false);
2058                         /* Performs own recursion */
2059                         ATPrepAlterColumnType(wqueue, tab, rel, recurse, recursing, cmd);
2060                         pass = AT_PASS_ALTER_TYPE;
2061                         break;
2062                 case AT_ToastTable:             /* CREATE TOAST TABLE */
2063                         ATSimplePermissions(rel, false);
2064                         /* This command never recurses */
2065                         /* No command-specific prep needed */
2066                         pass = AT_PASS_MISC;
2067                         break;
2068                 case AT_ChangeOwner:    /* ALTER OWNER */
2069                         /* This command never recurses */
2070                         /* No command-specific prep needed */
2071                         pass = AT_PASS_MISC;
2072                         break;
2073                 case AT_ClusterOn:              /* CLUSTER ON */
2074                 case AT_DropCluster:    /* SET WITHOUT CLUSTER */
2075                         ATSimplePermissions(rel, false);
2076                         /* These commands never recurse */
2077                         /* No command-specific prep needed */
2078                         pass = AT_PASS_MISC;
2079                         break;
2080                 case AT_DropOids:               /* SET WITHOUT OIDS */
2081                         ATSimplePermissions(rel, false);
2082                         /* Performs own recursion */
2083                         if (rel->rd_rel->relhasoids)
2084                         {
2085                                 AlterTableCmd *dropCmd = makeNode(AlterTableCmd);
2086
2087                                 dropCmd->subtype = AT_DropColumn;
2088                                 dropCmd->name = pstrdup("oid");
2089                                 dropCmd->behavior = cmd->behavior;
2090                                 ATPrepCmd(wqueue, rel, dropCmd, recurse, false);
2091                         }
2092                         pass = AT_PASS_DROP;
2093                         break;
2094                 case AT_SetTableSpace:  /* SET TABLESPACE */
2095                         /* This command never recurses */
2096                         ATPrepSetTableSpace(tab, rel, cmd->name);
2097                         pass = AT_PASS_MISC;    /* doesn't actually matter */
2098                         break;
2099                 case AT_EnableTrig:             /* ENABLE TRIGGER variants */
2100                 case AT_EnableTrigAll:
2101                 case AT_EnableTrigUser:
2102                 case AT_DisableTrig:    /* DISABLE TRIGGER variants */
2103                 case AT_DisableTrigAll:
2104                 case AT_DisableTrigUser:
2105                 case AT_AddInherits:
2106                 case AT_DropInherits:
2107                         ATSimplePermissions(rel, false);
2108                         /* These commands never recurse */
2109                         /* No command-specific prep needed */
2110                         pass = AT_PASS_MISC;
2111                         break;
2112                 default:                                /* oops */
2113                         elog(ERROR, "unrecognized alter table type: %d",
2114                                  (int) cmd->subtype);
2115                         pass = 0;                       /* keep compiler quiet */
2116                         break;
2117         }
2118
2119         /* Add the subcommand to the appropriate list for phase 2 */
2120         tab->subcmds[pass] = lappend(tab->subcmds[pass], cmd);
2121 }
2122
2123 /*
2124  * ATRewriteCatalogs
2125  *
2126  * Traffic cop for ALTER TABLE Phase 2 operations.      Subcommands are
2127  * dispatched in a "safe" execution order (designed to avoid unnecessary
2128  * conflicts).
2129  */
2130 static void
2131 ATRewriteCatalogs(List **wqueue)
2132 {
2133         int                     pass;
2134         ListCell   *ltab;
2135
2136         /*
2137          * We process all the tables "in parallel", one pass at a time.  This is
2138          * needed because we may have to propagate work from one table to another
2139          * (specifically, ALTER TYPE on a foreign key's PK has to dispatch the
2140          * re-adding of the foreign key constraint to the other table).  Work can
2141          * only be propagated into later passes, however.
2142          */
2143         for (pass = 0; pass < AT_NUM_PASSES; pass++)
2144         {
2145                 /* Go through each table that needs to be processed */
2146                 foreach(ltab, *wqueue)
2147                 {
2148                         AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
2149                         List       *subcmds = tab->subcmds[pass];
2150                         Relation        rel;
2151                         ListCell   *lcmd;
2152
2153                         if (subcmds == NIL)
2154                                 continue;
2155
2156                         /*
2157                          * Exclusive lock was obtained by phase 1, needn't get it again
2158                          */
2159                         rel = relation_open(tab->relid, NoLock);
2160
2161                         foreach(lcmd, subcmds)
2162                                 ATExecCmd(tab, rel, (AlterTableCmd *) lfirst(lcmd));
2163
2164                         /*
2165                          * After the ALTER TYPE pass, do cleanup work (this is not done in
2166                          * ATExecAlterColumnType since it should be done only once if
2167                          * multiple columns of a table are altered).
2168                          */
2169                         if (pass == AT_PASS_ALTER_TYPE)
2170                                 ATPostAlterTypeCleanup(wqueue, tab);
2171
2172                         relation_close(rel, NoLock);
2173                 }
2174         }
2175
2176         /*
2177          * Do an implicit CREATE TOAST TABLE if we executed any subcommands that
2178          * might have added a column or changed column storage.
2179          */
2180         foreach(ltab, *wqueue)
2181         {
2182                 AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
2183
2184                 if (tab->relkind == RELKIND_RELATION &&
2185                         (tab->subcmds[AT_PASS_ADD_COL] ||
2186                          tab->subcmds[AT_PASS_ALTER_TYPE] ||
2187                          tab->subcmds[AT_PASS_COL_ATTRS]))
2188                         AlterTableCreateToastTable(tab->relid, true);
2189         }
2190 }
2191
2192 /*
2193  * ATExecCmd: dispatch a subcommand to appropriate execution routine
2194  */
2195 static void
2196 ATExecCmd(AlteredTableInfo *tab, Relation rel, AlterTableCmd *cmd)
2197 {
2198         switch (cmd->subtype)
2199         {
2200                 case AT_AddColumn:              /* ADD COLUMN */
2201                         ATExecAddColumn(tab, rel, (ColumnDef *) cmd->def);
2202                         break;
2203                 case AT_ColumnDefault:  /* ALTER COLUMN DEFAULT */
2204                         ATExecColumnDefault(rel, cmd->name, cmd->def);
2205                         break;
2206                 case AT_DropNotNull:    /* ALTER COLUMN DROP NOT NULL */
2207                         ATExecDropNotNull(rel, cmd->name);
2208                         break;
2209                 case AT_SetNotNull:             /* ALTER COLUMN SET NOT NULL */
2210                         ATExecSetNotNull(tab, rel, cmd->name);
2211                         break;
2212                 case AT_SetStatistics:  /* ALTER COLUMN STATISTICS */
2213                         ATExecSetStatistics(rel, cmd->name, cmd->def);
2214                         break;
2215                 case AT_SetStorage:             /* ALTER COLUMN STORAGE */
2216                         ATExecSetStorage(rel, cmd->name, cmd->def);
2217                         break;
2218                 case AT_DropColumn:             /* DROP COLUMN */
2219                         ATExecDropColumn(rel, cmd->name, cmd->behavior, false, false);
2220                         break;
2221                 case AT_DropColumnRecurse:              /* DROP COLUMN with recursion */
2222                         ATExecDropColumn(rel, cmd->name, cmd->behavior, true, false);
2223                         break;
2224                 case AT_AddIndex:               /* ADD INDEX */
2225                         ATExecAddIndex(tab, rel, (IndexStmt *) cmd->def, false);
2226                         break;
2227                 case AT_ReAddIndex:             /* ADD INDEX */
2228                         ATExecAddIndex(tab, rel, (IndexStmt *) cmd->def, true);
2229                         break;
2230                 case AT_AddConstraint:  /* ADD CONSTRAINT */
2231                         ATExecAddConstraint(tab, rel, cmd->def);
2232                         break;
2233                 case AT_DropConstraint: /* DROP CONSTRAINT */
2234                         ATExecDropConstraint(rel, cmd->name, cmd->behavior, false);
2235                         break;
2236                 case AT_DropConstraintQuietly:  /* DROP CONSTRAINT for child */
2237                         ATExecDropConstraint(rel, cmd->name, cmd->behavior, true);
2238                         break;
2239                 case AT_AlterColumnType:                /* ALTER COLUMN TYPE */
2240                         ATExecAlterColumnType(tab, rel, cmd->name, (TypeName *) cmd->def);
2241                         break;
2242                 case AT_ToastTable:             /* CREATE TOAST TABLE */
2243                         AlterTableCreateToastTable(RelationGetRelid(rel), false);
2244                         break;
2245                 case AT_ChangeOwner:    /* ALTER OWNER */
2246                         ATExecChangeOwner(RelationGetRelid(rel),
2247                                                           get_roleid_checked(cmd->name),
2248                                                           false);
2249                         break;
2250                 case AT_ClusterOn:              /* CLUSTER ON */
2251                         ATExecClusterOn(rel, cmd->name);
2252                         break;
2253                 case AT_DropCluster:    /* SET WITHOUT CLUSTER */
2254                         ATExecDropCluster(rel);
2255                         break;
2256                 case AT_DropOids:               /* SET WITHOUT OIDS */
2257
2258                         /*
2259                          * Nothing to do here; we'll have generated a DropColumn
2260                          * subcommand to do the real work
2261                          */
2262                         break;
2263                 case AT_SetTableSpace:  /* SET TABLESPACE */
2264
2265                         /*
2266                          * Nothing to do here; Phase 3 does the work
2267                          */
2268                         break;
2269                 case AT_EnableTrig:             /* ENABLE TRIGGER name */
2270                         ATExecEnableDisableTrigger(rel, cmd->name, true, false);
2271                         break;
2272                 case AT_DisableTrig:    /* DISABLE TRIGGER name */
2273                         ATExecEnableDisableTrigger(rel, cmd->name, false, false);
2274                         break;
2275                 case AT_EnableTrigAll:  /* ENABLE TRIGGER ALL */
2276                         ATExecEnableDisableTrigger(rel, NULL, true, false);
2277                         break;
2278                 case AT_DisableTrigAll: /* DISABLE TRIGGER ALL */
2279                         ATExecEnableDisableTrigger(rel, NULL, false, false);
2280                         break;
2281                 case AT_EnableTrigUser: /* ENABLE TRIGGER USER */
2282                         ATExecEnableDisableTrigger(rel, NULL, true, true);
2283                         break;
2284                 case AT_DisableTrigUser:                /* DISABLE TRIGGER USER */
2285                         ATExecEnableDisableTrigger(rel, NULL, false, true);
2286                         break;
2287                 case AT_DropInherits:
2288                         ATExecDropInherits(rel, cmd->parent);
2289                         break;
2290                 case AT_AddInherits:
2291                         ATExecAddInherits(rel, cmd->parent);
2292                         break;
2293                 default:                                /* oops */
2294                         elog(ERROR, "unrecognized alter table type: %d",
2295                                  (int) cmd->subtype);
2296                         break;
2297         }
2298
2299         /*
2300          * Bump the command counter to ensure the next subcommand in the sequence
2301          * can see the changes so far
2302          */
2303         CommandCounterIncrement();
2304 }
2305
2306 /*
2307  * ATRewriteTables: ALTER TABLE phase 3
2308  */
2309 static void
2310 ATRewriteTables(List **wqueue)
2311 {
2312         ListCell   *ltab;
2313
2314         /* Go through each table that needs to be checked or rewritten */
2315         foreach(ltab, *wqueue)
2316         {
2317                 AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
2318
2319                 /*
2320                  * We only need to rewrite the table if at least one column needs to
2321                  * be recomputed.
2322                  */
2323                 if (tab->newvals != NIL)
2324                 {
2325                         /* Build a temporary relation and copy data */
2326                         Oid                     OIDNewHeap;
2327                         char            NewHeapName[NAMEDATALEN];
2328                         Oid                     NewTableSpace;
2329                         Relation        OldHeap;
2330                         ObjectAddress object;
2331
2332                         OldHeap = heap_open(tab->relid, NoLock);
2333
2334                         /*
2335                          * We can never allow rewriting of shared or nailed-in-cache
2336                          * relations, because we can't support changing their relfilenode
2337                          * values.
2338                          */
2339                         if (OldHeap->rd_rel->relisshared || OldHeap->rd_isnailed)
2340                                 ereport(ERROR,
2341                                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2342                                                  errmsg("cannot rewrite system relation \"%s\"",
2343                                                                 RelationGetRelationName(OldHeap))));
2344
2345                         /*
2346                          * Don't allow rewrite on temp tables of other backends ... their
2347                          * local buffer manager is not going to cope.
2348                          */
2349                         if (isOtherTempNamespace(RelationGetNamespace(OldHeap)))
2350                                 ereport(ERROR,
2351                                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2352                                 errmsg("cannot rewrite temporary tables of other sessions")));
2353
2354                         /*
2355                          * Select destination tablespace (same as original unless user
2356                          * requested a change)
2357                          */
2358                         if (tab->newTableSpace)
2359                                 NewTableSpace = tab->newTableSpace;
2360                         else
2361                                 NewTableSpace = OldHeap->rd_rel->reltablespace;
2362
2363                         heap_close(OldHeap, NoLock);
2364
2365                         /*
2366                          * Create the new heap, using a temporary name in the same
2367                          * namespace as the existing table.  NOTE: there is some risk of
2368                          * collision with user relnames.  Working around this seems more
2369                          * trouble than it's worth; in particular, we can't create the new
2370                          * heap in a different namespace from the old, or we will have
2371                          * problems with the TEMP status of temp tables.
2372                          */
2373                         snprintf(NewHeapName, sizeof(NewHeapName),
2374                                          "pg_temp_%u", tab->relid);
2375
2376                         OIDNewHeap = make_new_heap(tab->relid, NewHeapName, NewTableSpace);
2377
2378                         /*
2379                          * Copy the heap data into the new table with the desired
2380                          * modifications, and test the current data within the table
2381                          * against new constraints generated by ALTER TABLE commands.
2382                          */
2383                         ATRewriteTable(tab, OIDNewHeap);
2384
2385                         /* Swap the physical files of the old and new heaps. */
2386                         swap_relation_files(tab->relid, OIDNewHeap);
2387
2388                         CommandCounterIncrement();
2389
2390                         /* Destroy new heap with old filenode */
2391                         object.classId = RelationRelationId;
2392                         object.objectId = OIDNewHeap;
2393                         object.objectSubId = 0;
2394
2395                         /*
2396                          * The new relation is local to our transaction and we know
2397                          * nothing depends on it, so DROP_RESTRICT should be OK.
2398                          */
2399                         performDeletion(&object, DROP_RESTRICT);
2400                         /* performDeletion does CommandCounterIncrement at end */
2401
2402                         /*
2403                          * Rebuild each index on the relation (but not the toast table,
2404                          * which is all-new anyway).  We do not need
2405                          * CommandCounterIncrement() because reindex_relation does it.
2406                          */
2407                         reindex_relation(tab->relid, false);
2408                 }
2409                 else
2410                 {
2411                         /*
2412                          * Test the current data within the table against new constraints
2413                          * generated by ALTER TABLE commands, but don't rebuild data.
2414                          */
2415                         if (tab->constraints != NIL)
2416                                 ATRewriteTable(tab, InvalidOid);
2417
2418                         /*
2419                          * If we had SET TABLESPACE but no reason to reconstruct tuples,
2420                          * just do a block-by-block copy.
2421                          */
2422                         if (tab->newTableSpace)
2423                                 ATExecSetTableSpace(tab->relid, tab->newTableSpace);
2424                 }
2425         }
2426
2427         /*
2428          * Foreign key constraints are checked in a final pass, since (a) it's
2429          * generally best to examine each one separately, and (b) it's at least
2430          * theoretically possible that we have changed both relations of the
2431          * foreign key, and we'd better have finished both rewrites before we try
2432          * to read the tables.
2433          */
2434         foreach(ltab, *wqueue)
2435         {
2436                 AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
2437                 Relation        rel = NULL;
2438                 ListCell   *lcon;
2439
2440                 foreach(lcon, tab->constraints)
2441                 {
2442                         NewConstraint *con = lfirst(lcon);
2443
2444                         if (con->contype == CONSTR_FOREIGN)
2445                         {
2446                                 FkConstraint *fkconstraint = (FkConstraint *) con->qual;
2447                                 Relation        refrel;
2448
2449                                 if (rel == NULL)
2450                                 {
2451                                         /* Long since locked, no need for another */
2452                                         rel = heap_open(tab->relid, NoLock);
2453                                 }
2454
2455                                 refrel = heap_open(con->refrelid, RowShareLock);
2456
2457                                 validateForeignKeyConstraint(fkconstraint, rel, refrel);
2458
2459                                 heap_close(refrel, NoLock);
2460                         }
2461                 }
2462
2463                 if (rel)
2464                         heap_close(rel, NoLock);
2465         }
2466 }
2467
2468 /*
2469  * ATRewriteTable: scan or rewrite one table
2470  *
2471  * OIDNewHeap is InvalidOid if we don't need to rewrite
2472  */
2473 static void
2474 ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
2475 {
2476         Relation        oldrel;
2477         Relation        newrel;
2478         TupleDesc       oldTupDesc;
2479         TupleDesc       newTupDesc;
2480         bool            needscan = false;
2481         int                     i;
2482         ListCell   *l;
2483         EState     *estate;
2484
2485         /*
2486          * Open the relation(s).  We have surely already locked the existing
2487          * table.
2488          */
2489         oldrel = heap_open(tab->relid, NoLock);
2490         oldTupDesc = tab->oldDesc;
2491         newTupDesc = RelationGetDescr(oldrel);          /* includes all mods */
2492
2493         if (OidIsValid(OIDNewHeap))
2494                 newrel = heap_open(OIDNewHeap, AccessExclusiveLock);
2495         else
2496                 newrel = NULL;
2497
2498         /*
2499          * If we need to rewrite the table, the operation has to be propagated to
2500          * tables that use this table's rowtype as a column type.
2501          *
2502          * (Eventually this will probably become true for scans as well, but at
2503          * the moment a composite type does not enforce any constraints, so it's
2504          * not necessary/appropriate to enforce them just during ALTER.)
2505          */
2506         if (newrel)
2507                 find_composite_type_dependencies(oldrel->rd_rel->reltype,
2508                                                                                  RelationGetRelationName(oldrel));
2509
2510         /*
2511          * Generate the constraint and default execution states
2512          */
2513
2514         estate = CreateExecutorState();
2515
2516         /* Build the needed expression execution states */
2517         foreach(l, tab->constraints)
2518         {
2519                 NewConstraint *con = lfirst(l);
2520
2521                 switch (con->contype)
2522                 {
2523                         case CONSTR_CHECK:
2524                                 needscan = true;
2525                                 con->qualstate = (List *)
2526                                         ExecPrepareExpr((Expr *) con->qual, estate);
2527                                 break;
2528                         case CONSTR_FOREIGN:
2529                                 /* Nothing to do here */
2530                                 break;
2531                         case CONSTR_NOTNULL:
2532                                 needscan = true;
2533                                 break;
2534                         default:
2535                                 elog(ERROR, "unrecognized constraint type: %d",
2536                                          (int) con->contype);
2537                 }
2538         }
2539
2540         foreach(l, tab->newvals)
2541         {
2542                 NewColumnValue *ex = lfirst(l);
2543
2544                 needscan = true;
2545
2546                 ex->exprstate = ExecPrepareExpr((Expr *) ex->expr, estate);
2547         }
2548
2549         if (needscan)
2550         {
2551                 ExprContext *econtext;
2552                 Datum      *values;
2553                 bool       *isnull;
2554                 TupleTableSlot *oldslot;
2555                 TupleTableSlot *newslot;
2556                 HeapScanDesc scan;
2557                 HeapTuple       tuple;
2558                 MemoryContext oldCxt;
2559                 List       *dropped_attrs = NIL;
2560                 ListCell   *lc;
2561
2562                 econtext = GetPerTupleExprContext(estate);
2563
2564                 /*
2565                  * Make tuple slots for old and new tuples.  Note that even when the
2566                  * tuples are the same, the tupDescs might not be (consider ADD COLUMN
2567                  * without a default).
2568                  */
2569                 oldslot = MakeSingleTupleTableSlot(oldTupDesc);
2570                 newslot = MakeSingleTupleTableSlot(newTupDesc);
2571
2572                 /* Preallocate values/isnull arrays */
2573                 i = Max(newTupDesc->natts, oldTupDesc->natts);
2574                 values = (Datum *) palloc(i * sizeof(Datum));
2575                 isnull = (bool *) palloc(i * sizeof(bool));
2576                 memset(values, 0, i * sizeof(Datum));
2577                 memset(isnull, true, i * sizeof(bool));
2578
2579                 /*
2580                  * Any attributes that are dropped according to the new tuple
2581                  * descriptor can be set to NULL. We precompute the list of dropped
2582                  * attributes to avoid needing to do so in the per-tuple loop.
2583                  */
2584                 for (i = 0; i < newTupDesc->natts; i++)
2585                 {
2586                         if (newTupDesc->attrs[i]->attisdropped)
2587                                 dropped_attrs = lappend_int(dropped_attrs, i);
2588                 }
2589
2590                 /*
2591                  * Scan through the rows, generating a new row if needed and then
2592                  * checking all the constraints.
2593                  */
2594                 scan = heap_beginscan(oldrel, SnapshotNow, 0, NULL);
2595
2596                 /*
2597                  * Switch to per-tuple memory context and reset it for each tuple
2598                  * produced, so we don't leak memory.
2599                  */
2600                 oldCxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(estate));
2601
2602                 while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
2603                 {
2604                         if (newrel)
2605                         {
2606                                 Oid                     tupOid = InvalidOid;
2607
2608                                 /* Extract data from old tuple */
2609                                 heap_deform_tuple(tuple, oldTupDesc, values, isnull);
2610                                 if (oldTupDesc->tdhasoid)
2611                                         tupOid = HeapTupleGetOid(tuple);
2612
2613                                 /* Set dropped attributes to null in new tuple */
2614                                 foreach(lc, dropped_attrs)
2615                                         isnull[lfirst_int(lc)] = true;
2616
2617                                 /*
2618                                  * Process supplied expressions to replace selected columns.
2619                                  * Expression inputs come from the old tuple.
2620                                  */
2621                                 ExecStoreTuple(tuple, oldslot, InvalidBuffer, false);
2622                                 econtext->ecxt_scantuple = oldslot;
2623
2624                                 foreach(l, tab->newvals)
2625                                 {
2626                                         NewColumnValue *ex = lfirst(l);
2627
2628                                         values[ex->attnum - 1] = ExecEvalExpr(ex->exprstate,
2629                                                                                                                   econtext,
2630                                                                                                          &isnull[ex->attnum - 1],
2631                                                                                                                   NULL);
2632                                 }
2633
2634                                 /*
2635                                  * Form the new tuple. Note that we don't explicitly pfree it,
2636                                  * since the per-tuple memory context will be reset shortly.
2637                                  */
2638                                 tuple = heap_form_tuple(newTupDesc, values, isnull);
2639
2640                                 /* Preserve OID, if any */
2641                                 if (newTupDesc->tdhasoid)
2642                                         HeapTupleSetOid(tuple, tupOid);
2643                         }
2644
2645                         /* Now check any constraints on the possibly-changed tuple */
2646                         ExecStoreTuple(tuple, newslot, InvalidBuffer, false);
2647                         econtext->ecxt_scantuple = newslot;
2648
2649                         foreach(l, tab->constraints)
2650                         {
2651                                 NewConstraint *con = lfirst(l);
2652
2653                                 switch (con->contype)
2654                                 {
2655                                         case CONSTR_CHECK:
2656                                                 if (!ExecQual(con->qualstate, econtext, true))
2657                                                         ereport(ERROR,
2658                                                                         (errcode(ERRCODE_CHECK_VIOLATION),
2659                                                                          errmsg("check constraint \"%s\" is violated by some row",
2660                                                                                         con->name)));
2661                                                 break;
2662                                         case CONSTR_NOTNULL:
2663                                                 {
2664                                                         Datum           d;
2665                                                         bool            isnull;
2666
2667                                                         d = heap_getattr(tuple, con->attnum, newTupDesc,
2668                                                                                          &isnull);
2669                                                         if (isnull)
2670                                                                 ereport(ERROR,
2671                                                                                 (errcode(ERRCODE_NOT_NULL_VIOLATION),
2672                                                                  errmsg("column \"%s\" contains null values",
2673                                                                                 get_attname(tab->relid,
2674                                                                                                         con->attnum))));
2675                                                 }
2676                                                 break;
2677                                         case CONSTR_FOREIGN:
2678                                                 /* Nothing to do here */
2679                                                 break;
2680                                         default:
2681                                                 elog(ERROR, "unrecognized constraint type: %d",
2682                                                          (int) con->contype);
2683                                 }
2684                         }
2685
2686                         /* Write the tuple out to the new relation */
2687                         if (newrel)
2688                                 simple_heap_insert(newrel, tuple);
2689
2690                         ResetExprContext(econtext);
2691
2692                         CHECK_FOR_INTERRUPTS();
2693                 }
2694
2695                 MemoryContextSwitchTo(oldCxt);
2696                 heap_endscan(scan);
2697
2698                 ExecDropSingleTupleTableSlot(oldslot);
2699                 ExecDropSingleTupleTableSlot(newslot);
2700         }
2701
2702         FreeExecutorState(estate);
2703
2704         heap_close(oldrel, NoLock);
2705         if (newrel)
2706                 heap_close(newrel, NoLock);
2707 }
2708
2709 /*
2710  * ATGetQueueEntry: find or create an entry in the ALTER TABLE work queue
2711  */
2712 static AlteredTableInfo *
2713 ATGetQueueEntry(List **wqueue, Relation rel)
2714 {
2715         Oid                     relid = RelationGetRelid(rel);
2716         AlteredTableInfo *tab;
2717         ListCell   *ltab;
2718
2719         foreach(ltab, *wqueue)
2720         {
2721                 tab = (AlteredTableInfo *) lfirst(ltab);
2722                 if (tab->relid == relid)
2723                         return tab;
2724         }
2725
2726         /*
2727          * Not there, so add it.  Note that we make a copy of the relation's
2728          * existing descriptor before anything interesting can happen to it.
2729          */
2730         tab = (AlteredTableInfo *) palloc0(sizeof(AlteredTableInfo));
2731         tab->relid = relid;
2732         tab->relkind = rel->rd_rel->relkind;
2733         tab->oldDesc = CreateTupleDescCopy(RelationGetDescr(rel));
2734
2735         *wqueue = lappend(*wqueue, tab);
2736
2737         return tab;
2738 }
2739
2740 /*
2741  * ATSimplePermissions
2742  *
2743  * - Ensure that it is a relation (or possibly a view)
2744  * - Ensure this user is the owner
2745  * - Ensure that it is not a system table
2746  */
2747 static void
2748 ATSimplePermissions(Relation rel, bool allowView)
2749 {
2750         if (rel->rd_rel->relkind != RELKIND_RELATION)
2751         {
2752                 if (allowView)
2753                 {
2754                         if (rel->rd_rel->relkind != RELKIND_VIEW)
2755                                 ereport(ERROR,
2756                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
2757                                                  errmsg("\"%s\" is not a table or view",
2758                                                                 RelationGetRelationName(rel))));
2759                 }
2760                 else
2761                         ereport(ERROR,
2762                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
2763                                          errmsg("\"%s\" is not a table",
2764                                                         RelationGetRelationName(rel))));
2765         }
2766
2767         /* Permissions checks */
2768         if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
2769                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
2770                                            RelationGetRelationName(rel));
2771
2772         if (!allowSystemTableMods && IsSystemRelation(rel))
2773                 ereport(ERROR,
2774                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
2775                                  errmsg("permission denied: \"%s\" is a system catalog",
2776                                                 RelationGetRelationName(rel))));
2777 }
2778
2779 /*
2780  * ATSimpleRecursion
2781  *
2782  * Simple table recursion sufficient for most ALTER TABLE operations.
2783  * All direct and indirect children are processed in an unspecified order.
2784  * Note that if a child inherits from the original table via multiple
2785  * inheritance paths, it will be visited just once.
2786  */
2787 static void
2788 ATSimpleRecursion(List **wqueue, Relation rel,
2789                                   AlterTableCmd *cmd, bool recurse)
2790 {
2791         /*
2792          * Propagate to children if desired.  Non-table relations never have
2793          * children, so no need to search in that case.
2794          */
2795         if (recurse && rel->rd_rel->relkind == RELKIND_RELATION)
2796         {
2797                 Oid                     relid = RelationGetRelid(rel);
2798                 ListCell   *child;
2799                 List       *children;
2800
2801                 /* this routine is actually in the planner */
2802                 children = find_all_inheritors(relid);
2803
2804                 /*
2805                  * find_all_inheritors does the recursive search of the inheritance
2806                  * hierarchy, so all we have to do is process all of the relids in the
2807                  * list that it returns.
2808                  */
2809                 foreach(child, children)
2810                 {
2811                         Oid                     childrelid = lfirst_oid(child);
2812                         Relation        childrel;
2813
2814                         if (childrelid == relid)
2815                                 continue;
2816                         childrel = relation_open(childrelid, AccessExclusiveLock);
2817                         ATPrepCmd(wqueue, childrel, cmd, false, true);
2818                         relation_close(childrel, NoLock);
2819                 }
2820         }
2821 }
2822
2823 /*
2824  * ATOneLevelRecursion
2825  *
2826  * Here, we visit only direct inheritance children.  It is expected that
2827  * the command's prep routine will recurse again to find indirect children.
2828  * When using this technique, a multiply-inheriting child will be visited
2829  * multiple times.
2830  */
2831 static void
2832 ATOneLevelRecursion(List **wqueue, Relation rel,
2833                                         AlterTableCmd *cmd)
2834 {
2835         Oid                     relid = RelationGetRelid(rel);
2836         ListCell   *child;
2837         List       *children;
2838
2839         /* this routine is actually in the planner */
2840         children = find_inheritance_children(relid);
2841
2842         foreach(child, children)
2843         {
2844                 Oid                     childrelid = lfirst_oid(child);
2845                 Relation        childrel;
2846
2847                 childrel = relation_open(childrelid, AccessExclusiveLock);
2848                 ATPrepCmd(wqueue, childrel, cmd, true, true);
2849                 relation_close(childrel, NoLock);
2850         }
2851 }
2852
2853
2854 /*
2855  * find_composite_type_dependencies
2856  *
2857  * Check to see if a table's rowtype is being used as a column in some
2858  * other table (possibly nested several levels deep in composite types!).
2859  * Eventually, we'd like to propagate the check or rewrite operation
2860  * into other such tables, but for now, just error out if we find any.
2861  *
2862  * We assume that functions and views depending on the type are not reasons
2863  * to reject the ALTER.  (How safe is this really?)
2864  */
2865 static void
2866 find_composite_type_dependencies(Oid typeOid, const char *origTblName)
2867 {
2868         Relation        depRel;
2869         ScanKeyData key[2];
2870         SysScanDesc depScan;
2871         HeapTuple       depTup;
2872
2873         /*
2874          * We scan pg_depend to find those things that depend on the rowtype. (We
2875          * assume we can ignore refobjsubid for a rowtype.)
2876          */
2877         depRel = heap_open(DependRelationId, AccessShareLock);
2878
2879         ScanKeyInit(&key[0],
2880                                 Anum_pg_depend_refclassid,
2881                                 BTEqualStrategyNumber, F_OIDEQ,
2882                                 ObjectIdGetDatum(TypeRelationId));
2883         ScanKeyInit(&key[1],
2884                                 Anum_pg_depend_refobjid,
2885                                 BTEqualStrategyNumber, F_OIDEQ,
2886                                 ObjectIdGetDatum(typeOid));
2887
2888         depScan = systable_beginscan(depRel, DependReferenceIndexId, true,
2889                                                                  SnapshotNow, 2, key);
2890
2891         while (HeapTupleIsValid(depTup = systable_getnext(depScan)))
2892         {
2893                 Form_pg_depend pg_depend = (Form_pg_depend) GETSTRUCT(depTup);
2894                 Relation        rel;
2895                 Form_pg_attribute att;
2896
2897                 /* Ignore dependees that aren't user columns of relations */
2898                 /* (we assume system columns are never of rowtypes) */
2899                 if (pg_depend->classid != RelationRelationId ||
2900                         pg_depend->objsubid <= 0)
2901                         continue;
2902
2903                 rel = relation_open(pg_depend->objid, AccessShareLock);
2904                 att = rel->rd_att->attrs[pg_depend->objsubid - 1];
2905
2906                 if (rel->rd_rel->relkind == RELKIND_RELATION)
2907                 {
2908                         ereport(ERROR,
2909                                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2910                                          errmsg("cannot alter table \"%s\" because column \"%s\".\"%s\" uses its rowtype",
2911                                                         origTblName,
2912                                                         RelationGetRelationName(rel),
2913                                                         NameStr(att->attname))));
2914                 }
2915                 else if (OidIsValid(rel->rd_rel->reltype))
2916                 {
2917                         /*
2918                          * A view or composite type itself isn't a problem, but we must
2919                          * recursively check for indirect dependencies via its rowtype.
2920                          */
2921                         find_composite_type_dependencies(rel->rd_rel->reltype,
2922                                                                                          origTblName);
2923                 }
2924
2925                 relation_close(rel, AccessShareLock);
2926         }
2927
2928         systable_endscan(depScan);
2929
2930         relation_close(depRel, AccessShareLock);
2931 }
2932
2933
2934 /*
2935  * ALTER TABLE ADD COLUMN
2936  *
2937  * Adds an additional attribute to a relation making the assumption that
2938  * CHECK, NOT NULL, and FOREIGN KEY constraints will be removed from the
2939  * AT_AddColumn AlterTableCmd by analyze.c and added as independent
2940  * AlterTableCmd's.
2941  */
2942 static void
2943 ATPrepAddColumn(List **wqueue, Relation rel, bool recurse,
2944                                 AlterTableCmd *cmd)
2945 {
2946         /*
2947          * Recurse to add the column to child classes, if requested.
2948          *
2949          * We must recurse one level at a time, so that multiply-inheriting
2950          * children are visited the right number of times and end up with the
2951          * right attinhcount.
2952          */
2953         if (recurse)
2954         {
2955                 AlterTableCmd *childCmd = copyObject(cmd);
2956                 ColumnDef  *colDefChild = (ColumnDef *) childCmd->def;
2957
2958                 /* Child should see column as singly inherited */
2959                 colDefChild->inhcount = 1;
2960                 colDefChild->is_local = false;
2961                 /* and don't make a support dependency on the child */
2962                 colDefChild->support = NULL;
2963
2964                 ATOneLevelRecursion(wqueue, rel, childCmd);
2965         }
2966         else
2967         {
2968                 /*
2969                  * If we are told not to recurse, there had better not be any child
2970                  * tables; else the addition would put them out of step.
2971                  */
2972                 if (find_inheritance_children(RelationGetRelid(rel)) != NIL)
2973                         ereport(ERROR,
2974                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
2975                                          errmsg("column must be added to child tables too")));
2976         }
2977 }
2978
2979 static void
2980 ATExecAddColumn(AlteredTableInfo *tab, Relation rel,
2981                                 ColumnDef *colDef)
2982 {
2983         Oid                     myrelid = RelationGetRelid(rel);
2984         Relation        pgclass,
2985                                 attrdesc;
2986         HeapTuple       reltup;
2987         HeapTuple       attributeTuple;
2988         Form_pg_attribute attribute;
2989         FormData_pg_attribute attributeD;
2990         int                     i;
2991         int                     minattnum,
2992                                 maxatts;
2993         HeapTuple       typeTuple;
2994         Oid                     typeOid;
2995         Form_pg_type tform;
2996         Expr       *defval;
2997
2998         attrdesc = heap_open(AttributeRelationId, RowExclusiveLock);
2999
3000         /*
3001          * Are we adding the column to a recursion child?  If so, check whether to
3002          * merge with an existing definition for the column.
3003          */
3004         if (colDef->inhcount > 0)
3005         {
3006                 HeapTuple       tuple;
3007
3008                 /* Does child already have a column by this name? */
3009                 tuple = SearchSysCacheCopyAttName(myrelid, colDef->colname);
3010                 if (HeapTupleIsValid(tuple))
3011                 {
3012                         Form_pg_attribute childatt = (Form_pg_attribute) GETSTRUCT(tuple);
3013
3014                         /* Okay if child matches by type */
3015                         if (typenameTypeId(NULL, colDef->typename) != childatt->atttypid ||
3016                                 colDef->typename->typmod != childatt->atttypmod)
3017                                 ereport(ERROR,
3018                                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
3019                                                  errmsg("child table \"%s\" has different type for column \"%s\"",
3020                                                         RelationGetRelationName(rel), colDef->colname)));
3021
3022                         /* Bump the existing child att's inhcount */
3023                         childatt->attinhcount++;
3024                         simple_heap_update(attrdesc, &tuple->t_self, tuple);
3025                         CatalogUpdateIndexes(attrdesc, tuple);
3026
3027                         heap_freetuple(tuple);
3028
3029                         /* Inform the user about the merge */
3030                         ereport(NOTICE,
3031                           (errmsg("merging definition of column \"%s\" for child \"%s\"",
3032                                           colDef->colname, RelationGetRelationName(rel))));
3033
3034                         heap_close(attrdesc, RowExclusiveLock);
3035                         return;
3036                 }
3037         }
3038
3039         pgclass = heap_open(RelationRelationId, RowExclusiveLock);
3040
3041         reltup = SearchSysCacheCopy(RELOID,
3042                                                                 ObjectIdGetDatum(myrelid),
3043                                                                 0, 0, 0);
3044         if (!HeapTupleIsValid(reltup))
3045                 elog(ERROR, "cache lookup failed for relation %u", myrelid);
3046
3047         /*
3048          * this test is deliberately not attisdropped-aware, since if one tries to
3049          * add a column matching a dropped column name, it's gonna fail anyway.
3050          */
3051         if (SearchSysCacheExists(ATTNAME,
3052                                                          ObjectIdGetDatum(myrelid),
3053                                                          PointerGetDatum(colDef->colname),
3054                                                          0, 0))
3055                 ereport(ERROR,
3056                                 (errcode(ERRCODE_DUPLICATE_COLUMN),
3057                                  errmsg("column \"%s\" of relation \"%s\" already exists",
3058                                                 colDef->colname, RelationGetRelationName(rel))));
3059
3060         minattnum = ((Form_pg_class) GETSTRUCT(reltup))->relnatts;
3061         maxatts = minattnum + 1;
3062         if (maxatts > MaxHeapAttributeNumber)
3063                 ereport(ERROR,
3064                                 (errcode(ERRCODE_TOO_MANY_COLUMNS),
3065                                  errmsg("tables can have at most %d columns",
3066                                                 MaxHeapAttributeNumber)));
3067         i = minattnum + 1;
3068
3069         typeTuple = typenameType(NULL, colDef->typename);
3070         tform = (Form_pg_type) GETSTRUCT(typeTuple);
3071         typeOid = HeapTupleGetOid(typeTuple);
3072
3073         /* make sure datatype is legal for a column */
3074         CheckAttributeType(colDef->colname, typeOid);
3075
3076         attributeTuple = heap_addheader(Natts_pg_attribute,
3077                                                                         false,
3078                                                                         ATTRIBUTE_TUPLE_SIZE,
3079                                                                         (void *) &attributeD);
3080
3081         attribute = (Form_pg_attribute) GETSTRUCT(attributeTuple);
3082
3083         attribute->attrelid = myrelid;
3084         namestrcpy(&(attribute->attname), colDef->colname);
3085         attribute->atttypid = typeOid;
3086         attribute->attstattarget = -1;
3087         attribute->attlen = tform->typlen;
3088         attribute->attcacheoff = -1;
3089         attribute->atttypmod = colDef->typename->typmod;
3090         attribute->attnum = i;
3091         attribute->attbyval = tform->typbyval;
3092         attribute->attndims = list_length(colDef->typename->arrayBounds);
3093         attribute->attstorage = tform->typstorage;
3094         attribute->attalign = tform->typalign;
3095         attribute->attnotnull = colDef->is_not_null;
3096         attribute->atthasdef = false;
3097         attribute->attisdropped = false;
3098         attribute->attislocal = colDef->is_local;
3099         attribute->attinhcount = colDef->inhcount;
3100
3101         ReleaseSysCache(typeTuple);
3102
3103         simple_heap_insert(attrdesc, attributeTuple);
3104
3105         /* Update indexes on pg_attribute */
3106         CatalogUpdateIndexes(attrdesc, attributeTuple);
3107
3108         heap_close(attrdesc, RowExclusiveLock);
3109
3110         /*
3111          * Update number of attributes in pg_class tuple
3112          */
3113         ((Form_pg_class) GETSTRUCT(reltup))->relnatts = maxatts;
3114
3115         simple_heap_update(pgclass, &reltup->t_self, reltup);
3116
3117         /* keep catalog indexes current */
3118         CatalogUpdateIndexes(pgclass, reltup);
3119
3120         heap_freetuple(reltup);
3121
3122         heap_close(pgclass, RowExclusiveLock);
3123
3124         /* Make the attribute's catalog entry visible */
3125         CommandCounterIncrement();
3126
3127         /*
3128          * Store the DEFAULT, if any, in the catalogs
3129          */
3130         if (colDef->raw_default)
3131         {
3132                 RawColumnDefault *rawEnt;
3133
3134                 rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
3135                 rawEnt->attnum = attribute->attnum;
3136                 rawEnt->raw_default = copyObject(colDef->raw_default);
3137
3138                 /*
3139                  * This function is intended for CREATE TABLE, so it processes a
3140                  * _list_ of defaults, but we just do one.
3141                  */
3142                 AddRelationRawConstraints(rel, list_make1(rawEnt), NIL);
3143
3144                 /* Make the additional catalog changes visible */
3145                 CommandCounterIncrement();
3146         }
3147
3148         /*
3149          * Tell Phase 3 to fill in the default expression, if there is one.
3150          *
3151          * If there is no default, Phase 3 doesn't have to do anything, because
3152          * that effectively means that the default is NULL.  The heap tuple access
3153          * routines always check for attnum > # of attributes in tuple, and return
3154          * NULL if so, so without any modification of the tuple data we will get
3155          * the effect of NULL values in the new column.
3156          *
3157          * An exception occurs when the new column is of a domain type: the domain
3158          * might have a NOT NULL constraint, or a check constraint that indirectly
3159          * rejects nulls.  If there are any domain constraints then we construct
3160          * an explicit NULL default value that will be passed through
3161          * CoerceToDomain processing.  (This is a tad inefficient, since it causes
3162          * rewriting the table which we really don't have to do, but the present
3163          * design of domain processing doesn't offer any simple way of checking
3164          * the constraints more directly.)
3165          *
3166          * Note: we use build_column_default, and not just the cooked default
3167          * returned by AddRelationRawConstraints, so that the right thing happens
3168          * when a datatype's default applies.
3169          */
3170         defval = (Expr *) build_column_default(rel, attribute->attnum);
3171
3172         if (!defval && GetDomainConstraints(typeOid) != NIL)
3173         {
3174                 Oid                     basetype = getBaseType(typeOid);
3175
3176                 defval = (Expr *) makeNullConst(basetype);
3177                 defval = (Expr *) coerce_to_target_type(NULL,
3178                                                                                                 (Node *) defval,
3179                                                                                                 basetype,
3180                                                                                                 typeOid,
3181                                                                                                 colDef->typename->typmod,
3182                                                                                                 COERCION_ASSIGNMENT,
3183                                                                                                 COERCE_IMPLICIT_CAST);
3184                 if (defval == NULL)             /* should not happen */
3185                         elog(ERROR, "failed to coerce base type to domain");
3186         }
3187
3188         if (defval)
3189         {
3190                 NewColumnValue *newval;
3191
3192                 newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
3193                 newval->attnum = attribute->attnum;
3194                 newval->expr = defval;
3195
3196                 tab->newvals = lappend(tab->newvals, newval);
3197         }
3198
3199         /*
3200          * Add needed dependency entries for the new column.
3201          */
3202         add_column_datatype_dependency(myrelid, i, attribute->atttypid);
3203         if (colDef->support != NULL)
3204                 add_column_support_dependency(myrelid, i, colDef->support);
3205 }
3206
3207 /*
3208  * Install a column's dependency on its datatype.
3209  */
3210 static void
3211 add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid)
3212 {
3213         ObjectAddress myself,
3214                                 referenced;
3215
3216         myself.classId = RelationRelationId;
3217         myself.objectId = relid;
3218         myself.objectSubId = attnum;
3219         referenced.classId = TypeRelationId;
3220         referenced.objectId = typid;
3221         referenced.objectSubId = 0;
3222         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
3223 }
3224
3225 /*
3226  * Install a dependency for a column's supporting relation (serial sequence).
3227  */
3228 static void
3229 add_column_support_dependency(Oid relid, int32 attnum, RangeVar *support)
3230 {
3231         ObjectAddress colobject,
3232                                 suppobject;
3233
3234         colobject.classId = RelationRelationId;
3235         colobject.objectId = relid;
3236         colobject.objectSubId = attnum;
3237         suppobject.classId = RelationRelationId;
3238         suppobject.objectId = RangeVarGetRelid(support, false);
3239         suppobject.objectSubId = 0;
3240         recordDependencyOn(&suppobject, &colobject, DEPENDENCY_INTERNAL);
3241 }
3242
3243 /*
3244  * ALTER TABLE ALTER COLUMN DROP NOT NULL
3245  */
3246 static void
3247 ATExecDropNotNull(Relation rel, const char *colName)
3248 {
3249         HeapTuple       tuple;
3250         AttrNumber      attnum;
3251         Relation        attr_rel;
3252         List       *indexoidlist;
3253         ListCell   *indexoidscan;
3254
3255         /*
3256          * lookup the attribute
3257          */
3258         attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
3259
3260         tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
3261
3262         if (!HeapTupleIsValid(tuple))
3263                 ereport(ERROR,
3264                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3265                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3266                                                 colName, RelationGetRelationName(rel))));
3267
3268         attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
3269
3270         /* Prevent them from altering a system attribute */
3271         if (attnum <= 0)
3272                 ereport(ERROR,
3273                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3274                                  errmsg("cannot alter system column \"%s\"",
3275                                                 colName)));
3276
3277         /*
3278          * Check that the attribute is not in a primary key
3279          */
3280
3281         /* Loop over all indexes on the relation */
3282         indexoidlist = RelationGetIndexList(rel);
3283
3284         foreach(indexoidscan, indexoidlist)
3285         {
3286                 Oid                     indexoid = lfirst_oid(indexoidscan);
3287                 HeapTuple       indexTuple;
3288                 Form_pg_index indexStruct;
3289                 int                     i;
3290
3291                 indexTuple = SearchSysCache(INDEXRELID,
3292                                                                         ObjectIdGetDatum(indexoid),
3293                                                                         0, 0, 0);
3294                 if (!HeapTupleIsValid(indexTuple))
3295                         elog(ERROR, "cache lookup failed for index %u", indexoid);
3296                 indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
3297
3298                 /* If the index is not a primary key, skip the check */
3299                 if (indexStruct->indisprimary)
3300                 {
3301                         /*
3302                          * Loop over each attribute in the primary key and see if it
3303                          * matches the to-be-altered attribute
3304                          */
3305                         for (i = 0; i < indexStruct->indnatts; i++)
3306                         {
3307                                 if (indexStruct->indkey.values[i] == attnum)
3308                                         ereport(ERROR,
3309                                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
3310                                                          errmsg("column \"%s\" is in a primary key",
3311                                                                         colName)));
3312                         }
3313                 }
3314
3315                 ReleaseSysCache(indexTuple);
3316         }
3317
3318         list_free(indexoidlist);
3319
3320         /*
3321          * Okay, actually perform the catalog change ... if needed
3322          */
3323         if (((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull)
3324         {
3325                 ((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = FALSE;
3326
3327                 simple_heap_update(attr_rel, &tuple->t_self, tuple);
3328
3329                 /* keep the system catalog indexes current */
3330                 CatalogUpdateIndexes(attr_rel, tuple);
3331         }
3332
3333         heap_close(attr_rel, RowExclusiveLock);
3334 }
3335
3336 /*
3337  * ALTER TABLE ALTER COLUMN SET NOT NULL
3338  */
3339 static void
3340 ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
3341                                  const char *colName)
3342 {
3343         HeapTuple       tuple;
3344         AttrNumber      attnum;
3345         Relation        attr_rel;
3346         NewConstraint *newcon;
3347
3348         /*
3349          * lookup the attribute
3350          */
3351         attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
3352
3353         tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
3354
3355         if (!HeapTupleIsValid(tuple))
3356                 ereport(ERROR,
3357                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3358                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3359                                                 colName, RelationGetRelationName(rel))));
3360
3361         attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
3362
3363         /* Prevent them from altering a system attribute */
3364         if (attnum <= 0)
3365                 ereport(ERROR,
3366                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3367                                  errmsg("cannot alter system column \"%s\"",
3368                                                 colName)));
3369
3370         /*
3371          * Okay, actually perform the catalog change ... if needed
3372          */
3373         if (!((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull)
3374         {
3375                 ((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = TRUE;
3376
3377                 simple_heap_update(attr_rel, &tuple->t_self, tuple);
3378
3379                 /* keep the system catalog indexes current */
3380                 CatalogUpdateIndexes(attr_rel, tuple);
3381
3382                 /* Tell Phase 3 to test the constraint */
3383                 newcon = (NewConstraint *) palloc0(sizeof(NewConstraint));
3384                 newcon->contype = CONSTR_NOTNULL;
3385                 newcon->attnum = attnum;
3386                 newcon->name = "NOT NULL";
3387
3388                 tab->constraints = lappend(tab->constraints, newcon);
3389         }
3390
3391         heap_close(attr_rel, RowExclusiveLock);
3392 }
3393
3394 /*
3395  * ALTER TABLE ALTER COLUMN SET/DROP DEFAULT
3396  */
3397 static void
3398 ATExecColumnDefault(Relation rel, const char *colName,
3399                                         Node *newDefault)
3400 {
3401         AttrNumber      attnum;
3402
3403         /*
3404          * get the number of the attribute
3405          */
3406         attnum = get_attnum(RelationGetRelid(rel), colName);
3407         if (attnum == InvalidAttrNumber)
3408                 ereport(ERROR,
3409                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3410                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3411                                                 colName, RelationGetRelationName(rel))));
3412
3413         /* Prevent them from altering a system attribute */
3414         if (attnum <= 0)
3415                 ereport(ERROR,
3416                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3417                                  errmsg("cannot alter system column \"%s\"",
3418                                                 colName)));
3419
3420         /*
3421          * Remove any old default for the column.  We use RESTRICT here for
3422          * safety, but at present we do not expect anything to depend on the
3423          * default.
3424          */
3425         RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, false);
3426
3427         if (newDefault)
3428         {
3429                 /* SET DEFAULT */
3430                 RawColumnDefault *rawEnt;
3431
3432                 rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
3433                 rawEnt->attnum = attnum;
3434                 rawEnt->raw_default = newDefault;
3435
3436                 /*
3437                  * This function is intended for CREATE TABLE, so it processes a
3438                  * _list_ of defaults, but we just do one.
3439                  */
3440                 AddRelationRawConstraints(rel, list_make1(rawEnt), NIL);
3441         }
3442 }
3443
3444 /*
3445  * ALTER TABLE ALTER COLUMN SET STATISTICS
3446  */
3447 static void
3448 ATPrepSetStatistics(Relation rel, const char *colName, Node *flagValue)
3449 {
3450         /*
3451          * We do our own permission checking because (a) we want to allow SET
3452          * STATISTICS on indexes (for expressional index columns), and (b) we want
3453          * to allow SET STATISTICS on system catalogs without requiring
3454          * allowSystemTableMods to be turned on.
3455          */
3456         if (rel->rd_rel->relkind != RELKIND_RELATION &&
3457                 rel->rd_rel->relkind != RELKIND_INDEX)
3458                 ereport(ERROR,
3459                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
3460                                  errmsg("\"%s\" is not a table or index",
3461                                                 RelationGetRelationName(rel))));
3462
3463         /* Permissions checks */
3464         if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
3465                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
3466                                            RelationGetRelationName(rel));
3467 }
3468
3469 static void
3470 ATExecSetStatistics(Relation rel, const char *colName, Node *newValue)
3471 {
3472         int                     newtarget;
3473         Relation        attrelation;
3474         HeapTuple       tuple;
3475         Form_pg_attribute attrtuple;
3476
3477         Assert(IsA(newValue, Integer));
3478         newtarget = intVal(newValue);
3479
3480         /*
3481          * Limit target to a sane range
3482          */
3483         if (newtarget < -1)
3484         {
3485                 ereport(ERROR,
3486                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
3487                                  errmsg("statistics target %d is too low",
3488                                                 newtarget)));
3489         }
3490         else if (newtarget > 1000)
3491         {
3492                 newtarget = 1000;
3493                 ereport(WARNING,
3494                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
3495                                  errmsg("lowering statistics target to %d",
3496                                                 newtarget)));
3497         }
3498
3499         attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
3500
3501         tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
3502
3503         if (!HeapTupleIsValid(tuple))
3504                 ereport(ERROR,
3505                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3506                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3507                                                 colName, RelationGetRelationName(rel))));
3508         attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
3509
3510         if (attrtuple->attnum <= 0)
3511                 ereport(ERROR,
3512                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3513                                  errmsg("cannot alter system column \"%s\"",
3514                                                 colName)));
3515
3516         attrtuple->attstattarget = newtarget;
3517
3518         simple_heap_update(attrelation, &tuple->t_self, tuple);
3519
3520         /* keep system catalog indexes current */
3521         CatalogUpdateIndexes(attrelation, tuple);
3522
3523         heap_freetuple(tuple);
3524
3525         heap_close(attrelation, RowExclusiveLock);
3526 }
3527
3528 /*
3529  * ALTER TABLE ALTER COLUMN SET STORAGE
3530  */
3531 static void
3532 ATExecSetStorage(Relation rel, const char *colName, Node *newValue)
3533 {
3534         char       *storagemode;
3535         char            newstorage;
3536         Relation        attrelation;
3537         HeapTuple       tuple;
3538         Form_pg_attribute attrtuple;
3539
3540         Assert(IsA(newValue, String));
3541         storagemode = strVal(newValue);
3542
3543         if (pg_strcasecmp(storagemode, "plain") == 0)
3544                 newstorage = 'p';
3545         else if (pg_strcasecmp(storagemode, "external") == 0)
3546                 newstorage = 'e';
3547         else if (pg_strcasecmp(storagemode, "extended") == 0)
3548                 newstorage = 'x';
3549         else if (pg_strcasecmp(storagemode, "main") == 0)
3550                 newstorage = 'm';
3551         else
3552         {
3553                 ereport(ERROR,
3554                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
3555                                  errmsg("invalid storage type \"%s\"",
3556                                                 storagemode)));
3557                 newstorage = 0;                 /* keep compiler quiet */
3558         }
3559
3560         attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
3561
3562         tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
3563
3564         if (!HeapTupleIsValid(tuple))
3565                 ereport(ERROR,
3566                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3567                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3568                                                 colName, RelationGetRelationName(rel))));
3569         attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
3570
3571         if (attrtuple->attnum <= 0)
3572                 ereport(ERROR,
3573                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3574                                  errmsg("cannot alter system column \"%s\"",
3575                                                 colName)));
3576
3577         /*
3578          * safety check: do not allow toasted storage modes unless column datatype
3579          * is TOAST-aware.
3580          */
3581         if (newstorage == 'p' || TypeIsToastable(attrtuple->atttypid))
3582                 attrtuple->attstorage = newstorage;
3583         else
3584                 ereport(ERROR,
3585                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3586                                  errmsg("column data type %s can only have storage PLAIN",
3587                                                 format_type_be(attrtuple->atttypid))));
3588
3589         simple_heap_update(attrelation, &tuple->t_self, tuple);
3590
3591         /* keep system catalog indexes current */
3592         CatalogUpdateIndexes(attrelation, tuple);
3593
3594         heap_freetuple(tuple);
3595
3596         heap_close(attrelation, RowExclusiveLock);
3597 }
3598
3599
3600 /*
3601  * ALTER TABLE DROP COLUMN
3602  *
3603  * DROP COLUMN cannot use the normal ALTER TABLE recursion mechanism,
3604  * because we have to decide at runtime whether to recurse or not depending
3605  * on whether attinhcount goes to zero or not.  (We can't check this in a
3606  * static pre-pass because it won't handle multiple inheritance situations
3607  * correctly.)  Since DROP COLUMN doesn't need to create any work queue
3608  * entries for Phase 3, it's okay to recurse internally in this routine
3609  * without considering the work queue.
3610  */
3611 static void
3612 ATExecDropColumn(Relation rel, const char *colName,
3613                                  DropBehavior behavior,
3614                                  bool recurse, bool recursing)
3615 {
3616         HeapTuple       tuple;
3617         Form_pg_attribute targetatt;
3618         AttrNumber      attnum;
3619         List       *children;
3620         ObjectAddress object;
3621
3622         /* At top level, permission check was done in ATPrepCmd, else do it */
3623         if (recursing)
3624                 ATSimplePermissions(rel, false);
3625
3626         /*
3627          * get the number of the attribute
3628          */
3629         tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
3630         if (!HeapTupleIsValid(tuple))
3631                 ereport(ERROR,
3632                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3633                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3634                                                 colName, RelationGetRelationName(rel))));
3635         targetatt = (Form_pg_attribute) GETSTRUCT(tuple);
3636
3637         attnum = targetatt->attnum;
3638
3639         /* Can't drop a system attribute, except OID */
3640         if (attnum <= 0 && attnum != ObjectIdAttributeNumber)
3641                 ereport(ERROR,
3642                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3643                                  errmsg("cannot drop system column \"%s\"",
3644                                                 colName)));
3645
3646         /* Don't drop inherited columns */
3647         if (targetatt->attinhcount > 0 && !recursing)
3648                 ereport(ERROR,
3649                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
3650                                  errmsg("cannot drop inherited column \"%s\"",
3651                                                 colName)));
3652
3653         ReleaseSysCache(tuple);
3654
3655         /*
3656          * Propagate to children as appropriate.  Unlike most other ALTER
3657          * routines, we have to do this one level of recursion at a time; we can't
3658          * use find_all_inheritors to do it in one pass.
3659          */
3660         children = find_inheritance_children(RelationGetRelid(rel));
3661
3662         if (children)
3663         {
3664                 Relation        attr_rel;
3665                 ListCell   *child;
3666
3667                 attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
3668                 foreach(child, children)
3669                 {
3670                         Oid                     childrelid = lfirst_oid(child);
3671                         Relation        childrel;
3672                         Form_pg_attribute childatt;
3673
3674                         childrel = heap_open(childrelid, AccessExclusiveLock);
3675
3676                         tuple = SearchSysCacheCopyAttName(childrelid, colName);
3677                         if (!HeapTupleIsValid(tuple))           /* shouldn't happen */
3678                                 elog(ERROR, "cache lookup failed for attribute \"%s\" of relation %u",
3679                                          colName, childrelid);
3680                         childatt = (Form_pg_attribute) GETSTRUCT(tuple);
3681
3682                         if (childatt->attinhcount <= 0)         /* shouldn't happen */
3683                                 elog(ERROR, "relation %u has non-inherited attribute \"%s\"",
3684                                          childrelid, colName);
3685
3686                         if (recurse)
3687                         {
3688                                 /*
3689                                  * If the child column has other definition sources, just
3690                                  * decrement its inheritance count; if not, recurse to delete
3691                                  * it.
3692                                  */
3693                                 if (childatt->attinhcount == 1 && !childatt->attislocal)
3694                                 {
3695                                         /* Time to delete this child column, too */
3696                                         ATExecDropColumn(childrel, colName, behavior, true, true);
3697                                 }
3698                                 else
3699                                 {
3700                                         /* Child column must survive my deletion */
3701                                         childatt->attinhcount--;
3702
3703                                         simple_heap_update(attr_rel, &tuple->t_self, tuple);
3704
3705                                         /* keep the system catalog indexes current */
3706                                         CatalogUpdateIndexes(attr_rel, tuple);
3707
3708                                         /* Make update visible */
3709                                         CommandCounterIncrement();
3710                                 }
3711                         }
3712                         else
3713                         {
3714                                 /*
3715                                  * If we were told to drop ONLY in this table (no recursion),
3716                                  * we need to mark the inheritors' attribute as locally
3717                                  * defined rather than inherited.
3718                                  */
3719                                 childatt->attinhcount--;
3720                                 childatt->attislocal = true;
3721
3722                                 simple_heap_update(attr_rel, &tuple->t_self, tuple);
3723
3724                                 /* keep the system catalog indexes current */
3725                                 CatalogUpdateIndexes(attr_rel, tuple);
3726
3727                                 /* Make update visible */
3728                                 CommandCounterIncrement();
3729                         }
3730
3731                         heap_freetuple(tuple);
3732
3733                         heap_close(childrel, NoLock);
3734                 }
3735                 heap_close(attr_rel, RowExclusiveLock);
3736         }
3737
3738         /*
3739          * Perform the actual column deletion
3740          */
3741         object.classId = RelationRelationId;
3742         object.objectId = RelationGetRelid(rel);
3743         object.objectSubId = attnum;
3744
3745         performDeletion(&object, behavior);
3746
3747         /*
3748          * If we dropped the OID column, must adjust pg_class.relhasoids
3749          */
3750         if (attnum == ObjectIdAttributeNumber)
3751         {
3752                 Relation        class_rel;
3753                 Form_pg_class tuple_class;
3754
3755                 class_rel = heap_open(RelationRelationId, RowExclusiveLock);
3756
3757                 tuple = SearchSysCacheCopy(RELOID,
3758                                                                    ObjectIdGetDatum(RelationGetRelid(rel)),
3759                                                                    0, 0, 0);
3760                 if (!HeapTupleIsValid(tuple))
3761                         elog(ERROR, "cache lookup failed for relation %u",
3762                                  RelationGetRelid(rel));
3763                 tuple_class = (Form_pg_class) GETSTRUCT(tuple);
3764
3765                 tuple_class->relhasoids = false;
3766                 simple_heap_update(class_rel, &tuple->t_self, tuple);
3767
3768                 /* Keep the catalog indexes up to date */
3769                 CatalogUpdateIndexes(class_rel, tuple);
3770
3771                 heap_close(class_rel, RowExclusiveLock);
3772         }
3773 }
3774
3775 /*
3776  * ALTER TABLE ADD INDEX
3777  *
3778  * There is no such command in the grammar, but the parser converts UNIQUE
3779  * and PRIMARY KEY constraints into AT_AddIndex subcommands.  This lets us
3780  * schedule creation of the index at the appropriate time during ALTER.
3781  */
3782 static void
3783 ATExecAddIndex(AlteredTableInfo *tab, Relation rel,
3784                            IndexStmt *stmt, bool is_rebuild)
3785 {
3786         bool            check_rights;
3787         bool            skip_build;
3788         bool            quiet;
3789
3790         Assert(IsA(stmt, IndexStmt));
3791
3792         /* suppress schema rights check when rebuilding existing index */
3793         check_rights = !is_rebuild;
3794         /* skip index build if phase 3 will have to rewrite table anyway */
3795         skip_build = (tab->newvals != NIL);
3796         /* suppress notices when rebuilding existing index */
3797         quiet = is_rebuild;
3798
3799         DefineIndex(stmt->relation, /* relation */
3800                                 stmt->idxname,  /* index name */
3801                                 InvalidOid,             /* no predefined OID */
3802                                 stmt->accessMethod,             /* am name */
3803                                 stmt->tableSpace,
3804                                 stmt->indexParams,              /* parameters */
3805                                 (Expr *) stmt->whereClause,
3806                                 stmt->rangetable,
3807                                 stmt->unique,
3808                                 stmt->primary,
3809                                 stmt->isconstraint,
3810                                 true,                   /* is_alter_table */
3811                                 check_rights,
3812                                 skip_build,
3813                                 quiet);
3814 }
3815
3816 /*
3817  * ALTER TABLE ADD CONSTRAINT
3818  */
3819 static void
3820 ATExecAddConstraint(AlteredTableInfo *tab, Relation rel, Node *newConstraint)
3821 {
3822         switch (nodeTag(newConstraint))
3823         {
3824                 case T_Constraint:
3825                         {
3826                                 Constraint *constr = (Constraint *) newConstraint;
3827
3828                                 /*
3829                                  * Currently, we only expect to see CONSTR_CHECK nodes
3830                                  * arriving here (see the preprocessing done in
3831                                  * parser/analyze.c).  Use a switch anyway to make it easier
3832                                  * to add more code later.
3833                                  */
3834                                 switch (constr->contype)
3835                                 {
3836                                         case CONSTR_CHECK:
3837                                                 {
3838                                                         List       *newcons;
3839                                                         ListCell   *lcon;
3840
3841                                                         /*
3842                                                          * Call AddRelationRawConstraints to do the work.
3843                                                          * It returns a list of cooked constraints.
3844                                                          */
3845                                                         newcons = AddRelationRawConstraints(rel, NIL,
3846                                                                                                                  list_make1(constr));
3847                                                         /* Add each constraint to Phase 3's queue */
3848                                                         foreach(lcon, newcons)
3849                                                         {
3850                                                                 CookedConstraint *ccon = (CookedConstraint *) lfirst(lcon);
3851                                                                 NewConstraint *newcon;
3852
3853                                                                 newcon = (NewConstraint *) palloc0(sizeof(NewConstraint));
3854                                                                 newcon->name = ccon->name;
3855                                                                 newcon->contype = ccon->contype;
3856                                                                 newcon->attnum = ccon->attnum;
3857                                                                 /* ExecQual wants implicit-AND format */
3858                                                                 newcon->qual = (Node *)
3859                                                                         make_ands_implicit((Expr *) ccon->expr);
3860
3861                                                                 tab->constraints = lappend(tab->constraints,
3862                                                                                                                    newcon);
3863                                                         }
3864                                                         break;
3865                                                 }
3866                                         default:
3867                                                 elog(ERROR, "unrecognized constraint type: %d",
3868                                                          (int) constr->contype);
3869                                 }
3870                                 break;
3871                         }
3872                 case T_FkConstraint:
3873                         {
3874                                 FkConstraint *fkconstraint = (FkConstraint *) newConstraint;
3875
3876                                 /*
3877                                  * Assign or validate constraint name
3878                                  */
3879                                 if (fkconstraint->constr_name)
3880                                 {
3881                                         if (ConstraintNameIsUsed(CONSTRAINT_RELATION,
3882                                                                                          RelationGetRelid(rel),
3883                                                                                          RelationGetNamespace(rel),
3884                                                                                          fkconstraint->constr_name))
3885                                                 ereport(ERROR,
3886                                                                 (errcode(ERRCODE_DUPLICATE_OBJECT),
3887                                                                  errmsg("constraint \"%s\" for relation \"%s\" already exists",
3888                                                                                 fkconstraint->constr_name,
3889                                                                                 RelationGetRelationName(rel))));
3890                                 }
3891                                 else
3892                                         fkconstraint->constr_name =
3893                                                 ChooseConstraintName(RelationGetRelationName(rel),
3894                                                                         strVal(linitial(fkconstraint->fk_attrs)),
3895                                                                                          "fkey",
3896                                                                                          RelationGetNamespace(rel),
3897                                                                                          NIL);
3898
3899                                 ATAddForeignKeyConstraint(tab, rel, fkconstraint);
3900
3901                                 break;
3902                         }
3903                 default:
3904                         elog(ERROR, "unrecognized node type: %d",
3905                                  (int) nodeTag(newConstraint));
3906         }
3907 }
3908
3909 /*
3910  * Add a foreign-key constraint to a single table
3911  *
3912  * Subroutine for ATExecAddConstraint.  Must already hold exclusive
3913  * lock on the rel, and have done appropriate validity/permissions checks
3914  * for it.
3915  */
3916 static void
3917 ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel,
3918                                                   FkConstraint *fkconstraint)
3919 {
3920         Relation        pkrel;
3921         AclResult       aclresult;
3922         int16           pkattnum[INDEX_MAX_KEYS];
3923         int16           fkattnum[INDEX_MAX_KEYS];
3924         Oid                     pktypoid[INDEX_MAX_KEYS];
3925         Oid                     fktypoid[INDEX_MAX_KEYS];
3926         Oid                     opclasses[INDEX_MAX_KEYS];
3927         int                     i;
3928         int                     numfks,
3929                                 numpks;
3930         Oid                     indexOid;
3931         Oid                     constrOid;
3932
3933         /*
3934          * Grab an exclusive lock on the pk table, so that someone doesn't delete
3935          * rows out from under us. (Although a lesser lock would do for that
3936          * purpose, we'll need exclusive lock anyway to add triggers to the pk
3937          * table; trying to start with a lesser lock will just create a risk of
3938          * deadlock.)
3939          */
3940         pkrel = heap_openrv(fkconstraint->pktable, AccessExclusiveLock);
3941
3942         /*
3943          * Validity and permissions checks
3944          *
3945          * Note: REFERENCES permissions checks are redundant with CREATE TRIGGER,
3946          * but we may as well error out sooner instead of later.
3947          */
3948         if (pkrel->rd_rel->relkind != RELKIND_RELATION)
3949                 ereport(ERROR,
3950                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
3951                                  errmsg("referenced relation \"%s\" is not a table",
3952                                                 RelationGetRelationName(pkrel))));
3953
3954         aclresult = pg_class_aclcheck(RelationGetRelid(pkrel), GetUserId(),
3955                                                                   ACL_REFERENCES);
3956         if (aclresult != ACLCHECK_OK)
3957                 aclcheck_error(aclresult, ACL_KIND_CLASS,
3958                                            RelationGetRelationName(pkrel));
3959
3960         if (!allowSystemTableMods && IsSystemRelation(pkrel))
3961                 ereport(ERROR,
3962                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
3963                                  errmsg("permission denied: \"%s\" is a system catalog",
3964                                                 RelationGetRelationName(pkrel))));
3965
3966         aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
3967                                                                   ACL_REFERENCES);
3968         if (aclresult != ACLCHECK_OK)
3969                 aclcheck_error(aclresult, ACL_KIND_CLASS,
3970                                            RelationGetRelationName(rel));
3971
3972         /*
3973          * Disallow reference from permanent table to temp table or vice versa.
3974          * (The ban on perm->temp is for fairly obvious reasons.  The ban on
3975          * temp->perm is because other backends might need to run the RI triggers
3976          * on the perm table, but they can't reliably see tuples the owning
3977          * backend has created in the temp table, because non-shared buffers are
3978          * used for temp tables.)
3979          */
3980         if (isTempNamespace(RelationGetNamespace(pkrel)))
3981         {
3982                 if (!isTempNamespace(RelationGetNamespace(rel)))
3983                         ereport(ERROR,
3984                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
3985                                          errmsg("cannot reference temporary table from permanent table constraint")));
3986         }
3987         else
3988         {
3989                 if (isTempNamespace(RelationGetNamespace(rel)))
3990                         ereport(ERROR,
3991                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
3992                                          errmsg("cannot reference permanent table from temporary table constraint")));
3993         }
3994
3995         /*
3996          * Look up the referencing attributes to make sure they exist, and record
3997          * their attnums and type OIDs.
3998          */
3999         MemSet(pkattnum, 0, sizeof(pkattnum));
4000         MemSet(fkattnum, 0, sizeof(fkattnum));
4001         MemSet(pktypoid, 0, sizeof(pktypoid));
4002         MemSet(fktypoid, 0, sizeof(fktypoid));
4003         MemSet(opclasses, 0, sizeof(opclasses));
4004
4005         numfks = transformColumnNameList(RelationGetRelid(rel),
4006                                                                          fkconstraint->fk_attrs,
4007                                                                          fkattnum, fktypoid);
4008
4009         /*
4010          * If the attribute list for the referenced table was omitted, lookup the
4011          * definition of the primary key and use it.  Otherwise, validate the
4012          * supplied attribute list.  In either case, discover the index OID and
4013          * index opclasses, and the attnums and type OIDs of the attributes.
4014          */
4015         if (fkconstraint->pk_attrs == NIL)
4016         {
4017                 numpks = transformFkeyGetPrimaryKey(pkrel, &indexOid,
4018                                                                                         &fkconstraint->pk_attrs,
4019                                                                                         pkattnum, pktypoid,
4020                                                                                         opclasses);
4021         }
4022         else
4023         {
4024                 numpks = transformColumnNameList(RelationGetRelid(pkrel),
4025                                                                                  fkconstraint->pk_attrs,
4026                                                                                  pkattnum, pktypoid);
4027                 /* Look for an index matching the column list */
4028                 indexOid = transformFkeyCheckAttrs(pkrel, numpks, pkattnum,
4029                                                                                    opclasses);
4030         }
4031
4032         /* Be sure referencing and referenced column types are comparable */
4033         if (numfks != numpks)
4034                 ereport(ERROR,
4035                                 (errcode(ERRCODE_INVALID_FOREIGN_KEY),
4036                                  errmsg("number of referencing and referenced columns for foreign key disagree")));
4037
4038         for (i = 0; i < numpks; i++)
4039         {
4040                 /*
4041                  * pktypoid[i] is the primary key table's i'th key's type fktypoid[i]
4042                  * is the foreign key table's i'th key's type
4043                  *
4044                  * Note that we look for an operator with the PK type on the left;
4045                  * when the types are different this is critical because the PK index
4046                  * will need operators with the indexkey on the left. (Ordinarily both
4047                  * commutator operators will exist if either does, but we won't get
4048                  * the right answer from the test below on opclass membership unless
4049                  * we select the proper operator.)
4050                  */
4051                 Operator        o = oper(NULL, list_make1(makeString("=")),
4052                                                          pktypoid[i], fktypoid[i],
4053                                                          true, -1);
4054
4055                 if (o == NULL)
4056                         ereport(ERROR,
4057                                         (errcode(ERRCODE_UNDEFINED_FUNCTION),
4058                                          errmsg("foreign key constraint \"%s\" "
4059                                                         "cannot be implemented",
4060                                                         fkconstraint->constr_name),
4061                                          errdetail("Key columns \"%s\" and \"%s\" "
4062                                                            "are of incompatible types: %s and %s.",
4063                                                            strVal(list_nth(fkconstraint->fk_attrs, i)),
4064                                                            strVal(list_nth(fkconstraint->pk_attrs, i)),
4065                                                            format_type_be(fktypoid[i]),
4066                                                            format_type_be(pktypoid[i]))));
4067
4068                 /*
4069                  * Check that the found operator is compatible with the PK index, and
4070                  * generate a warning if not, since otherwise costly seqscans will be
4071                  * incurred to check FK validity.
4072                  */
4073                 if (!op_in_opclass(oprid(o), opclasses[i]))
4074                         ereport(WARNING,
4075                                         (errmsg("foreign key constraint \"%s\" "
4076                                                         "will require costly sequential scans",
4077                                                         fkconstraint->constr_name),
4078                                          errdetail("Key columns \"%s\" and \"%s\" "
4079                                                            "are of different types: %s and %s.",
4080                                                            strVal(list_nth(fkconstraint->fk_attrs, i)),
4081                                                            strVal(list_nth(fkconstraint->pk_attrs, i)),
4082                                                            format_type_be(fktypoid[i]),
4083                                                            format_type_be(pktypoid[i]))));
4084
4085                 ReleaseSysCache(o);
4086         }
4087
4088         /*
4089          * Tell Phase 3 to check that the constraint is satisfied by existing rows
4090          * (we can skip this during table creation).
4091          */
4092         if (!fkconstraint->skip_validation)
4093         {
4094                 NewConstraint *newcon;
4095
4096                 newcon = (NewConstraint *) palloc0(sizeof(NewConstraint));
4097                 newcon->name = fkconstraint->constr_name;
4098                 newcon->contype = CONSTR_FOREIGN;
4099                 newcon->refrelid = RelationGetRelid(pkrel);
4100                 newcon->qual = (Node *) fkconstraint;
4101
4102                 tab->constraints = lappend(tab->constraints, newcon);
4103         }
4104
4105         /*
4106          * Record the FK constraint in pg_constraint.
4107          */
4108         constrOid = CreateConstraintEntry(fkconstraint->constr_name,
4109                                                                           RelationGetNamespace(rel),
4110                                                                           CONSTRAINT_FOREIGN,
4111                                                                           fkconstraint->deferrable,
4112                                                                           fkconstraint->initdeferred,
4113                                                                           RelationGetRelid(rel),
4114                                                                           fkattnum,
4115                                                                           numfks,
4116                                                                           InvalidOid,           /* not a domain
4117                                                                                                                  * constraint */
4118                                                                           RelationGetRelid(pkrel),
4119                                                                           pkattnum,
4120                                                                           numpks,
4121                                                                           fkconstraint->fk_upd_action,
4122                                                                           fkconstraint->fk_del_action,
4123                                                                           fkconstraint->fk_matchtype,
4124                                                                           indexOid,
4125                                                                           NULL,         /* no check constraint */
4126                                                                           NULL,
4127                                                                           NULL);
4128
4129         /*
4130          * Create the triggers that will enforce the constraint.
4131          */
4132         createForeignKeyTriggers(rel, fkconstraint, constrOid);
4133
4134         /*
4135          * Close pk table, but keep lock until we've committed.
4136          */
4137         heap_close(pkrel, NoLock);
4138 }
4139
4140
4141 /*
4142  * transformColumnNameList - transform list of column names
4143  *
4144  * Lookup each name and return its attnum and type OID
4145  */
4146 static int
4147 transformColumnNameList(Oid relId, List *colList,
4148                                                 int16 *attnums, Oid *atttypids)
4149 {
4150         ListCell   *l;
4151         int                     attnum;
4152
4153         attnum = 0;
4154         foreach(l, colList)
4155         {
4156                 char       *attname = strVal(lfirst(l));
4157                 HeapTuple       atttuple;
4158
4159                 atttuple = SearchSysCacheAttName(relId, attname);
4160                 if (!HeapTupleIsValid(atttuple))
4161                         ereport(ERROR,
4162                                         (errcode(ERRCODE_UNDEFINED_COLUMN),
4163                                          errmsg("column \"%s\" referenced in foreign key constraint does not exist",
4164                                                         attname)));
4165                 if (attnum >= INDEX_MAX_KEYS)
4166                         ereport(ERROR,
4167                                         (errcode(ERRCODE_TOO_MANY_COLUMNS),
4168                                          errmsg("cannot have more than %d keys in a foreign key",
4169                                                         INDEX_MAX_KEYS)));
4170                 attnums[attnum] = ((Form_pg_attribute) GETSTRUCT(atttuple))->attnum;
4171                 atttypids[attnum] = ((Form_pg_attribute) GETSTRUCT(atttuple))->atttypid;
4172                 ReleaseSysCache(atttuple);
4173                 attnum++;
4174         }
4175
4176         return attnum;
4177 }
4178
4179 /*
4180  * transformFkeyGetPrimaryKey -
4181  *
4182  *      Look up the names, attnums, and types of the primary key attributes
4183  *      for the pkrel.  Also return the index OID and index opclasses of the
4184  *      index supporting the primary key.
4185  *
4186  *      All parameters except pkrel are output parameters.      Also, the function
4187  *      return value is the number of attributes in the primary key.
4188  *
4189  *      Used when the column list in the REFERENCES specification is omitted.
4190  */
4191 static int
4192 transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
4193                                                    List **attnamelist,
4194                                                    int16 *attnums, Oid *atttypids,
4195                                                    Oid *opclasses)
4196 {
4197         List       *indexoidlist;
4198         ListCell   *indexoidscan;
4199         HeapTuple       indexTuple = NULL;
4200         Form_pg_index indexStruct = NULL;
4201         Datum           indclassDatum;
4202         bool            isnull;
4203         oidvector  *indclass;
4204         int                     i;
4205
4206         /*
4207          * Get the list of index OIDs for the table from the relcache, and look up
4208          * each one in the pg_index syscache until we find one marked primary key
4209          * (hopefully there isn't more than one such).
4210          */
4211         *indexOid = InvalidOid;
4212
4213         indexoidlist = RelationGetIndexList(pkrel);
4214
4215         foreach(indexoidscan, indexoidlist)
4216         {
4217                 Oid                     indexoid = lfirst_oid(indexoidscan);
4218
4219                 indexTuple = SearchSysCache(INDEXRELID,
4220                                                                         ObjectIdGetDatum(indexoid),
4221                                                                         0, 0, 0);
4222                 if (!HeapTupleIsValid(indexTuple))
4223                         elog(ERROR, "cache lookup failed for index %u", indexoid);
4224                 indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
4225                 if (indexStruct->indisprimary)
4226                 {
4227                         *indexOid = indexoid;
4228                         break;
4229                 }
4230                 ReleaseSysCache(indexTuple);
4231         }
4232
4233         list_free(indexoidlist);
4234
4235         /*
4236          * Check that we found it
4237          */
4238         if (!OidIsValid(*indexOid))
4239                 ereport(ERROR,
4240                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
4241                                  errmsg("there is no primary key for referenced table \"%s\"",
4242                                                 RelationGetRelationName(pkrel))));
4243
4244         /* Must get indclass the hard way */
4245         indclassDatum = SysCacheGetAttr(INDEXRELID, indexTuple,
4246                                                                         Anum_pg_index_indclass, &isnull);
4247         Assert(!isnull);
4248         indclass = (oidvector *) DatumGetPointer(indclassDatum);
4249
4250         /*
4251          * Now build the list of PK attributes from the indkey definition (we
4252          * assume a primary key cannot have expressional elements)
4253          */
4254         *attnamelist = NIL;
4255         for (i = 0; i < indexStruct->indnatts; i++)
4256         {
4257                 int                     pkattno = indexStruct->indkey.values[i];
4258
4259                 attnums[i] = pkattno;
4260                 atttypids[i] = attnumTypeId(pkrel, pkattno);
4261                 opclasses[i] = indclass->values[i];
4262                 *attnamelist = lappend(*attnamelist,
4263                            makeString(pstrdup(NameStr(*attnumAttName(pkrel, pkattno)))));
4264         }
4265
4266         ReleaseSysCache(indexTuple);
4267
4268         return i;
4269 }
4270
4271 /*
4272  * transformFkeyCheckAttrs -
4273  *
4274  *      Make sure that the attributes of a referenced table belong to a unique
4275  *      (or primary key) constraint.  Return the OID of the index supporting
4276  *      the constraint, as well as the opclasses associated with the index
4277  *      columns.
4278  */
4279 static Oid
4280 transformFkeyCheckAttrs(Relation pkrel,
4281                                                 int numattrs, int16 *attnums,
4282                                                 Oid *opclasses) /* output parameter */
4283 {
4284         Oid                     indexoid = InvalidOid;
4285         bool            found = false;
4286         List       *indexoidlist;
4287         ListCell   *indexoidscan;
4288
4289         /*
4290          * Get the list of index OIDs for the table from the relcache, and look up
4291          * each one in the pg_index syscache, and match unique indexes to the list
4292          * of attnums we are given.
4293          */
4294         indexoidlist = RelationGetIndexList(pkrel);
4295
4296         foreach(indexoidscan, indexoidlist)
4297         {
4298                 HeapTuple       indexTuple;
4299                 Form_pg_index indexStruct;
4300                 int                     i,
4301                                         j;
4302
4303                 indexoid = lfirst_oid(indexoidscan);
4304                 indexTuple = SearchSysCache(INDEXRELID,
4305                                                                         ObjectIdGetDatum(indexoid),
4306                                                                         0, 0, 0);
4307                 if (!HeapTupleIsValid(indexTuple))
4308                         elog(ERROR, "cache lookup failed for index %u", indexoid);
4309                 indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
4310
4311                 /*
4312                  * Must have the right number of columns; must be unique and not a
4313                  * partial index; forget it if there are any expressions, too
4314                  */
4315                 if (indexStruct->indnatts == numattrs &&
4316                         indexStruct->indisunique &&
4317                         heap_attisnull(indexTuple, Anum_pg_index_indpred) &&
4318                         heap_attisnull(indexTuple, Anum_pg_index_indexprs))
4319                 {
4320                         /* Must get indclass the hard way */
4321                         Datum           indclassDatum;
4322                         bool            isnull;
4323                         oidvector  *indclass;
4324
4325                         indclassDatum = SysCacheGetAttr(INDEXRELID, indexTuple,
4326                                                                                         Anum_pg_index_indclass, &isnull);
4327                         Assert(!isnull);
4328                         indclass = (oidvector *) DatumGetPointer(indclassDatum);
4329
4330                         /*
4331                          * The given attnum list may match the index columns in any order.
4332                          * Check that each list is a subset of the other.
4333                          */
4334                         for (i = 0; i < numattrs; i++)
4335                         {
4336                                 found = false;
4337                                 for (j = 0; j < numattrs; j++)
4338                                 {
4339                                         if (attnums[i] == indexStruct->indkey.values[j])
4340                                         {
4341                                                 found = true;
4342                                                 break;
4343                                         }
4344                                 }
4345                                 if (!found)
4346                                         break;
4347                         }
4348                         if (found)
4349                         {
4350                                 for (i = 0; i < numattrs; i++)
4351                                 {
4352                                         found = false;
4353                                         for (j = 0; j < numattrs; j++)
4354                                         {
4355                                                 if (attnums[j] == indexStruct->indkey.values[i])
4356                                                 {
4357                                                         opclasses[j] = indclass->values[i];
4358                                                         found = true;
4359                                                         break;
4360                                                 }
4361                                         }
4362                                         if (!found)
4363                                                 break;
4364                                 }
4365                         }
4366                 }
4367                 ReleaseSysCache(indexTuple);
4368                 if (found)
4369                         break;
4370         }
4371
4372         if (!found)
4373                 ereport(ERROR,
4374                                 (errcode(ERRCODE_INVALID_FOREIGN_KEY),
4375                                  errmsg("there is no unique constraint matching given keys for referenced table \"%s\"",
4376                                                 RelationGetRelationName(pkrel))));
4377
4378         list_free(indexoidlist);
4379
4380         return indexoid;
4381 }
4382
4383 /*
4384  * Scan the existing rows in a table to verify they meet a proposed FK
4385  * constraint.
4386  *
4387  * Caller must have opened and locked both relations.
4388  */
4389 static void
4390 validateForeignKeyConstraint(FkConstraint *fkconstraint,
4391                                                          Relation rel,
4392                                                          Relation pkrel)
4393 {
4394         HeapScanDesc scan;
4395         HeapTuple       tuple;
4396         Trigger         trig;
4397         ListCell   *list;
4398         int                     count;
4399
4400         /*
4401          * See if we can do it with a single LEFT JOIN query.  A FALSE result
4402          * indicates we must proceed with the fire-the-trigger method.
4403          */
4404         if (RI_Initial_Check(fkconstraint, rel, pkrel))
4405                 return;
4406
4407         /*
4408          * Scan through each tuple, calling RI_FKey_check_ins (insert trigger) as
4409          * if that tuple had just been inserted.  If any of those fail, it should
4410          * ereport(ERROR) and that's that.
4411          */
4412         MemSet(&trig, 0, sizeof(trig));
4413         trig.tgoid = InvalidOid;
4414         trig.tgname = fkconstraint->constr_name;
4415         trig.tgenabled = TRUE;
4416         trig.tgisconstraint = TRUE;
4417         trig.tgconstrrelid = RelationGetRelid(pkrel);
4418         trig.tgdeferrable = FALSE;
4419         trig.tginitdeferred = FALSE;
4420
4421         trig.tgargs = (char **) palloc(sizeof(char *) *
4422                                                                    (4 + list_length(fkconstraint->fk_attrs)
4423                                                                         + list_length(fkconstraint->pk_attrs)));
4424
4425         trig.tgargs[0] = trig.tgname;
4426         trig.tgargs[1] = RelationGetRelationName(rel);
4427         trig.tgargs[2] = RelationGetRelationName(pkrel);
4428         trig.tgargs[3] = fkMatchTypeToString(fkconstraint->fk_matchtype);
4429         count = 4;
4430         foreach(list, fkconstraint->fk_attrs)
4431         {
4432                 char       *fk_at = strVal(lfirst(list));
4433
4434                 trig.tgargs[count] = fk_at;
4435                 count += 2;
4436         }
4437         count = 5;
4438         foreach(list, fkconstraint->pk_attrs)
4439         {
4440                 char       *pk_at = strVal(lfirst(list));
4441
4442                 trig.tgargs[count] = pk_at;
4443                 count += 2;
4444         }
4445         trig.tgnargs = count - 1;
4446
4447         scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
4448
4449         while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
4450         {
4451                 FunctionCallInfoData fcinfo;
4452                 TriggerData trigdata;
4453
4454                 /*
4455                  * Make a call to the trigger function
4456                  *
4457                  * No parameters are passed, but we do set a context
4458                  */
4459                 MemSet(&fcinfo, 0, sizeof(fcinfo));
4460
4461                 /*
4462                  * We assume RI_FKey_check_ins won't look at flinfo...
4463                  */
4464                 trigdata.type = T_TriggerData;
4465                 trigdata.tg_event = TRIGGER_EVENT_INSERT | TRIGGER_EVENT_ROW;
4466                 trigdata.tg_relation = rel;
4467                 trigdata.tg_trigtuple = tuple;
4468                 trigdata.tg_newtuple = NULL;
4469                 trigdata.tg_trigger = &trig;
4470                 trigdata.tg_trigtuplebuf = scan->rs_cbuf;
4471                 trigdata.tg_newtuplebuf = InvalidBuffer;
4472
4473                 fcinfo.context = (Node *) &trigdata;
4474
4475                 RI_FKey_check_ins(&fcinfo);
4476         }
4477
4478         heap_endscan(scan);
4479
4480         pfree(trig.tgargs);
4481 }
4482
4483 static void
4484 CreateFKCheckTrigger(RangeVar *myRel, FkConstraint *fkconstraint,
4485                                          ObjectAddress *constrobj, ObjectAddress *trigobj,
4486                                          bool on_insert)
4487 {
4488         CreateTrigStmt *fk_trigger;
4489         ListCell   *fk_attr;
4490         ListCell   *pk_attr;
4491
4492         fk_trigger = makeNode(CreateTrigStmt);
4493         fk_trigger->trigname = fkconstraint->constr_name;
4494         fk_trigger->relation = myRel;
4495         fk_trigger->before = false;
4496         fk_trigger->row = true;
4497
4498         /* Either ON INSERT or ON UPDATE */
4499         if (on_insert)
4500         {
4501                 fk_trigger->funcname = SystemFuncName("RI_FKey_check_ins");
4502                 fk_trigger->actions[0] = 'i';
4503         }
4504         else
4505         {
4506                 fk_trigger->funcname = SystemFuncName("RI_FKey_check_upd");
4507                 fk_trigger->actions[0] = 'u';
4508         }
4509         fk_trigger->actions[1] = '\0';
4510
4511         fk_trigger->isconstraint = true;
4512         fk_trigger->deferrable = fkconstraint->deferrable;
4513         fk_trigger->initdeferred = fkconstraint->initdeferred;
4514         fk_trigger->constrrel = fkconstraint->pktable;
4515
4516         fk_trigger->args = NIL;
4517         fk_trigger->args = lappend(fk_trigger->args,
4518                                                            makeString(fkconstraint->constr_name));
4519         fk_trigger->args = lappend(fk_trigger->args,
4520                                                            makeString(myRel->relname));
4521         fk_trigger->args = lappend(fk_trigger->args,
4522                                                            makeString(fkconstraint->pktable->relname));
4523         fk_trigger->args = lappend(fk_trigger->args,
4524                                 makeString(fkMatchTypeToString(fkconstraint->fk_matchtype)));
4525         if (list_length(fkconstraint->fk_attrs) != list_length(fkconstraint->pk_attrs))
4526                 ereport(ERROR,
4527                                 (errcode(ERRCODE_INVALID_FOREIGN_KEY),
4528                                  errmsg("number of referencing and referenced columns for foreign key disagree")));
4529
4530         forboth(fk_attr, fkconstraint->fk_attrs,
4531                         pk_attr, fkconstraint->pk_attrs)
4532         {
4533                 fk_trigger->args = lappend(fk_trigger->args, lfirst(fk_attr));
4534                 fk_trigger->args = lappend(fk_trigger->args, lfirst(pk_attr));
4535         }
4536
4537         trigobj->objectId = CreateTrigger(fk_trigger, true);
4538
4539         /* Register dependency from trigger to constraint */
4540         recordDependencyOn(trigobj, constrobj, DEPENDENCY_INTERNAL);
4541
4542         /* Make changes-so-far visible */
4543         CommandCounterIncrement();
4544 }
4545
4546 /*
4547  * Create the triggers that implement an FK constraint.
4548  */
4549 static void
4550 createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
4551                                                  Oid constrOid)
4552 {
4553         RangeVar   *myRel;
4554         CreateTrigStmt *fk_trigger;
4555         ListCell   *fk_attr;
4556         ListCell   *pk_attr;
4557         ObjectAddress trigobj,
4558                                 constrobj;
4559
4560         /*
4561          * Reconstruct a RangeVar for my relation (not passed in, unfortunately).
4562          */
4563         myRel = makeRangeVar(get_namespace_name(RelationGetNamespace(rel)),
4564                                                  pstrdup(RelationGetRelationName(rel)));
4565
4566         /*
4567          * Preset objectAddress fields
4568          */
4569         constrobj.classId = ConstraintRelationId;
4570         constrobj.objectId = constrOid;
4571         constrobj.objectSubId = 0;
4572         trigobj.classId = TriggerRelationId;
4573         trigobj.objectSubId = 0;
4574
4575         /* Make changes-so-far visible */
4576         CommandCounterIncrement();
4577
4578         /*
4579          * Build and execute a CREATE CONSTRAINT TRIGGER statement for the CHECK
4580          * action for both INSERTs and UPDATEs on the referencing table.
4581          */
4582         CreateFKCheckTrigger(myRel, fkconstraint, &constrobj, &trigobj, true);
4583         CreateFKCheckTrigger(myRel, fkconstraint, &constrobj, &trigobj, false);
4584
4585         /*
4586          * Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON
4587          * DELETE action on the referenced table.
4588          */
4589         fk_trigger = makeNode(CreateTrigStmt);
4590         fk_trigger->trigname = fkconstraint->constr_name;
4591         fk_trigger->relation = fkconstraint->pktable;
4592         fk_trigger->before = false;
4593         fk_trigger->row = true;
4594         fk_trigger->actions[0] = 'd';
4595         fk_trigger->actions[1] = '\0';
4596
4597         fk_trigger->isconstraint = true;
4598         fk_trigger->constrrel = myRel;
4599         switch (fkconstraint->fk_del_action)
4600         {
4601                 case FKCONSTR_ACTION_NOACTION:
4602                         fk_trigger->deferrable = fkconstraint->deferrable;
4603                         fk_trigger->initdeferred = fkconstraint->initdeferred;
4604                         fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_del");
4605                         break;
4606                 case FKCONSTR_ACTION_RESTRICT:
4607                         fk_trigger->deferrable = false;
4608                         fk_trigger->initdeferred = false;
4609                         fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_del");
4610                         break;
4611                 case FKCONSTR_ACTION_CASCADE:
4612                         fk_trigger->deferrable = false;
4613                         fk_trigger->initdeferred = false;
4614                         fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_del");
4615                         break;
4616                 case FKCONSTR_ACTION_SETNULL:
4617                         fk_trigger->deferrable = false;
4618                         fk_trigger->initdeferred = false;
4619                         fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_del");
4620                         break;
4621                 case FKCONSTR_ACTION_SETDEFAULT:
4622                         fk_trigger->deferrable = false;
4623                         fk_trigger->initdeferred = false;
4624                         fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_del");
4625                         break;
4626                 default:
4627                         elog(ERROR, "unrecognized FK action type: %d",
4628                                  (int) fkconstraint->fk_del_action);
4629                         break;
4630         }
4631
4632         fk_trigger->args = NIL;
4633         fk_trigger->args = lappend(fk_trigger->args,
4634                                                            makeString(fkconstraint->constr_name));
4635         fk_trigger->args = lappend(fk_trigger->args,
4636                                                            makeString(myRel->relname));
4637         fk_trigger->args = lappend(fk_trigger->args,
4638                                                            makeString(fkconstraint->pktable->relname));
4639         fk_trigger->args = lappend(fk_trigger->args,
4640                                 makeString(fkMatchTypeToString(fkconstraint->fk_matchtype)));
4641         forboth(fk_attr, fkconstraint->fk_attrs,
4642                         pk_attr, fkconstraint->pk_attrs)
4643         {
4644                 fk_trigger->args = lappend(fk_trigger->args, lfirst(fk_attr));
4645                 fk_trigger->args = lappend(fk_trigger->args, lfirst(pk_attr));
4646         }
4647
4648         trigobj.objectId = CreateTrigger(fk_trigger, true);
4649
4650         /* Register dependency from trigger to constraint */
4651         recordDependencyOn(&trigobj, &constrobj, DEPENDENCY_INTERNAL);
4652
4653         /* Make changes-so-far visible */
4654         CommandCounterIncrement();
4655
4656         /*
4657          * Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON
4658          * UPDATE action on the referenced table.
4659          */
4660         fk_trigger = makeNode(CreateTrigStmt);
4661         fk_trigger->trigname = fkconstraint->constr_name;
4662         fk_trigger->relation = fkconstraint->pktable;
4663         fk_trigger->before = false;
4664         fk_trigger->row = true;
4665         fk_trigger->actions[0] = 'u';
4666         fk_trigger->actions[1] = '\0';
4667         fk_trigger->isconstraint = true;
4668         fk_trigger->constrrel = myRel;
4669         switch (fkconstraint->fk_upd_action)
4670         {
4671                 case FKCONSTR_ACTION_NOACTION:
4672                         fk_trigger->deferrable = fkconstraint->deferrable;
4673                         fk_trigger->initdeferred = fkconstraint->initdeferred;
4674                         fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_upd");
4675                         break;
4676                 case FKCONSTR_ACTION_RESTRICT:
4677                         fk_trigger->deferrable = false;
4678                         fk_trigger->initdeferred = false;
4679                         fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_upd");
4680                         break;
4681                 case FKCONSTR_ACTION_CASCADE:
4682                         fk_trigger->deferrable = false;
4683                         fk_trigger->initdeferred = false;
4684                         fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_upd");
4685                         break;
4686                 case FKCONSTR_ACTION_SETNULL:
4687                         fk_trigger->deferrable = false;
4688                         fk_trigger->initdeferred = false;
4689                         fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_upd");
4690                         break;
4691                 case FKCONSTR_ACTION_SETDEFAULT:
4692                         fk_trigger->deferrable = false;
4693                         fk_trigger->initdeferred = false;
4694                         fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_upd");
4695                         break;
4696                 default:
4697                         elog(ERROR, "unrecognized FK action type: %d",
4698                                  (int) fkconstraint->fk_upd_action);
4699                         break;
4700         }
4701
4702         fk_trigger->args = NIL;
4703         fk_trigger->args = lappend(fk_trigger->args,
4704                                                            makeString(fkconstraint->constr_name));
4705         fk_trigger->args = lappend(fk_trigger->args,
4706                                                            makeString(myRel->relname));
4707         fk_trigger->args = lappend(fk_trigger->args,
4708                                                            makeString(fkconstraint->pktable->relname));
4709         fk_trigger->args = lappend(fk_trigger->args,
4710                                 makeString(fkMatchTypeToString(fkconstraint->fk_matchtype)));
4711         forboth(fk_attr, fkconstraint->fk_attrs,
4712                         pk_attr, fkconstraint->pk_attrs)
4713         {
4714                 fk_trigger->args = lappend(fk_trigger->args, lfirst(fk_attr));
4715                 fk_trigger->args = lappend(fk_trigger->args, lfirst(pk_attr));
4716         }
4717
4718         trigobj.objectId = CreateTrigger(fk_trigger, true);
4719
4720         /* Register dependency from trigger to constraint */
4721         recordDependencyOn(&trigobj, &constrobj, DEPENDENCY_INTERNAL);
4722 }
4723
4724 /*
4725  * fkMatchTypeToString -
4726  *        convert FKCONSTR_MATCH_xxx code to string to use in trigger args
4727  */
4728 static char *
4729 fkMatchTypeToString(char match_type)
4730 {
4731         switch (match_type)
4732         {
4733                 case FKCONSTR_MATCH_FULL:
4734                         return pstrdup("FULL");
4735                 case FKCONSTR_MATCH_PARTIAL:
4736                         return pstrdup("PARTIAL");
4737                 case FKCONSTR_MATCH_UNSPECIFIED:
4738                         return pstrdup("UNSPECIFIED");
4739                 default:
4740                         elog(ERROR, "unrecognized match type: %d",
4741                                  (int) match_type);
4742         }
4743         return NULL;                            /* can't get here */
4744 }
4745
4746 /*
4747  * ALTER TABLE DROP CONSTRAINT
4748  */
4749 static void
4750 ATPrepDropConstraint(List **wqueue, Relation rel,
4751                                          bool recurse, AlterTableCmd *cmd)
4752 {
4753         /*
4754          * We don't want errors or noise from child tables, so we have to pass
4755          * down a modified command.
4756          */
4757         if (recurse)
4758         {
4759                 AlterTableCmd *childCmd = copyObject(cmd);
4760
4761                 childCmd->subtype = AT_DropConstraintQuietly;
4762                 ATSimpleRecursion(wqueue, rel, childCmd, recurse);
4763         }
4764 }
4765
4766 static void
4767 ATExecDropConstraint(Relation rel, const char *constrName,
4768                                          DropBehavior behavior, bool quiet)
4769 {
4770         int                     deleted;
4771
4772         deleted = RemoveRelConstraints(rel, constrName, behavior);
4773
4774         if (!quiet)
4775         {
4776                 /* If zero constraints deleted, complain */
4777                 if (deleted == 0)
4778                         ereport(ERROR,
4779                                         (errcode(ERRCODE_UNDEFINED_OBJECT),
4780                                          errmsg("constraint \"%s\" does not exist",
4781                                                         constrName)));
4782                 /* Otherwise if more than one constraint deleted, notify */
4783                 else if (deleted > 1)
4784                         ereport(NOTICE,
4785                                         (errmsg("multiple constraints named \"%s\" were dropped",
4786                                                         constrName)));
4787         }
4788 }
4789
4790 /*
4791  * ALTER COLUMN TYPE
4792  */
4793 static void
4794 ATPrepAlterColumnType(List **wqueue,
4795                                           AlteredTableInfo *tab, Relation rel,
4796                                           bool recurse, bool recursing,
4797                                           AlterTableCmd *cmd)
4798 {
4799         char       *colName = cmd->name;
4800         TypeName   *typename = (TypeName *) cmd->def;
4801         HeapTuple       tuple;
4802         Form_pg_attribute attTup;
4803         AttrNumber      attnum;
4804         Oid                     targettype;
4805         Node       *transform;
4806         NewColumnValue *newval;
4807         ParseState *pstate = make_parsestate(NULL);
4808
4809         /* lookup the attribute so we can check inheritance status */
4810         tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
4811         if (!HeapTupleIsValid(tuple))
4812                 ereport(ERROR,
4813                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
4814                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
4815                                                 colName, RelationGetRelationName(rel))));
4816         attTup = (Form_pg_attribute) GETSTRUCT(tuple);
4817         attnum = attTup->attnum;
4818
4819         /* Can't alter a system attribute */
4820         if (attnum <= 0)
4821                 ereport(ERROR,
4822                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4823                                  errmsg("cannot alter system column \"%s\"",
4824                                                 colName)));
4825
4826         /* Don't alter inherited columns */
4827         if (attTup->attinhcount > 0 && !recursing)
4828                 ereport(ERROR,
4829                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
4830                                  errmsg("cannot alter inherited column \"%s\"",
4831                                                 colName)));
4832
4833         /* Look up the target type */
4834         targettype = typenameTypeId(NULL, typename);
4835
4836         /* make sure datatype is legal for a column */
4837         CheckAttributeType(colName, targettype);
4838
4839         /*
4840          * Set up an expression to transform the old data value to the new type.
4841          * If a USING option was given, transform and use that expression, else
4842          * just take the old value and try to coerce it.  We do this first so that
4843          * type incompatibility can be detected before we waste effort, and
4844          * because we need the expression to be parsed against the original table
4845          * rowtype.
4846          */
4847         if (cmd->transform)
4848         {
4849                 RangeTblEntry *rte;
4850
4851                 /* Expression must be able to access vars of old table */
4852                 rte = addRangeTableEntryForRelation(pstate,
4853                                                                                         rel,
4854                                                                                         NULL,
4855                                                                                         false,
4856                                                                                         true);
4857                 addRTEtoQuery(pstate, rte, false, true, true);
4858
4859                 transform = transformExpr(pstate, cmd->transform);
4860
4861                 /* It can't return a set */
4862                 if (expression_returns_set(transform))
4863                         ereport(ERROR,
4864                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
4865                                          errmsg("transform expression must not return a set")));
4866
4867                 /* No subplans or aggregates, either... */
4868                 if (pstate->p_hasSubLinks)
4869                         ereport(ERROR,
4870                                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4871                                          errmsg("cannot use subquery in transform expression")));
4872                 if (pstate->p_hasAggs)
4873                         ereport(ERROR,
4874                                         (errcode(ERRCODE_GROUPING_ERROR),
4875                         errmsg("cannot use aggregate function in transform expression")));
4876         }
4877         else
4878         {
4879                 transform = (Node *) makeVar(1, attnum,
4880                                                                          attTup->atttypid, attTup->atttypmod,
4881                                                                          0);
4882         }
4883
4884         transform = coerce_to_target_type(pstate,
4885                                                                           transform, exprType(transform),
4886                                                                           targettype, typename->typmod,
4887                                                                           COERCION_ASSIGNMENT,
4888                                                                           COERCE_IMPLICIT_CAST);
4889         if (transform == NULL)
4890                 ereport(ERROR,
4891                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
4892                                  errmsg("column \"%s\" cannot be cast to type \"%s\"",
4893                                                 colName, TypeNameToString(typename))));
4894
4895         /*
4896          * Add a work queue item to make ATRewriteTable update the column
4897          * contents.
4898          */
4899         newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
4900         newval->attnum = attnum;
4901         newval->expr = (Expr *) transform;
4902
4903         tab->newvals = lappend(tab->newvals, newval);
4904
4905         ReleaseSysCache(tuple);
4906
4907         /*
4908          * The recursion case is handled by ATSimpleRecursion.  However, if we are
4909          * told not to recurse, there had better not be any child tables; else the
4910          * alter would put them out of step.
4911          */
4912         if (recurse)
4913                 ATSimpleRecursion(wqueue, rel, cmd, recurse);
4914         else if (!recursing &&
4915                          find_inheritance_children(RelationGetRelid(rel)) != NIL)
4916                 ereport(ERROR,
4917                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
4918                                  errmsg("type of inherited column \"%s\" must be changed in child tables too",
4919                                                 colName)));
4920 }
4921
4922 static void
4923 ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
4924                                           const char *colName, TypeName *typename)
4925 {
4926         HeapTuple       heapTup;
4927         Form_pg_attribute attTup;
4928         AttrNumber      attnum;
4929         HeapTuple       typeTuple;
4930         Form_pg_type tform;
4931         Oid                     targettype;
4932         Node       *defaultexpr;
4933         Relation        attrelation;
4934         Relation        depRel;
4935         ScanKeyData key[3];
4936         SysScanDesc scan;
4937         HeapTuple       depTup;
4938
4939         attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
4940
4941         /* Look up the target column */
4942         heapTup = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
4943         if (!HeapTupleIsValid(heapTup))         /* shouldn't happen */
4944                 ereport(ERROR,
4945                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
4946                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
4947                                                 colName, RelationGetRelationName(rel))));
4948         attTup = (Form_pg_attribute) GETSTRUCT(heapTup);
4949         attnum = attTup->attnum;
4950
4951         /* Check for multiple ALTER TYPE on same column --- can't cope */
4952         if (attTup->atttypid != tab->oldDesc->attrs[attnum - 1]->atttypid ||
4953                 attTup->atttypmod != tab->oldDesc->attrs[attnum - 1]->atttypmod)
4954                 ereport(ERROR,
4955                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4956                                  errmsg("cannot alter type of column \"%s\" twice",
4957                                                 colName)));
4958
4959         /* Look up the target type (should not fail, since prep found it) */
4960         typeTuple = typenameType(NULL, typename);
4961         tform = (Form_pg_type) GETSTRUCT(typeTuple);
4962         targettype = HeapTupleGetOid(typeTuple);
4963
4964         /*
4965          * If there is a default expression for the column, get it and ensure we
4966          * can coerce it to the new datatype.  (We must do this before changing
4967          * the column type, because build_column_default itself will try to
4968          * coerce, and will not issue the error message we want if it fails.)
4969          *
4970          * We remove any implicit coercion steps at the top level of the old
4971          * default expression; this has been agreed to satisfy the principle of
4972          * least surprise.      (The conversion to the new column type should act like
4973          * it started from what the user sees as the stored expression, and the
4974          * implicit coercions aren't going to be shown.)
4975          */
4976         if (attTup->atthasdef)
4977         {
4978                 defaultexpr = build_column_default(rel, attnum);
4979                 Assert(defaultexpr);
4980                 defaultexpr = strip_implicit_coercions(defaultexpr);
4981                 defaultexpr = coerce_to_target_type(NULL,               /* no UNKNOWN params */
4982                                                                                   defaultexpr, exprType(defaultexpr),
4983                                                                                         targettype, typename->typmod,
4984                                                                                         COERCION_ASSIGNMENT,
4985                                                                                         COERCE_IMPLICIT_CAST);
4986                 if (defaultexpr == NULL)
4987                         ereport(ERROR,
4988                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
4989                         errmsg("default for column \"%s\" cannot be cast to type \"%s\"",
4990                                    colName, TypeNameToString(typename))));
4991         }
4992         else
4993                 defaultexpr = NULL;
4994
4995         /*
4996          * Find everything that depends on the column (constraints, indexes, etc),
4997          * and record enough information to let us recreate the objects.
4998          *
4999          * The actual recreation does not happen here, but only after we have
5000          * performed all the individual ALTER TYPE operations.  We have to save
5001          * the info before executing ALTER TYPE, though, else the deparser will
5002          * get confused.
5003          *
5004          * There could be multiple entries for the same object, so we must check
5005          * to ensure we process each one only once.  Note: we assume that an index
5006          * that implements a constraint will not show a direct dependency on the
5007          * column.
5008          */
5009         depRel = heap_open(DependRelationId, RowExclusiveLock);
5010
5011         ScanKeyInit(&key[0],
5012                                 Anum_pg_depend_refclassid,
5013                                 BTEqualStrategyNumber, F_OIDEQ,
5014                                 ObjectIdGetDatum(RelationRelationId));
5015         ScanKeyInit(&key[1],
5016                                 Anum_pg_depend_refobjid,
5017                                 BTEqualStrategyNumber, F_OIDEQ,
5018                                 ObjectIdGetDatum(RelationGetRelid(rel)));
5019         ScanKeyInit(&key[2],
5020                                 Anum_pg_depend_refobjsubid,
5021                                 BTEqualStrategyNumber, F_INT4EQ,
5022                                 Int32GetDatum((int32) attnum));
5023
5024         scan = systable_beginscan(depRel, DependReferenceIndexId, true,
5025                                                           SnapshotNow, 3, key);
5026
5027         while (HeapTupleIsValid(depTup = systable_getnext(scan)))
5028         {
5029                 Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(depTup);
5030                 ObjectAddress foundObject;
5031
5032                 /* We don't expect any PIN dependencies on columns */
5033                 if (foundDep->deptype == DEPENDENCY_PIN)
5034                         elog(ERROR, "cannot alter type of a pinned column");
5035
5036                 foundObject.classId = foundDep->classid;
5037                 foundObject.objectId = foundDep->objid;
5038                 foundObject.objectSubId = foundDep->objsubid;
5039
5040                 switch (getObjectClass(&foundObject))
5041                 {
5042                         case OCLASS_CLASS:
5043                                 {
5044                                         char            relKind = get_rel_relkind(foundObject.objectId);
5045
5046                                         if (relKind == RELKIND_INDEX)
5047                                         {
5048                                                 Assert(foundObject.objectSubId == 0);
5049                                                 if (!list_member_oid(tab->changedIndexOids, foundObject.objectId))
5050                                                 {
5051                                                         tab->changedIndexOids = lappend_oid(tab->changedIndexOids,
5052                                                                                                            foundObject.objectId);
5053                                                         tab->changedIndexDefs = lappend(tab->changedIndexDefs,
5054                                                            pg_get_indexdef_string(foundObject.objectId));
5055                                                 }
5056                                         }
5057                                         else if (relKind == RELKIND_SEQUENCE)
5058                                         {
5059                                                 /*
5060                                                  * This must be a SERIAL column's sequence.  We need
5061                                                  * not do anything to it.
5062                                                  */
5063                                                 Assert(foundObject.objectSubId == 0);
5064                                         }
5065                                         else
5066                                         {
5067                                                 /* Not expecting any other direct dependencies... */
5068                                                 elog(ERROR, "unexpected object depending on column: %s",
5069                                                          getObjectDescription(&foundObject));
5070                                         }
5071                                         break;
5072                                 }
5073
5074                         case OCLASS_CONSTRAINT:
5075                                 Assert(foundObject.objectSubId == 0);
5076                                 if (!list_member_oid(tab->changedConstraintOids,
5077                                                                          foundObject.objectId))
5078                                 {
5079                                         char *defstring = pg_get_constraintdef_string(foundObject.objectId);
5080
5081                                         /*
5082                                          * Put NORMAL dependencies at the front of the list and
5083                                          * AUTO dependencies at the back.  This makes sure that
5084                                          * foreign-key constraints depending on this column will
5085                                          * be dropped before unique or primary-key constraints of
5086                                          * the column; which we must have because the FK
5087                                          * constraints depend on the indexes belonging to the
5088                                          * unique constraints.
5089                                          */
5090                                         if (foundDep->deptype == DEPENDENCY_NORMAL)
5091                                         {
5092                                                 tab->changedConstraintOids =
5093                                                         lcons_oid(foundObject.objectId,
5094                                                                           tab->changedConstraintOids);
5095                                                 tab->changedConstraintDefs =
5096                                                         lcons(defstring,
5097                                                                   tab->changedConstraintDefs);
5098                                         }
5099                                         else
5100                                         {
5101                                                 tab->changedConstraintOids =
5102                                                         lappend_oid(tab->changedConstraintOids,
5103                                                                                 foundObject.objectId);
5104                                                 tab->changedConstraintDefs =
5105                                                         lappend(tab->changedConstraintDefs,
5106                                                                         defstring);
5107                                         }
5108                                 }
5109                                 break;
5110
5111                         case OCLASS_REWRITE:
5112                                 /* XXX someday see if we can cope with revising views */
5113                                 ereport(ERROR,
5114                                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
5115                                                  errmsg("cannot alter type of a column used by a view or rule"),
5116                                                  errdetail("%s depends on column \"%s\"",
5117                                                                    getObjectDescription(&foundObject),
5118                                                                    colName)));
5119                                 break;
5120
5121                         case OCLASS_DEFAULT:
5122
5123                                 /*
5124                                  * Ignore the column's default expression, since we will fix
5125                                  * it below.
5126                                  */
5127                                 Assert(defaultexpr);
5128                                 break;
5129
5130                         case OCLASS_PROC:
5131                         case OCLASS_TYPE:
5132                         case OCLASS_CAST:
5133                         case OCLASS_CONVERSION:
5134                         case OCLASS_LANGUAGE:
5135                         case OCLASS_OPERATOR:
5136                         case OCLASS_OPCLASS:
5137                         case OCLASS_TRIGGER:
5138                         case OCLASS_SCHEMA:
5139
5140                                 /*
5141                                  * We don't expect any of these sorts of objects to depend on
5142                                  * a column.
5143                                  */
5144                                 elog(ERROR, "unexpected object depending on column: %s",
5145                                          getObjectDescription(&foundObject));
5146                                 break;
5147
5148                         default:
5149                                 elog(ERROR, "unrecognized object class: %u",
5150                                          foundObject.classId);
5151                 }
5152         }
5153
5154         systable_endscan(scan);
5155
5156         /*
5157          * Now scan for dependencies of this column on other things.  The only
5158          * thing we should find is the dependency on the column datatype, which we
5159          * want to remove.
5160          */
5161         ScanKeyInit(&key[0],
5162                                 Anum_pg_depend_classid,
5163                                 BTEqualStrategyNumber, F_OIDEQ,
5164                                 ObjectIdGetDatum(RelationRelationId));
5165         ScanKeyInit(&key[1],
5166                                 Anum_pg_depend_objid,
5167                                 BTEqualStrategyNumber, F_OIDEQ,
5168                                 ObjectIdGetDatum(RelationGetRelid(rel)));
5169         ScanKeyInit(&key[2],
5170                                 Anum_pg_depend_objsubid,
5171                                 BTEqualStrategyNumber, F_INT4EQ,
5172                                 Int32GetDatum((int32) attnum));
5173
5174         scan = systable_beginscan(depRel, DependDependerIndexId, true,
5175                                                           SnapshotNow, 3, key);
5176
5177         while (HeapTupleIsValid(depTup = systable_getnext(scan)))
5178         {
5179                 Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(depTup);
5180
5181                 if (foundDep->deptype != DEPENDENCY_NORMAL)
5182                         elog(ERROR, "found unexpected dependency type '%c'",
5183                                  foundDep->deptype);
5184                 if (foundDep->refclassid != TypeRelationId ||
5185                         foundDep->refobjid != attTup->atttypid)
5186                         elog(ERROR, "found unexpected dependency for column");
5187
5188                 simple_heap_delete(depRel, &depTup->t_self);
5189         }
5190
5191         systable_endscan(scan);
5192
5193         heap_close(depRel, RowExclusiveLock);
5194
5195         /*
5196          * Here we go --- change the recorded column type.      (Note heapTup is a
5197          * copy of the syscache entry, so okay to scribble on.)
5198          */
5199         attTup->atttypid = targettype;
5200         attTup->atttypmod = typename->typmod;
5201         attTup->attndims = list_length(typename->arrayBounds);
5202         attTup->attlen = tform->typlen;
5203         attTup->attbyval = tform->typbyval;
5204         attTup->attalign = tform->typalign;
5205         attTup->attstorage = tform->typstorage;
5206
5207         ReleaseSysCache(typeTuple);
5208
5209         simple_heap_update(attrelation, &heapTup->t_self, heapTup);
5210
5211         /* keep system catalog indexes current */
5212         CatalogUpdateIndexes(attrelation, heapTup);
5213
5214         heap_close(attrelation, RowExclusiveLock);
5215
5216         /* Install dependency on new datatype */
5217         add_column_datatype_dependency(RelationGetRelid(rel), attnum, targettype);
5218
5219         /*
5220          * Drop any pg_statistic entry for the column, since it's now wrong type
5221          */
5222         RemoveStatistics(RelationGetRelid(rel), attnum);
5223
5224         /*
5225          * Update the default, if present, by brute force --- remove and re-add
5226          * the default.  Probably unsafe to take shortcuts, since the new version
5227          * may well have additional dependencies.  (It's okay to do this now,
5228          * rather than after other ALTER TYPE commands, since the default won't
5229          * depend on other column types.)
5230          */
5231         if (defaultexpr)
5232         {
5233                 /* Must make new row visible since it will be updated again */
5234                 CommandCounterIncrement();
5235
5236                 /*
5237                  * We use RESTRICT here for safety, but at present we do not expect
5238                  * anything to depend on the default.
5239                  */
5240                 RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, true);
5241
5242                 StoreAttrDefault(rel, attnum, nodeToString(defaultexpr));
5243         }
5244
5245         /* Cleanup */
5246         heap_freetuple(heapTup);
5247 }
5248
5249 /*
5250  * Cleanup after we've finished all the ALTER TYPE operations for a
5251  * particular relation.  We have to drop and recreate all the indexes
5252  * and constraints that depend on the altered columns.
5253  */
5254 static void
5255 ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab)
5256 {
5257         ObjectAddress obj;
5258         ListCell   *l;
5259
5260         /*
5261          * Re-parse the index and constraint definitions, and attach them to the
5262          * appropriate work queue entries.      We do this before dropping because in
5263          * the case of a FOREIGN KEY constraint, we might not yet have exclusive
5264          * lock on the table the constraint is attached to, and we need to get
5265          * that before dropping.  It's safe because the parser won't actually look
5266          * at the catalogs to detect the existing entry.
5267          */
5268         foreach(l, tab->changedIndexDefs)
5269                 ATPostAlterTypeParse((char *) lfirst(l), wqueue);
5270         foreach(l, tab->changedConstraintDefs)
5271                 ATPostAlterTypeParse((char *) lfirst(l), wqueue);
5272
5273         /*
5274          * Now we can drop the existing constraints and indexes --- constraints
5275          * first, since some of them might depend on the indexes.  In fact, we
5276          * have to delete FOREIGN KEY constraints before UNIQUE constraints,
5277          * but we already ordered the constraint list to ensure that would happen.
5278          * It should be okay to use DROP_RESTRICT here, since nothing else should
5279          * be depending on these objects.
5280          */
5281         foreach(l, tab->changedConstraintOids)
5282         {
5283                 obj.classId = ConstraintRelationId;
5284                 obj.objectId = lfirst_oid(l);
5285                 obj.objectSubId = 0;
5286                 performDeletion(&obj, DROP_RESTRICT);
5287         }
5288
5289         foreach(l, tab->changedIndexOids)
5290         {
5291                 obj.classId = RelationRelationId;
5292                 obj.objectId = lfirst_oid(l);
5293                 obj.objectSubId = 0;
5294                 performDeletion(&obj, DROP_RESTRICT);
5295         }
5296
5297         /*
5298          * The objects will get recreated during subsequent passes over the work
5299          * queue.
5300          */
5301 }
5302
5303 static void
5304 ATPostAlterTypeParse(char *cmd, List **wqueue)
5305 {
5306         List       *raw_parsetree_list;
5307         List       *querytree_list;
5308         ListCell   *list_item;
5309
5310         /*
5311          * We expect that we only have to do raw parsing and parse analysis, not
5312          * any rule rewriting, since these will all be utility statements.
5313          */
5314         raw_parsetree_list = raw_parser(cmd);
5315         querytree_list = NIL;
5316         foreach(list_item, raw_parsetree_list)
5317         {
5318                 Node       *parsetree = (Node *) lfirst(list_item);
5319
5320                 querytree_list = list_concat(querytree_list,
5321                                                                          parse_analyze(parsetree, cmd, NULL, 0));
5322         }
5323
5324         /*
5325          * Attach each generated command to the proper place in the work queue.
5326          * Note this could result in creation of entirely new work-queue entries.
5327          */
5328         foreach(list_item, querytree_list)
5329         {
5330                 Query      *query = (Query *) lfirst(list_item);
5331                 Relation        rel;
5332                 AlteredTableInfo *tab;
5333
5334                 Assert(IsA(query, Query));
5335                 Assert(query->commandType == CMD_UTILITY);
5336                 switch (nodeTag(query->utilityStmt))
5337                 {
5338                         case T_IndexStmt:
5339                                 {
5340                                         IndexStmt  *stmt = (IndexStmt *) query->utilityStmt;
5341                                         AlterTableCmd *newcmd;
5342
5343                                         rel = relation_openrv(stmt->relation, AccessExclusiveLock);
5344                                         tab = ATGetQueueEntry(wqueue, rel);
5345                                         newcmd = makeNode(AlterTableCmd);
5346                                         newcmd->subtype = AT_ReAddIndex;
5347                                         newcmd->def = (Node *) stmt;
5348                                         tab->subcmds[AT_PASS_OLD_INDEX] =
5349                                                 lappend(tab->subcmds[AT_PASS_OLD_INDEX], newcmd);
5350                                         relation_close(rel, NoLock);
5351                                         break;
5352                                 }
5353                         case T_AlterTableStmt:
5354                                 {
5355                                         AlterTableStmt *stmt = (AlterTableStmt *) query->utilityStmt;
5356                                         ListCell   *lcmd;
5357
5358                                         rel = relation_openrv(stmt->relation, AccessExclusiveLock);
5359                                         tab = ATGetQueueEntry(wqueue, rel);
5360                                         foreach(lcmd, stmt->cmds)
5361                                         {
5362                                                 AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd);
5363
5364                                                 switch (cmd->subtype)
5365                                                 {
5366                                                         case AT_AddIndex:
5367                                                                 cmd->subtype = AT_ReAddIndex;
5368                                                                 tab->subcmds[AT_PASS_OLD_INDEX] =
5369                                                                         lappend(tab->subcmds[AT_PASS_OLD_INDEX], cmd);
5370                                                                 break;
5371                                                         case AT_AddConstraint:
5372                                                                 tab->subcmds[AT_PASS_OLD_CONSTR] =
5373                                                                         lappend(tab->subcmds[AT_PASS_OLD_CONSTR], cmd);
5374                                                                 break;
5375                                                         default:
5376                                                                 elog(ERROR, "unexpected statement type: %d",
5377                                                                          (int) cmd->subtype);
5378                                                 }
5379                                         }
5380                                         relation_close(rel, NoLock);
5381                                         break;
5382                                 }
5383                         default:
5384                                 elog(ERROR, "unexpected statement type: %d",
5385                                          (int) nodeTag(query->utilityStmt));
5386                 }
5387         }
5388 }
5389
5390
5391 /*
5392  * ALTER TABLE OWNER
5393  *
5394  * recursing is true if we are recursing from a table to its indexes or
5395  * toast table.  We don't allow the ownership of those things to be
5396  * changed separately from the parent table.  Also, we can skip permission
5397  * checks (this is necessary not just an optimization, else we'd fail to
5398  * handle toast tables properly).
5399  */
5400 void
5401 ATExecChangeOwner(Oid relationOid, Oid newOwnerId, bool recursing)
5402 {
5403         Relation        target_rel;
5404         Relation        class_rel;
5405         HeapTuple       tuple;
5406         Form_pg_class tuple_class;
5407
5408         /*
5409          * Get exclusive lock till end of transaction on the target table. Use
5410          * relation_open so that we can work on indexes and sequences.
5411          */
5412         target_rel = relation_open(relationOid, AccessExclusiveLock);
5413
5414         /* Get its pg_class tuple, too */
5415         class_rel = heap_open(RelationRelationId, RowExclusiveLock);
5416
5417         tuple = SearchSysCache(RELOID,
5418                                                    ObjectIdGetDatum(relationOid),
5419                                                    0, 0, 0);
5420         if (!HeapTupleIsValid(tuple))
5421                 elog(ERROR, "cache lookup failed for relation %u", relationOid);
5422         tuple_class = (Form_pg_class) GETSTRUCT(tuple);
5423
5424         /* Can we change the ownership of this tuple? */
5425         switch (tuple_class->relkind)
5426         {
5427                 case RELKIND_RELATION:
5428                 case RELKIND_VIEW:
5429                 case RELKIND_SEQUENCE:
5430                         /* ok to change owner */
5431                         break;
5432                 case RELKIND_INDEX:
5433                         if (!recursing)
5434                         {
5435                                 /*
5436                                  * Because ALTER INDEX OWNER used to be allowed, and in fact
5437                                  * is generated by old versions of pg_dump, we give a warning
5438                                  * and do nothing rather than erroring out.  Also, to avoid
5439                                  * unnecessary chatter while restoring those old dumps, say
5440                                  * nothing at all if the command would be a no-op anyway.
5441                                  */
5442                                 if (tuple_class->relowner != newOwnerId)
5443                                         ereport(WARNING,
5444                                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
5445                                                          errmsg("cannot change owner of index \"%s\"",
5446                                                                         NameStr(tuple_class->relname)),
5447                                                          errhint("Change the ownership of the index's table, instead.")));
5448                                 /* quick hack to exit via the no-op path */
5449                                 newOwnerId = tuple_class->relowner;
5450                         }
5451                         break;
5452                 case RELKIND_TOASTVALUE:
5453                         if (recursing)
5454                                 break;
5455                         /* FALL THRU */
5456                 default:
5457                         ereport(ERROR,
5458                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
5459                                          errmsg("\"%s\" is not a table, view, or sequence",
5460                                                         NameStr(tuple_class->relname))));
5461         }
5462
5463         /*
5464          * If the new owner is the same as the existing owner, consider the
5465          * command to have succeeded.  This is for dump restoration purposes.
5466          */
5467         if (tuple_class->relowner != newOwnerId)
5468         {
5469                 Datum           repl_val[Natts_pg_class];
5470                 char            repl_null[Natts_pg_class];
5471                 char            repl_repl[Natts_pg_class];
5472                 Acl                *newAcl;
5473                 Datum           aclDatum;
5474                 bool            isNull;
5475                 HeapTuple       newtuple;
5476
5477                 /* skip permission checks when recursing to index or toast table */
5478                 if (!recursing)
5479                 {
5480                         /* Superusers can always do it */
5481                         if (!superuser())
5482                         {
5483                                 Oid                     namespaceOid = tuple_class->relnamespace;
5484                                 AclResult       aclresult;
5485
5486                                 /* Otherwise, must be owner of the existing object */
5487                                 if (!pg_class_ownercheck(relationOid, GetUserId()))
5488                                         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
5489                                                                    RelationGetRelationName(target_rel));
5490
5491                                 /* Must be able to become new owner */
5492                                 check_is_member_of_role(GetUserId(), newOwnerId);
5493
5494                                 /* New owner must have CREATE privilege on namespace */
5495                                 aclresult = pg_namespace_aclcheck(namespaceOid, newOwnerId,
5496                                                                                                   ACL_CREATE);
5497                                 if (aclresult != ACLCHECK_OK)
5498                                         aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
5499                                                                    get_namespace_name(namespaceOid));
5500                         }
5501                 }
5502
5503                 memset(repl_null, ' ', sizeof(repl_null));
5504                 memset(repl_repl, ' ', sizeof(repl_repl));
5505
5506                 repl_repl[Anum_pg_class_relowner - 1] = 'r';
5507                 repl_val[Anum_pg_class_relowner - 1] = ObjectIdGetDatum(newOwnerId);
5508
5509                 /*
5510                  * Determine the modified ACL for the new owner.  This is only
5511                  * necessary when the ACL is non-null.
5512                  */
5513                 aclDatum = SysCacheGetAttr(RELOID, tuple,
5514                                                                    Anum_pg_class_relacl,
5515                                                                    &isNull);
5516                 if (!isNull)
5517                 {
5518                         newAcl = aclnewowner(DatumGetAclP(aclDatum),
5519                                                                  tuple_class->relowner, newOwnerId);
5520                         repl_repl[Anum_pg_class_relacl - 1] = 'r';
5521                         repl_val[Anum_pg_class_relacl - 1] = PointerGetDatum(newAcl);
5522                 }
5523
5524                 newtuple = heap_modifytuple(tuple, RelationGetDescr(class_rel), repl_val, repl_null, repl_repl);
5525
5526                 simple_heap_update(class_rel, &newtuple->t_self, newtuple);
5527                 CatalogUpdateIndexes(class_rel, newtuple);
5528
5529                 heap_freetuple(newtuple);
5530
5531                 /* Update owner dependency reference */
5532                 changeDependencyOnOwner(RelationRelationId, relationOid, newOwnerId);
5533
5534                 /*
5535                  * Also change the ownership of the table's rowtype, if it has one
5536                  */
5537                 if (tuple_class->relkind != RELKIND_INDEX)
5538                         AlterTypeOwnerInternal(tuple_class->reltype, newOwnerId);
5539
5540                 /*
5541                  * If we are operating on a table, also change the ownership of any
5542                  * indexes and sequences that belong to the table, as well as the
5543                  * table's toast table (if it has one)
5544                  */
5545                 if (tuple_class->relkind == RELKIND_RELATION ||
5546                         tuple_class->relkind == RELKIND_TOASTVALUE)
5547                 {
5548                         List       *index_oid_list;
5549                         ListCell   *i;
5550
5551                         /* Find all the indexes belonging to this relation */
5552                         index_oid_list = RelationGetIndexList(target_rel);
5553
5554                         /* For each index, recursively change its ownership */
5555                         foreach(i, index_oid_list)
5556                                 ATExecChangeOwner(lfirst_oid(i), newOwnerId, true);
5557
5558                         list_free(index_oid_list);
5559                 }
5560
5561                 if (tuple_class->relkind == RELKIND_RELATION)
5562                 {
5563                         /* If it has a toast table, recurse to change its ownership */
5564                         if (tuple_class->reltoastrelid != InvalidOid)
5565                                 ATExecChangeOwner(tuple_class->reltoastrelid, newOwnerId,
5566                                                                   true);
5567
5568                         /* If it has dependent sequences, recurse to change them too */
5569                         change_owner_recurse_to_sequences(relationOid, newOwnerId);
5570                 }
5571         }
5572
5573         ReleaseSysCache(tuple);
5574         heap_close(class_rel, RowExclusiveLock);
5575         relation_close(target_rel, NoLock);
5576 }
5577
5578 /*
5579  * change_owner_recurse_to_sequences
5580  *
5581  * Helper function for ATExecChangeOwner.  Examines pg_depend searching
5582  * for sequences that are dependent on serial columns, and changes their
5583  * ownership.
5584  */
5585 static void
5586 change_owner_recurse_to_sequences(Oid relationOid, Oid newOwnerId)
5587 {
5588         Relation        depRel;
5589         SysScanDesc scan;
5590         ScanKeyData key[2];
5591         HeapTuple       tup;
5592
5593         /*
5594          * SERIAL sequences are those having an internal dependency on one of the
5595          * table's columns (we don't care *which* column, exactly).
5596          */
5597         depRel = heap_open(DependRelationId, AccessShareLock);
5598
5599         ScanKeyInit(&key[0],
5600                                 Anum_pg_depend_refclassid,
5601                                 BTEqualStrategyNumber, F_OIDEQ,
5602                                 ObjectIdGetDatum(RelationRelationId));
5603         ScanKeyInit(&key[1],
5604                                 Anum_pg_depend_refobjid,
5605                                 BTEqualStrategyNumber, F_OIDEQ,
5606                                 ObjectIdGetDatum(relationOid));
5607         /* we leave refobjsubid unspecified */
5608
5609         scan = systable_beginscan(depRel, DependReferenceIndexId, true,
5610                                                           SnapshotNow, 2, key);
5611
5612         while (HeapTupleIsValid(tup = systable_getnext(scan)))
5613         {
5614                 Form_pg_depend depForm = (Form_pg_depend) GETSTRUCT(tup);
5615                 Relation        seqRel;
5616
5617                 /* skip dependencies other than internal dependencies on columns */
5618                 if (depForm->refobjsubid == 0 ||
5619                         depForm->classid != RelationRelationId ||
5620                         depForm->objsubid != 0 ||
5621                         depForm->deptype != DEPENDENCY_INTERNAL)
5622                         continue;
5623
5624                 /* Use relation_open just in case it's an index */
5625                 seqRel = relation_open(depForm->objid, AccessExclusiveLock);
5626
5627                 /* skip non-sequence relations */
5628                 if (RelationGetForm(seqRel)->relkind != RELKIND_SEQUENCE)
5629                 {
5630                         /* No need to keep the lock */
5631                         relation_close(seqRel, AccessExclusiveLock);
5632                         continue;
5633                 }
5634
5635                 /* We don't need to close the sequence while we alter it. */
5636                 ATExecChangeOwner(depForm->objid, newOwnerId, false);
5637
5638                 /* Now we can close it.  Keep the lock till end of transaction. */
5639                 relation_close(seqRel, NoLock);
5640         }
5641
5642         systable_endscan(scan);
5643
5644         relation_close(depRel, AccessShareLock);
5645 }
5646
5647 /*
5648  * ALTER TABLE CLUSTER ON
5649  *
5650  * The only thing we have to do is to change the indisclustered bits.
5651  */
5652 static void
5653 ATExecClusterOn(Relation rel, const char *indexName)
5654 {
5655         Oid                     indexOid;
5656
5657         indexOid = get_relname_relid(indexName, rel->rd_rel->relnamespace);
5658
5659         if (!OidIsValid(indexOid))
5660                 ereport(ERROR,
5661                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
5662                                  errmsg("index \"%s\" for table \"%s\" does not exist",
5663                                                 indexName, RelationGetRelationName(rel))));
5664
5665         /* Check index is valid to cluster on */
5666         check_index_is_clusterable(rel, indexOid, false);
5667
5668         /* And do the work */
5669         mark_index_clustered(rel, indexOid);
5670 }
5671
5672 /*
5673  * ALTER TABLE SET WITHOUT CLUSTER
5674  *
5675  * We have to find any indexes on the table that have indisclustered bit
5676  * set and turn it off.
5677  */
5678 static void
5679 ATExecDropCluster(Relation rel)
5680 {
5681         mark_index_clustered(rel, InvalidOid);
5682 }
5683
5684 /*
5685  * ALTER TABLE SET TABLESPACE
5686  */
5687 static void
5688 ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel, char *tablespacename)
5689 {
5690         Oid                     tablespaceId;
5691         AclResult       aclresult;
5692
5693         /*
5694          * We do our own permission checking because we want to allow this on
5695          * indexes.
5696          */
5697         if (rel->rd_rel->relkind != RELKIND_RELATION &&
5698                 rel->rd_rel->relkind != RELKIND_INDEX)
5699                 ereport(ERROR,
5700                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
5701                                  errmsg("\"%s\" is not a table or index",
5702                                                 RelationGetRelationName(rel))));
5703
5704         /* Permissions checks */
5705         if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
5706                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
5707                                            RelationGetRelationName(rel));
5708
5709         if (!allowSystemTableMods && IsSystemRelation(rel))
5710                 ereport(ERROR,
5711                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
5712                                  errmsg("permission denied: \"%s\" is a system catalog",
5713                                                 RelationGetRelationName(rel))));
5714
5715         /* Check that the tablespace exists */
5716         tablespaceId = get_tablespace_oid(tablespacename);
5717         if (!OidIsValid(tablespaceId))
5718                 ereport(ERROR,
5719                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
5720                                  errmsg("tablespace \"%s\" does not exist", tablespacename)));
5721
5722         /* Check its permissions */
5723         aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(), ACL_CREATE);
5724         if (aclresult != ACLCHECK_OK)
5725                 aclcheck_error(aclresult, ACL_KIND_TABLESPACE, tablespacename);
5726
5727         /* Save info for Phase 3 to do the real work */
5728         if (OidIsValid(tab->newTableSpace))
5729                 ereport(ERROR,
5730                                 (errcode(ERRCODE_SYNTAX_ERROR),
5731                                  errmsg("cannot have multiple SET TABLESPACE subcommands")));
5732         tab->newTableSpace = tablespaceId;
5733 }
5734
5735 /*
5736  * Execute ALTER TABLE SET TABLESPACE for cases where there is no tuple
5737  * rewriting to be done, so we just want to copy the data as fast as possible.
5738  */
5739 static void
5740 ATExecSetTableSpace(Oid tableOid, Oid newTableSpace)
5741 {
5742         Relation        rel;
5743         Oid                     oldTableSpace;
5744         Oid                     reltoastrelid;
5745         Oid                     reltoastidxid;
5746         RelFileNode newrnode;
5747         SMgrRelation dstrel;
5748         Relation        pg_class;
5749         HeapTuple       tuple;
5750         Form_pg_class rd_rel;
5751
5752         rel = relation_open(tableOid, NoLock);
5753
5754         /*
5755          * We can never allow moving of shared or nailed-in-cache relations,
5756          * because we can't support changing their reltablespace values.
5757          */
5758         if (rel->rd_rel->relisshared || rel->rd_isnailed)
5759                 ereport(ERROR,
5760                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
5761                                  errmsg("cannot move system relation \"%s\"",
5762                                                 RelationGetRelationName(rel))));
5763
5764         /*
5765          * Don't allow moving temp tables of other backends ... their local buffer
5766          * manager is not going to cope.
5767          */
5768         if (isOtherTempNamespace(RelationGetNamespace(rel)))
5769                 ereport(ERROR,
5770                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
5771                                  errmsg("cannot move temporary tables of other sessions")));
5772
5773         /*
5774          * No work if no change in tablespace.
5775          */
5776         oldTableSpace = rel->rd_rel->reltablespace;
5777         if (newTableSpace == oldTableSpace ||
5778                 (newTableSpace == MyDatabaseTableSpace && oldTableSpace == 0))
5779         {
5780                 relation_close(rel, NoLock);
5781                 return;
5782         }
5783
5784         reltoastrelid = rel->rd_rel->reltoastrelid;
5785         reltoastidxid = rel->rd_rel->reltoastidxid;
5786
5787         /* Get a modifiable copy of the relation's pg_class row */
5788         pg_class = heap_open(RelationRelationId, RowExclusiveLock);
5789
5790         tuple = SearchSysCacheCopy(RELOID,
5791                                                            ObjectIdGetDatum(tableOid),
5792                                                            0, 0, 0);
5793         if (!HeapTupleIsValid(tuple))
5794                 elog(ERROR, "cache lookup failed for relation %u", tableOid);
5795         rd_rel = (Form_pg_class) GETSTRUCT(tuple);
5796
5797         /* create another storage file. Is it a little ugly ? */
5798         /* NOTE: any conflict in relfilenode value will be caught here */
5799         newrnode = rel->rd_node;
5800         newrnode.spcNode = newTableSpace;
5801
5802         dstrel = smgropen(newrnode);
5803         smgrcreate(dstrel, rel->rd_istemp, false);
5804
5805         /* copy relation data to the new physical file */
5806         copy_relation_data(rel, dstrel);
5807
5808         /* schedule unlinking old physical file */
5809         RelationOpenSmgr(rel);
5810         smgrscheduleunlink(rel->rd_smgr, rel->rd_istemp);
5811
5812         /*
5813          * Now drop smgr references.  The source was already dropped by
5814          * smgrscheduleunlink.
5815          */
5816         smgrclose(dstrel);
5817
5818         /* update the pg_class row */
5819         rd_rel->reltablespace = (newTableSpace == MyDatabaseTableSpace) ? InvalidOid : newTableSpace;
5820         simple_heap_update(pg_class, &tuple->t_self, tuple);
5821         CatalogUpdateIndexes(pg_class, tuple);
5822
5823         heap_freetuple(tuple);
5824
5825         heap_close(pg_class, RowExclusiveLock);
5826
5827         relation_close(rel, NoLock);
5828
5829         /* Make sure the reltablespace change is visible */
5830         CommandCounterIncrement();
5831
5832         /* Move associated toast relation and/or index, too */
5833         if (OidIsValid(reltoastrelid))
5834                 ATExecSetTableSpace(reltoastrelid, newTableSpace);
5835         if (OidIsValid(reltoastidxid))
5836                 ATExecSetTableSpace(reltoastidxid, newTableSpace);
5837 }
5838
5839 /*
5840  * Copy data, block by block
5841  */
5842 static void
5843 copy_relation_data(Relation rel, SMgrRelation dst)
5844 {
5845         SMgrRelation src;
5846         bool            use_wal;
5847         BlockNumber nblocks;
5848         BlockNumber blkno;
5849         char            buf[BLCKSZ];
5850         Page            page = (Page) buf;
5851
5852         /*
5853          * Since we copy the file directly without looking at the shared buffers,
5854          * we'd better first flush out any pages of the source relation that are
5855          * in shared buffers.  We assume no new changes will be made while we are
5856          * holding exclusive lock on the rel.
5857          */
5858         FlushRelationBuffers(rel);
5859
5860         /*
5861          * We need to log the copied data in WAL iff WAL archiving is enabled AND
5862          * it's not a temp rel.
5863          */
5864         use_wal = XLogArchivingActive() && !rel->rd_istemp;
5865
5866         nblocks = RelationGetNumberOfBlocks(rel);
5867         /* RelationGetNumberOfBlocks will certainly have opened rd_smgr */
5868         src = rel->rd_smgr;
5869
5870         for (blkno = 0; blkno < nblocks; blkno++)
5871         {
5872                 smgrread(src, blkno, buf);
5873
5874                 /* XLOG stuff */
5875                 if (use_wal)
5876                 {
5877                         xl_heap_newpage xlrec;
5878                         XLogRecPtr      recptr;
5879                         XLogRecData rdata[2];
5880
5881                         /* NO ELOG(ERROR) from here till newpage op is logged */
5882                         START_CRIT_SECTION();
5883
5884                         xlrec.node = dst->smgr_rnode;
5885                         xlrec.blkno = blkno;
5886
5887                         rdata[0].data = (char *) &xlrec;
5888                         rdata[0].len = SizeOfHeapNewpage;
5889                         rdata[0].buffer = InvalidBuffer;
5890                         rdata[0].next = &(rdata[1]);
5891
5892                         rdata[1].data = (char *) page;
5893                         rdata[1].len = BLCKSZ;
5894                         rdata[1].buffer = InvalidBuffer;
5895                         rdata[1].next = NULL;
5896
5897                         recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_NEWPAGE, rdata);
5898
5899                         PageSetLSN(page, recptr);
5900                         PageSetTLI(page, ThisTimeLineID);
5901
5902                         END_CRIT_SECTION();
5903                 }
5904
5905                 /*
5906                  * Now write the page.  We say isTemp = true even if it's not a temp
5907                  * rel, because there's no need for smgr to schedule an fsync for this
5908                  * write; we'll do it ourselves below.
5909                  */
5910                 smgrwrite(dst, blkno, buf, true);
5911         }
5912
5913         /*
5914          * If the rel isn't temp, we must fsync it down to disk before it's safe
5915          * to commit the transaction.  (For a temp rel we don't care since the rel
5916          * will be uninteresting after a crash anyway.)
5917          *
5918          * It's obvious that we must do this when not WAL-logging the copy. It's
5919          * less obvious that we have to do it even if we did WAL-log the copied
5920          * pages. The reason is that since we're copying outside shared buffers, a
5921          * CHECKPOINT occurring during the copy has no way to flush the previously
5922          * written data to disk (indeed it won't know the new rel even exists).  A
5923          * crash later on would replay WAL from the checkpoint, therefore it
5924          * wouldn't replay our earlier WAL entries. If we do not fsync those pages
5925          * here, they might still not be on disk when the crash occurs.
5926          */
5927         if (!rel->rd_istemp)
5928                 smgrimmedsync(dst);
5929 }
5930
5931 /*
5932  * ALTER TABLE ENABLE/DISABLE TRIGGER
5933  *
5934  * We just pass this off to trigger.c.
5935  */
5936 static void
5937 ATExecEnableDisableTrigger(Relation rel, char *trigname,
5938                                                    bool enable, bool skip_system)
5939 {
5940         EnableDisableTrigger(rel, trigname, enable, skip_system);
5941 }
5942
5943 static char *
5944 decompile_conbin(HeapTuple contuple, TupleDesc tupledesc)
5945 {
5946         Form_pg_constraint con = (Form_pg_constraint)(GETSTRUCT(contuple));
5947         bool isnull;
5948         Datum d;
5949
5950         d = fastgetattr(contuple, Anum_pg_constraint_conbin, tupledesc, &isnull);
5951         if (isnull)
5952                 elog(ERROR, "conbin is null for constraint \"%s\"", NameStr(con->conname));
5953         d = DirectFunctionCall2(pg_get_expr, d, ObjectIdGetDatum(con->conrelid));
5954         return DatumGetCString(DirectFunctionCall1(textout,d));
5955 }
5956
5957
5958 /* ALTER TABLE INHERIT */
5959
5960 /* Add a parent to the child's parents. This verifies that all the columns and
5961  * check constraints of the parent appear in the child and that they have the
5962  * same data type and expressions.
5963  */
5964
5965 static void
5966 ATExecAddInherits(Relation rel, RangeVar *parent)
5967 {
5968         Relation        relation,
5969                                 catalogRelation;
5970         SysScanDesc scan;
5971         ScanKeyData key;
5972         HeapTuple       inheritsTuple;
5973         int4            inhseqno;
5974         List       *children;
5975
5976
5977         /* XXX is this enough locking? */
5978         relation = heap_openrv(parent, AccessShareLock);
5979
5980         /*
5981          * Must be owner of both parent and child -- child is taken care of by
5982          * ATSimplePermissions call in ATPrepCmd
5983          */
5984         ATSimplePermissions(relation, false);
5985
5986         /* Permanent rels cannot inherit from temporary ones */
5987         if (!isTempNamespace(RelationGetNamespace(rel)) &&
5988                 isTempNamespace(RelationGetNamespace(relation)))
5989                 ereport(ERROR,
5990                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
5991                                  errmsg("cannot inherit from temporary relation \"%s\"",
5992                                                 parent->relname)));
5993
5994         /* If parent has OIDs then all children must have OIDs */
5995         if (relation->rd_rel->relhasoids && !rel->rd_rel->relhasoids)
5996                 ereport(ERROR,
5997                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
5998                                  errmsg("table \"%s\" without OIDs cannot inherit from table \"%s\" with OIDs",
5999                                                 RelationGetRelationName(rel), parent->relname)));
6000
6001         /*
6002          * Reject duplications in the list of parents. We scan through the list of
6003          * parents in pg_inherit and keep track of the first open inhseqno slot
6004          * found to use for the new parent.
6005          */
6006         catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock);
6007         ScanKeyInit(&key,
6008                                 Anum_pg_inherits_inhrelid,
6009                                 BTEqualStrategyNumber, F_OIDEQ,
6010                                 ObjectIdGetDatum(RelationGetRelid(rel)));
6011         scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId,
6012                                 true, SnapshotNow, 1, &key);
6013         inhseqno = 0;                           /* inhseqno sequences are supposed to start at
6014                                                                  * 1 */
6015         while (HeapTupleIsValid(inheritsTuple = systable_getnext(scan)))
6016         {
6017                 Form_pg_inherits inh = (Form_pg_inherits) GETSTRUCT(inheritsTuple);
6018
6019                 if (inh->inhparent == RelationGetRelid(relation))
6020                         ereport(ERROR,
6021                                         (errcode(ERRCODE_DUPLICATE_TABLE),
6022                                          errmsg("inherited relation \"%s\" duplicated",
6023                                                         parent->relname)));
6024                 if (inh->inhseqno == inhseqno + 1)
6025                         inhseqno = inh->inhseqno;
6026         }
6027         systable_endscan(scan);
6028         heap_close(catalogRelation, RowExclusiveLock);
6029
6030         /*
6031          * If the new parent is found in our list of inheritors we have a circular
6032          * structure
6033          */
6034
6035         /* this routine is actually in the planner */
6036         children = find_all_inheritors(RelationGetRelid(rel));
6037
6038         if (list_member_oid(children, RelationGetRelid(relation)))
6039                 ereport(ERROR,
6040                                 (errcode(ERRCODE_DUPLICATE_TABLE),
6041                                  errmsg("circular inheritance structure found, \"%s\" is already a child of \"%s\"",
6042                                                 parent->relname, RelationGetRelationName(rel))));
6043
6044
6045         /* Match up the columns and bump attinhcount and attislocal */
6046         MergeAttributesIntoExisting(rel, relation);
6047
6048         /* Match up the constraints and make sure they're present in child */
6049         MergeConstraintsIntoExisting(rel, relation);
6050
6051         /*
6052          * Use this refactored part of StoreCatalogInheritance which CREATE TABLE
6053          * uses to add the pg_inherit line
6054          */
6055         catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock);
6056         StoreCatalogInheritance1(RelationGetRelid(rel), RelationGetRelid(relation),
6057                         inhseqno + 1, catalogRelation);
6058         heap_close(catalogRelation, RowExclusiveLock);
6059
6060         heap_close(relation, AccessShareLock);
6061 }
6062
6063 /*
6064  * Check columns in child table match up with columns in parent
6065  *
6066  * Called by ATExecAddInherits
6067  *
6068  * Currently all columns must be found in child. Missing columns are an error.
6069  * One day we might consider creating new columns like CREATE TABLE does.
6070  *
6071  * The data type must match perfectly, if the parent column is NOT NULL then
6072  * the child table must be as well. Defaults are ignored however.
6073  *
6074  */
6075
6076 static void
6077 MergeAttributesIntoExisting(Relation rel, Relation relation)
6078 {
6079         Relation        attrdesc;
6080         AttrNumber      parent_attno,
6081                                 child_attno;
6082         TupleDesc       tupleDesc;
6083         TupleConstr *constr;
6084         HeapTuple       tuple;
6085
6086         child_attno = RelationGetNumberOfAttributes(rel);
6087
6088         tupleDesc = RelationGetDescr(relation);
6089         constr = tupleDesc->constr;
6090
6091         for (parent_attno = 1; parent_attno <= tupleDesc->natts;
6092                  parent_attno++)
6093         {
6094                 Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1];
6095                 char       *attributeName = NameStr(attribute->attname);
6096
6097                 /* Ignore dropped columns in the parent. */
6098                 if (attribute->attisdropped)
6099                         continue;
6100
6101                 /* Does it conflict with an existing column? */
6102                 attrdesc = heap_open(AttributeRelationId, RowExclusiveLock);
6103
6104                 tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), attributeName);
6105                 if (HeapTupleIsValid(tuple))
6106                 {
6107                         /*
6108                          * Yes, try to merge the two column definitions. They must have
6109                          * the same type and typmod.
6110                          */
6111                         Form_pg_attribute childatt = (Form_pg_attribute) GETSTRUCT(tuple);
6112
6113                         if (attribute->atttypid != childatt->atttypid ||
6114                                 attribute->atttypmod != childatt->atttypmod ||
6115                                 (attribute->attnotnull && !childatt->attnotnull))
6116                                 ereport(ERROR,
6117                                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
6118                                                  errmsg("child table \"%s\" has different type for column \"%s\"",
6119                                 RelationGetRelationName(rel), NameStr(attribute->attname))));
6120
6121                         childatt->attinhcount++;
6122                         simple_heap_update(attrdesc, &tuple->t_self, tuple);
6123                         /* XXX strength reduce open indexes to outside loop? */
6124                         CatalogUpdateIndexes(attrdesc, tuple);
6125                         heap_freetuple(tuple);
6126
6127                         /*
6128                          * We don't touch default at all since we're not making any other
6129                          * DDL changes to the child
6130                          */
6131                 }
6132                 else
6133                 {
6134                         /*
6135                          * No, create a new inherited column
6136                          *
6137                          * Creating inherited columns in this case seems to be unpopular.
6138                          * In the common use case of partitioned tables it's a foot-gun.
6139                          */
6140                         ereport(ERROR,
6141                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
6142                                          errmsg("child table missing column \"%s\"",
6143                                                         NameStr(attribute->attname))));
6144                 }
6145                 heap_close(attrdesc, RowExclusiveLock);
6146         }
6147
6148 }
6149
6150 /*
6151  * Check constraints in child table match up with constraints in parent
6152  *
6153  * Called by ATExecAddInherits
6154  *
6155  * Currently all constraints in parent must be present in the child. One day we
6156  * may consider adding new constraints like CREATE TABLE does. We may also want
6157  * to allow an optional flag on parent table constraints indicating they are
6158  * intended to ONLY apply to the master table, not to the children. That would
6159  * make it possible to ensure no records are mistakenly inserted into the
6160  * master in partitioned tables rather than the appropriate child.
6161  *
6162  * XXX this is O(n^2) which may be issue with tables with hundreds of
6163  * constraints. As long as tables have more like 10 constraints it shouldn't be
6164  * an issue though. Even 100 constraints ought not be the end of the world.
6165  */
6166
6167 static void
6168 MergeConstraintsIntoExisting(Relation rel, Relation relation)
6169 {
6170         Relation        catalogRelation;
6171         TupleDesc       tupleDesc;
6172         SysScanDesc scan;
6173         ScanKeyData key;
6174         HeapTuple       constraintTuple;
6175         ListCell   *elem;
6176         List       *constraints;
6177
6178         /* First gather up the child's constraint definitions */
6179         catalogRelation = heap_open(ConstraintRelationId, AccessShareLock);
6180         tupleDesc = RelationGetDescr(catalogRelation);
6181
6182         ScanKeyInit(&key,
6183                                 Anum_pg_constraint_conrelid,
6184                                 BTEqualStrategyNumber,
6185                                 F_OIDEQ,
6186                                 ObjectIdGetDatum(RelationGetRelid(rel)));
6187         scan = systable_beginscan(catalogRelation, ConstraintRelidIndexId,
6188                                 true, SnapshotNow, 1, &key);
6189         constraints = NIL;
6190
6191         while (HeapTupleIsValid(constraintTuple = systable_getnext(scan)))
6192         {
6193                 Form_pg_constraint con = (Form_pg_constraint) (GETSTRUCT(constraintTuple));
6194
6195                 if (con->contype != CONSTRAINT_CHECK)
6196                         continue;
6197                 /* XXX Do I need the copytuple here? */
6198                 constraints = lappend(constraints, heap_copytuple(constraintTuple));
6199         }
6200         systable_endscan(scan);
6201
6202         /* Then loop through the parent's constraints looking for them in the list */
6203         ScanKeyInit(&key,
6204                                 Anum_pg_constraint_conrelid,
6205                                 BTEqualStrategyNumber,
6206                                 F_OIDEQ,
6207                                 ObjectIdGetDatum(RelationGetRelid(relation)));
6208         scan = systable_beginscan(catalogRelation, ConstraintRelidIndexId, true,
6209                                 SnapshotNow, 1, &key);
6210         while (HeapTupleIsValid(constraintTuple = systable_getnext(scan)))
6211         {
6212                 bool            found = false;
6213                 Form_pg_constraint parent_con = (Form_pg_constraint) (GETSTRUCT(constraintTuple));
6214                 Form_pg_constraint child_con = NULL;
6215                 HeapTuple       child_contuple = NULL;
6216
6217                 if (parent_con->contype != CONSTRAINT_CHECK)
6218                         continue;
6219
6220                 foreach(elem, constraints)
6221                 {
6222                         child_contuple = lfirst(elem);
6223                         child_con = (Form_pg_constraint) (GETSTRUCT(child_contuple));
6224                         if (!strcmp(NameStr(parent_con->conname),
6225                                                 NameStr(child_con->conname)))
6226                         {
6227                                 found = true;
6228                                 break;
6229                         }
6230                 }
6231
6232                 if (!found)
6233                         ereport(ERROR,
6234                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
6235                                          errmsg("child table missing constraint matching parent table constraint \"%s\"",
6236                                                         NameStr(parent_con->conname))));
6237
6238                 if (parent_con->condeferrable != child_con->condeferrable ||
6239                         parent_con->condeferred != child_con->condeferred ||
6240                         parent_con->contypid != child_con->contypid ||
6241                         strcmp(decompile_conbin(constraintTuple, tupleDesc),
6242                                    decompile_conbin(child_contuple, tupleDesc)))
6243                         ereport(ERROR,
6244                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
6245                                          errmsg("constraint definition for CHECK constraint \"%s\" doesn't match",
6246                                                         NameStr(parent_con->conname))));
6247
6248                 /*
6249                  * TODO: add conislocal,coninhcount to constraints. This is where we
6250                  * would have to bump them just like attributes
6251                  */
6252         }
6253         systable_endscan(scan);
6254         heap_close(catalogRelation, AccessShareLock);
6255 }
6256
6257 /* ALTER TABLE NO INHERIT */
6258
6259 /* Drop a parent from the child's parents. This just adjusts the attinhcount
6260  * and attislocal of the columns and removes the pg_inherit and pg_depend
6261  * entries.
6262  *
6263  * If attinhcount goes to 0 then attislocal gets set to true. If it goes back up
6264  * attislocal stays 0 which means if a child is ever removed from a parent then
6265  * its columns will never be automatically dropped which may surprise. But at
6266  * least we'll never surprise by dropping columns someone isn't expecting to be
6267  * dropped which would actually mean data loss.
6268  */
6269
6270 static void
6271 ATExecDropInherits(Relation rel, RangeVar *parent)
6272 {
6273
6274
6275         Relation        catalogRelation;
6276         SysScanDesc scan;
6277         ScanKeyData key[2];
6278         HeapTuple       inheritsTuple,
6279                                 attributeTuple,
6280                                 depTuple;
6281         Oid                     inhparent;
6282         Oid                     dropparent;
6283         int                     found = false;
6284
6285         /*
6286          * Get the OID of parent -- if no schema is specified use the regular
6287          * search path and only drop the one table that's found. We could try to
6288          * be clever and look at each parent and see if it matches but that would
6289          * be inconsistent with other operations I think.
6290          */
6291
6292         Assert(rel);
6293         Assert(parent);
6294
6295         dropparent = RangeVarGetRelid(parent, false);
6296
6297         /* Search through the direct parents of rel looking for dropparent oid */
6298
6299         catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock);
6300         ScanKeyInit(key,
6301                                 Anum_pg_inherits_inhrelid,
6302                                 BTEqualStrategyNumber, F_OIDEQ,
6303                                 ObjectIdGetDatum(RelationGetRelid(rel)));
6304         scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId, true, SnapshotNow, 1, key);
6305         while (!found && HeapTupleIsValid(inheritsTuple = systable_getnext(scan)))
6306         {
6307                 inhparent = ((Form_pg_inherits) GETSTRUCT(inheritsTuple))->inhparent;
6308                 if (inhparent == dropparent)
6309                 {
6310                         simple_heap_delete(catalogRelation, &inheritsTuple->t_self);
6311                         found = true;
6312                 }
6313         }
6314         systable_endscan(scan);
6315         heap_close(catalogRelation, RowExclusiveLock);
6316
6317
6318         if (!found)
6319         {
6320                 if (parent->schemaname)
6321                         ereport(ERROR,
6322                                         (errcode(ERRCODE_UNDEFINED_TABLE),
6323                           errmsg("relation \"%s.%s\" is not a parent of relation \"%s\"",
6324                                          parent->schemaname, parent->relname, RelationGetRelationName(rel))));
6325                 else
6326                         ereport(ERROR,
6327                                         (errcode(ERRCODE_UNDEFINED_TABLE),
6328                                  errmsg("relation \"%s\" is not a parent of relation \"%s\"",
6329                                                 parent->relname, RelationGetRelationName(rel))));
6330         }
6331
6332         /* Search through columns looking for matching columns from parent table */
6333
6334         catalogRelation = heap_open(AttributeRelationId, RowExclusiveLock);
6335         ScanKeyInit(key,
6336                                 Anum_pg_attribute_attrelid,
6337                                 BTEqualStrategyNumber,
6338                                 F_OIDEQ,
6339                                 ObjectIdGetDatum(RelationGetRelid(rel)));
6340         scan = systable_beginscan(catalogRelation, AttributeRelidNumIndexId,
6341                                 true, SnapshotNow, 1, key);
6342         while (HeapTupleIsValid(attributeTuple = systable_getnext(scan)))
6343         {
6344                 Form_pg_attribute att = ((Form_pg_attribute) GETSTRUCT(attributeTuple));
6345
6346                 /*
6347                  * Not an inherited column at all (do NOT use islocal for this
6348                  * test--it can be true for inherited columns)
6349                  */
6350                 if (att->attinhcount == 0)
6351                         continue;
6352                 if (att->attisdropped)
6353                         continue;
6354
6355                 if (SearchSysCacheExistsAttName(dropparent, NameStr(att->attname)))
6356                 {
6357                         /* Decrement inhcount and possibly set islocal to 1 */
6358                         HeapTuple       copyTuple = heap_copytuple(attributeTuple);
6359                         Form_pg_attribute copy_att = ((Form_pg_attribute) GETSTRUCT(copyTuple));
6360
6361                         copy_att->attinhcount--;
6362                         if (copy_att->attinhcount == 0)
6363                                 copy_att->attislocal = true;
6364
6365                         simple_heap_update(catalogRelation, &copyTuple->t_self, copyTuple);
6366
6367                         /*
6368                          * XXX "Avoid using it for multiple tuples, since opening the
6369                          * indexes and building the index info structures is moderately
6370                          * expensive." Perhaps this can be moved outside the loop or else
6371                          * at least the CatalogOpenIndexes/CatalogCloseIndexes moved
6372                          * outside the loop but when I try that it seg faults?!
6373                          */
6374                         CatalogUpdateIndexes(catalogRelation, copyTuple);
6375                         heap_freetuple(copyTuple);
6376                 }
6377         }
6378         systable_endscan(scan);
6379         heap_close(catalogRelation, RowExclusiveLock);
6380
6381
6382         /*
6383          * Drop the dependency
6384          *
6385          * There's no convenient way to do this, so go trawling through pg_depend
6386          */
6387
6388         catalogRelation = heap_open(DependRelationId, RowExclusiveLock);
6389
6390         ScanKeyInit(&key[0],
6391                                 Anum_pg_depend_classid,
6392                                 BTEqualStrategyNumber, F_OIDEQ,
6393                                 RelationRelationId);
6394         ScanKeyInit(&key[1],
6395                                 Anum_pg_depend_objid,
6396                                 BTEqualStrategyNumber, F_OIDEQ,
6397                                 ObjectIdGetDatum(RelationGetRelid(rel)));
6398
6399         scan = systable_beginscan(catalogRelation, DependDependerIndexId, true,
6400                                                           SnapshotNow, 2, key);
6401
6402         while (HeapTupleIsValid(depTuple = systable_getnext(scan)))
6403         {
6404                 Form_pg_depend dep = (Form_pg_depend) GETSTRUCT(depTuple);
6405
6406                 if (dep->refclassid == RelationRelationId &&
6407                         dep->refobjid == dropparent &&
6408                         dep->deptype == DEPENDENCY_NORMAL)
6409                 {
6410                         /*
6411                          * Only delete a single dependency -- there shouldn't be more but
6412                          * just in case...
6413                          */
6414                         simple_heap_delete(catalogRelation, &depTuple->t_self);
6415
6416                         break;
6417                 }
6418         }
6419         systable_endscan(scan);
6420
6421         heap_close(catalogRelation, RowExclusiveLock);
6422 }
6423
6424
6425 /*
6426  * ALTER TABLE CREATE TOAST TABLE
6427  *
6428  * Note: this is also invoked from outside this module; in such cases we
6429  * expect the caller to have verified that the relation is a table and we
6430  * have all the right permissions.      Callers expect this function
6431  * to end with CommandCounterIncrement if it makes any changes.
6432  */
6433 void
6434 AlterTableCreateToastTable(Oid relOid, bool silent)
6435 {
6436         Relation        rel;
6437         HeapTuple       reltup;
6438         TupleDesc       tupdesc;
6439         bool            shared_relation;
6440         Relation        class_rel;
6441         Oid                     toast_relid;
6442         Oid                     toast_idxid;
6443         char            toast_relname[NAMEDATALEN];
6444         char            toast_idxname[NAMEDATALEN];
6445         IndexInfo  *indexInfo;
6446         Oid                     classObjectId[2];
6447         ObjectAddress baseobject,
6448                                 toastobject;
6449
6450         /*
6451          * Grab an exclusive lock on the target table, which we will NOT release
6452          * until end of transaction.  (This is probably redundant in all present
6453          * uses...)
6454          */
6455         rel = heap_open(relOid, AccessExclusiveLock);
6456
6457         /*
6458          * Toast table is shared if and only if its parent is.
6459          *
6460          * We cannot allow toasting a shared relation after initdb (because
6461          * there's no way to mark it toasted in other databases' pg_class).
6462          * Unfortunately we can't distinguish initdb from a manually started
6463          * standalone backend (toasting happens after the bootstrap phase, so
6464          * checking IsBootstrapProcessingMode() won't work).  However, we can at
6465          * least prevent this mistake under normal multi-user operation.
6466          */
6467         shared_relation = rel->rd_rel->relisshared;
6468         if (shared_relation && IsUnderPostmaster)
6469                 ereport(ERROR,
6470                                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
6471                                  errmsg("shared tables cannot be toasted after initdb")));
6472
6473         /*
6474          * Is it already toasted?
6475          */
6476         if (rel->rd_rel->reltoastrelid != InvalidOid)
6477         {
6478                 if (silent)
6479                 {
6480                         heap_close(rel, NoLock);
6481                         return;
6482                 }
6483
6484                 ereport(ERROR,
6485                                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
6486                                  errmsg("table \"%s\" already has a TOAST table",
6487                                                 RelationGetRelationName(rel))));
6488         }
6489
6490         /*
6491          * Check to see whether the table actually needs a TOAST table.
6492          */
6493         if (!needs_toast_table(rel))
6494         {
6495                 if (silent)
6496                 {
6497                         heap_close(rel, NoLock);
6498                         return;
6499                 }
6500
6501                 ereport(ERROR,
6502                                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
6503                                  errmsg("table \"%s\" does not need a TOAST table",
6504                                                 RelationGetRelationName(rel))));
6505         }
6506
6507         /*
6508          * Create the toast table and its index
6509          */
6510         snprintf(toast_relname, sizeof(toast_relname),
6511                          "pg_toast_%u", relOid);
6512         snprintf(toast_idxname, sizeof(toast_idxname),
6513                          "pg_toast_%u_index", relOid);
6514
6515         /* this is pretty painful...  need a tuple descriptor */
6516         tupdesc = CreateTemplateTupleDesc(3, false);
6517         TupleDescInitEntry(tupdesc, (AttrNumber) 1,
6518                                            "chunk_id",
6519                                            OIDOID,
6520                                            -1, 0);
6521         TupleDescInitEntry(tupdesc, (AttrNumber) 2,
6522                                            "chunk_seq",
6523                                            INT4OID,
6524                                            -1, 0);
6525         TupleDescInitEntry(tupdesc, (AttrNumber) 3,
6526                                            "chunk_data",
6527                                            BYTEAOID,
6528                                            -1, 0);
6529
6530         /*
6531          * Ensure that the toast table doesn't itself get toasted, or we'll be
6532          * toast :-(.  This is essential for chunk_data because type bytea is
6533          * toastable; hit the other two just to be sure.
6534          */
6535         tupdesc->attrs[0]->attstorage = 'p';
6536         tupdesc->attrs[1]->attstorage = 'p';
6537         tupdesc->attrs[2]->attstorage = 'p';
6538
6539         /*
6540          * Note: the toast relation is placed in the regular pg_toast namespace
6541          * even if its master relation is a temp table.  There cannot be any
6542          * naming collision, and the toast rel will be destroyed when its master
6543          * is, so there's no need to handle the toast rel as temp.
6544          */
6545         toast_relid = heap_create_with_catalog(toast_relname,
6546                                                                                    PG_TOAST_NAMESPACE,
6547                                                                                    rel->rd_rel->reltablespace,
6548                                                                                    InvalidOid,
6549                                                                                    rel->rd_rel->relowner,
6550                                                                                    tupdesc,
6551                                                                                    RELKIND_TOASTVALUE,
6552                                                                                    shared_relation,
6553                                                                                    true,
6554                                                                                    0,
6555                                                                                    ONCOMMIT_NOOP,
6556                                                                                    true);
6557
6558         /* make the toast relation visible, else index creation will fail */
6559         CommandCounterIncrement();
6560
6561         /*
6562          * Create unique index on chunk_id, chunk_seq.
6563          *
6564          * NOTE: the normal TOAST access routines could actually function with a
6565          * single-column index on chunk_id only. However, the slice access
6566          * routines use both columns for faster access to an individual chunk. In
6567          * addition, we want it to be unique as a check against the possibility of
6568          * duplicate TOAST chunk OIDs. The index might also be a little more
6569          * efficient this way, since btree isn't all that happy with large numbers
6570          * of equal keys.
6571          */
6572
6573         indexInfo = makeNode(IndexInfo);
6574         indexInfo->ii_NumIndexAttrs = 2;
6575         indexInfo->ii_KeyAttrNumbers[0] = 1;
6576         indexInfo->ii_KeyAttrNumbers[1] = 2;
6577         indexInfo->ii_Expressions = NIL;
6578         indexInfo->ii_ExpressionsState = NIL;
6579         indexInfo->ii_Predicate = NIL;
6580         indexInfo->ii_PredicateState = NIL;
6581         indexInfo->ii_Unique = true;
6582
6583         classObjectId[0] = OID_BTREE_OPS_OID;
6584         classObjectId[1] = INT4_BTREE_OPS_OID;
6585
6586         toast_idxid = index_create(toast_relid, toast_idxname, InvalidOid,
6587                                                            indexInfo,
6588                                                            BTREE_AM_OID,
6589                                                            rel->rd_rel->reltablespace,
6590                                                            classObjectId,
6591                                                            true, true, false, true, false);
6592
6593         /*
6594          * Store the toast table's OID in the parent relation's pg_class row
6595          */
6596         class_rel = heap_open(RelationRelationId, RowExclusiveLock);
6597
6598         reltup = SearchSysCacheCopy(RELOID,
6599                                                                 ObjectIdGetDatum(relOid),
6600                                                                 0, 0, 0);
6601         if (!HeapTupleIsValid(reltup))
6602                 elog(ERROR, "cache lookup failed for relation %u", relOid);
6603
6604         ((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid = toast_relid;
6605
6606         simple_heap_update(class_rel, &reltup->t_self, reltup);
6607
6608         /* Keep catalog indexes current */
6609         CatalogUpdateIndexes(class_rel, reltup);
6610
6611         heap_freetuple(reltup);
6612
6613         heap_close(class_rel, RowExclusiveLock);
6614
6615         /*
6616          * Register dependency from the toast table to the master, so that the
6617          * toast table will be deleted if the master is.
6618          */
6619         baseobject.classId = RelationRelationId;
6620         baseobject.objectId = relOid;
6621         baseobject.objectSubId = 0;
6622         toastobject.classId = RelationRelationId;
6623         toastobject.objectId = toast_relid;
6624         toastobject.objectSubId = 0;
6625
6626         recordDependencyOn(&toastobject, &baseobject, DEPENDENCY_INTERNAL);
6627
6628         /*
6629          * Clean up and make changes visible
6630          */
6631         heap_close(rel, NoLock);
6632
6633         CommandCounterIncrement();
6634 }
6635
6636 /*
6637  * Check to see whether the table needs a TOAST table.  It does only if
6638  * (1) there are any toastable attributes, and (2) the maximum length
6639  * of a tuple could exceed TOAST_TUPLE_THRESHOLD.  (We don't want to
6640  * create a toast table for something like "f1 varchar(20)".)
6641  */
6642 static bool
6643 needs_toast_table(Relation rel)
6644 {
6645         int32           data_length = 0;
6646         bool            maxlength_unknown = false;
6647         bool            has_toastable_attrs = false;
6648         TupleDesc       tupdesc;
6649         Form_pg_attribute *att;
6650         int32           tuple_length;
6651         int                     i;
6652
6653         tupdesc = rel->rd_att;
6654         att = tupdesc->attrs;
6655
6656         for (i = 0; i < tupdesc->natts; i++)
6657         {
6658                 if (att[i]->attisdropped)
6659                         continue;
6660                 data_length = att_align(data_length, att[i]->attalign);
6661                 if (att[i]->attlen > 0)
6662                 {
6663                         /* Fixed-length types are never toastable */
6664                         data_length += att[i]->attlen;
6665                 }
6666                 else
6667                 {
6668                         int32           maxlen = type_maximum_size(att[i]->atttypid,
6669                                                                                                    att[i]->atttypmod);
6670
6671                         if (maxlen < 0)
6672                                 maxlength_unknown = true;
6673                         else
6674                                 data_length += maxlen;
6675                         if (att[i]->attstorage != 'p')
6676                                 has_toastable_attrs = true;
6677                 }
6678         }
6679         if (!has_toastable_attrs)
6680                 return false;                   /* nothing to toast? */
6681         if (maxlength_unknown)
6682                 return true;                    /* any unlimited-length attrs? */
6683         tuple_length = MAXALIGN(offsetof(HeapTupleHeaderData, t_bits) +
6684                                                         BITMAPLEN(tupdesc->natts)) +
6685                 MAXALIGN(data_length);
6686         return (tuple_length > TOAST_TUPLE_THRESHOLD);
6687 }
6688
6689
6690 /*
6691  * Execute ALTER TABLE SET SCHEMA
6692  *
6693  * Note: caller must have checked ownership of the relation already
6694  */
6695 void
6696 AlterTableNamespace(RangeVar *relation, const char *newschema)
6697 {
6698         Relation        rel;
6699         Oid                     relid;
6700         Oid                     oldNspOid;
6701         Oid                     nspOid;
6702         Relation        classRel;
6703
6704         rel = heap_openrv(relation, AccessExclusiveLock);
6705
6706         /* heap_openrv allows TOAST, but we don't want to */
6707         if (rel->rd_rel->relkind == RELKIND_TOASTVALUE)
6708                 ereport(ERROR,
6709                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
6710                                  errmsg("\"%s\" is a TOAST relation",
6711                                                 RelationGetRelationName(rel))));
6712
6713         relid = RelationGetRelid(rel);
6714         oldNspOid = RelationGetNamespace(rel);
6715
6716         /* get schema OID and check its permissions */
6717         nspOid = LookupCreationNamespace(newschema);
6718
6719         if (oldNspOid == nspOid)
6720                 ereport(ERROR,
6721                                 (errcode(ERRCODE_DUPLICATE_TABLE),
6722                                  errmsg("relation \"%s\" is already in schema \"%s\"",
6723                                                 RelationGetRelationName(rel),
6724                                                 newschema)));
6725
6726         /* disallow renaming into or out of temp schemas */
6727         if (isAnyTempNamespace(nspOid) || isAnyTempNamespace(oldNspOid))
6728                 ereport(ERROR,
6729                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
6730                         errmsg("cannot move objects into or out of temporary schemas")));
6731
6732         /* same for TOAST schema */
6733         if (nspOid == PG_TOAST_NAMESPACE || oldNspOid == PG_TOAST_NAMESPACE)
6734                 ereport(ERROR,
6735                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
6736                                  errmsg("cannot move objects into or out of TOAST schema")));
6737
6738         /* OK, modify the pg_class row and pg_depend entry */
6739         classRel = heap_open(RelationRelationId, RowExclusiveLock);
6740
6741         AlterRelationNamespaceInternal(classRel, relid, oldNspOid, nspOid, true);
6742
6743         /* Fix the table's rowtype too */
6744         AlterTypeNamespaceInternal(rel->rd_rel->reltype, nspOid, false);
6745
6746         /* Fix other dependent stuff */
6747         if (rel->rd_rel->relkind == RELKIND_RELATION)
6748         {
6749                 AlterIndexNamespaces(classRel, rel, oldNspOid, nspOid);
6750                 AlterSeqNamespaces(classRel, rel, oldNspOid, nspOid, newschema);
6751                 AlterConstraintNamespaces(relid, oldNspOid, nspOid, false);
6752         }
6753
6754         heap_close(classRel, RowExclusiveLock);
6755
6756         /* close rel, but keep lock until commit */
6757         relation_close(rel, NoLock);
6758 }
6759
6760 /*
6761  * The guts of relocating a relation to another namespace: fix the pg_class
6762  * entry, and the pg_depend entry if any.  Caller must already have
6763  * opened and write-locked pg_class.
6764  */
6765 void
6766 AlterRelationNamespaceInternal(Relation classRel, Oid relOid,
6767                                                            Oid oldNspOid, Oid newNspOid,
6768                                                            bool hasDependEntry)
6769 {
6770         HeapTuple       classTup;
6771         Form_pg_class classForm;
6772
6773         classTup = SearchSysCacheCopy(RELOID,
6774                                                                   ObjectIdGetDatum(relOid),
6775                                                                   0, 0, 0);
6776         if (!HeapTupleIsValid(classTup))
6777                 elog(ERROR, "cache lookup failed for relation %u", relOid);
6778         classForm = (Form_pg_class) GETSTRUCT(classTup);
6779
6780         Assert(classForm->relnamespace == oldNspOid);
6781
6782         /* check for duplicate name (more friendly than unique-index failure) */
6783         if (get_relname_relid(NameStr(classForm->relname),
6784                                                   newNspOid) != InvalidOid)
6785                 ereport(ERROR,
6786                                 (errcode(ERRCODE_DUPLICATE_TABLE),
6787                                  errmsg("relation \"%s\" already exists in schema \"%s\"",
6788                                                 NameStr(classForm->relname),
6789                                                 get_namespace_name(newNspOid))));
6790
6791         /* classTup is a copy, so OK to scribble on */
6792         classForm->relnamespace = newNspOid;
6793
6794         simple_heap_update(classRel, &classTup->t_self, classTup);
6795         CatalogUpdateIndexes(classRel, classTup);
6796
6797         /* Update dependency on schema if caller said so */
6798         if (hasDependEntry &&
6799                 changeDependencyFor(RelationRelationId, relOid,
6800                                                         NamespaceRelationId, oldNspOid, newNspOid) != 1)
6801                 elog(ERROR, "failed to change schema dependency for relation \"%s\"",
6802                          NameStr(classForm->relname));
6803
6804         heap_freetuple(classTup);
6805 }
6806
6807 /*
6808  * Move all indexes for the specified relation to another namespace.
6809  *
6810  * Note: we assume adequate permission checking was done by the caller,
6811  * and that the caller has a suitable lock on the owning relation.
6812  */
6813 static void
6814 AlterIndexNamespaces(Relation classRel, Relation rel,
6815                                          Oid oldNspOid, Oid newNspOid)
6816 {
6817         List       *indexList;
6818         ListCell   *l;
6819
6820         indexList = RelationGetIndexList(rel);
6821
6822         foreach(l, indexList)
6823         {
6824                 Oid                     indexOid = lfirst_oid(l);
6825
6826                 /*
6827                  * Note: currently, the index will not have its own dependency on the
6828                  * namespace, so we don't need to do changeDependencyFor(). There's no
6829                  * rowtype in pg_type, either.
6830                  */
6831                 AlterRelationNamespaceInternal(classRel, indexOid,
6832                                                                            oldNspOid, newNspOid,
6833                                                                            false);
6834         }
6835
6836         list_free(indexList);
6837 }
6838
6839 /*
6840  * Move all SERIAL-column sequences of the specified relation to another
6841  * namespace.
6842  *
6843  * Note: we assume adequate permission checking was done by the caller,
6844  * and that the caller has a suitable lock on the owning relation.
6845  */
6846 static void
6847 AlterSeqNamespaces(Relation classRel, Relation rel,
6848                                    Oid oldNspOid, Oid newNspOid, const char *newNspName)
6849 {
6850         Relation        depRel;
6851         SysScanDesc scan;
6852         ScanKeyData key[2];
6853         HeapTuple       tup;
6854
6855         /*
6856          * SERIAL sequences are those having an internal dependency on one of the
6857          * table's columns (we don't care *which* column, exactly).
6858          */
6859         depRel = heap_open(DependRelationId, AccessShareLock);
6860
6861         ScanKeyInit(&key[0],
6862                                 Anum_pg_depend_refclassid,
6863                                 BTEqualStrategyNumber, F_OIDEQ,
6864                                 ObjectIdGetDatum(RelationRelationId));
6865         ScanKeyInit(&key[1],
6866                                 Anum_pg_depend_refobjid,
6867                                 BTEqualStrategyNumber, F_OIDEQ,
6868                                 ObjectIdGetDatum(RelationGetRelid(rel)));
6869         /* we leave refobjsubid unspecified */
6870
6871         scan = systable_beginscan(depRel, DependReferenceIndexId, true,
6872                                                           SnapshotNow, 2, key);
6873
6874         while (HeapTupleIsValid(tup = systable_getnext(scan)))
6875         {
6876                 Form_pg_depend depForm = (Form_pg_depend) GETSTRUCT(tup);
6877                 Relation        seqRel;
6878
6879                 /* skip dependencies other than internal dependencies on columns */
6880                 if (depForm->refobjsubid == 0 ||
6881                         depForm->classid != RelationRelationId ||
6882                         depForm->objsubid != 0 ||
6883                         depForm->deptype != DEPENDENCY_INTERNAL)
6884                         continue;
6885
6886                 /* Use relation_open just in case it's an index */
6887                 seqRel = relation_open(depForm->objid, AccessExclusiveLock);
6888
6889                 /* skip non-sequence relations */
6890                 if (RelationGetForm(seqRel)->relkind != RELKIND_SEQUENCE)
6891                 {
6892                         /* No need to keep the lock */
6893                         relation_close(seqRel, AccessExclusiveLock);
6894                         continue;
6895                 }
6896
6897                 /* Fix the pg_class and pg_depend entries */
6898                 AlterRelationNamespaceInternal(classRel, depForm->objid,
6899                                                                            oldNspOid, newNspOid,
6900                                                                            true);
6901
6902                 /*
6903                  * Sequences have entries in pg_type. We need to be careful to move
6904                  * them to the new namespace, too.
6905                  */
6906                 AlterTypeNamespaceInternal(RelationGetForm(seqRel)->reltype,
6907                                                                    newNspOid, false);
6908
6909                 /* Now we can close it.  Keep the lock till end of transaction. */
6910                 relation_close(seqRel, NoLock);
6911         }
6912
6913         systable_endscan(scan);
6914
6915         relation_close(depRel, AccessShareLock);
6916 }
6917
6918
6919 /*
6920  * This code supports
6921  *      CREATE TEMP TABLE ... ON COMMIT { DROP | PRESERVE ROWS | DELETE ROWS }
6922  *
6923  * Because we only support this for TEMP tables, it's sufficient to remember
6924  * the state in a backend-local data structure.
6925  */
6926
6927 /*
6928  * Register a newly-created relation's ON COMMIT action.
6929  */
6930 void
6931 register_on_commit_action(Oid relid, OnCommitAction action)
6932 {
6933         OnCommitItem *oc;
6934         MemoryContext oldcxt;
6935
6936         /*
6937          * We needn't bother registering the relation unless there is an ON COMMIT
6938          * action we need to take.
6939          */
6940         if (action == ONCOMMIT_NOOP || action == ONCOMMIT_PRESERVE_ROWS)
6941                 return;
6942
6943         oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
6944
6945         oc = (OnCommitItem *) palloc(sizeof(OnCommitItem));
6946         oc->relid = relid;
6947         oc->oncommit = action;
6948         oc->creating_subid = GetCurrentSubTransactionId();
6949         oc->deleting_subid = InvalidSubTransactionId;
6950
6951         on_commits = lcons(oc, on_commits);
6952
6953         MemoryContextSwitchTo(oldcxt);
6954 }
6955
6956 /*
6957  * Unregister any ON COMMIT action when a relation is deleted.
6958  *
6959  * Actually, we only mark the OnCommitItem entry as to be deleted after commit.
6960  */
6961 void
6962 remove_on_commit_action(Oid relid)
6963 {
6964         ListCell   *l;
6965
6966         foreach(l, on_commits)
6967         {
6968                 OnCommitItem *oc = (OnCommitItem *) lfirst(l);
6969
6970                 if (oc->relid == relid)
6971                 {
6972                         oc->deleting_subid = GetCurrentSubTransactionId();
6973                         break;
6974                 }
6975         }
6976 }
6977
6978 /*
6979  * Perform ON COMMIT actions.
6980  *
6981  * This is invoked just before actually committing, since it's possible
6982  * to encounter errors.
6983  */
6984 void
6985 PreCommit_on_commit_actions(void)
6986 {
6987         ListCell   *l;
6988         List       *oids_to_truncate = NIL;
6989
6990         foreach(l, on_commits)
6991         {
6992                 OnCommitItem *oc = (OnCommitItem *) lfirst(l);
6993
6994                 /* Ignore entry if already dropped in this xact */
6995                 if (oc->deleting_subid != InvalidSubTransactionId)
6996                         continue;
6997
6998                 switch (oc->oncommit)
6999                 {
7000                         case ONCOMMIT_NOOP:
7001                         case ONCOMMIT_PRESERVE_ROWS:
7002                                 /* Do nothing (there shouldn't be such entries, actually) */
7003                                 break;
7004                         case ONCOMMIT_DELETE_ROWS:
7005                                 oids_to_truncate = lappend_oid(oids_to_truncate, oc->relid);
7006                                 break;
7007                         case ONCOMMIT_DROP:
7008                                 {
7009                                         ObjectAddress object;
7010
7011                                         object.classId = RelationRelationId;
7012                                         object.objectId = oc->relid;
7013                                         object.objectSubId = 0;
7014                                         performDeletion(&object, DROP_CASCADE);
7015
7016                                         /*
7017                                          * Note that table deletion will call
7018                                          * remove_on_commit_action, so the entry should get marked
7019                                          * as deleted.
7020                                          */
7021                                         Assert(oc->deleting_subid != InvalidSubTransactionId);
7022                                         break;
7023                                 }
7024                 }
7025         }
7026         if (oids_to_truncate != NIL)
7027         {
7028                 heap_truncate(oids_to_truncate);
7029                 CommandCounterIncrement();              /* XXX needed? */
7030         }
7031 }
7032
7033 /*
7034  * Post-commit or post-abort cleanup for ON COMMIT management.
7035  *
7036  * All we do here is remove no-longer-needed OnCommitItem entries.
7037  *
7038  * During commit, remove entries that were deleted during this transaction;
7039  * during abort, remove those created during this transaction.
7040  */
7041 void
7042 AtEOXact_on_commit_actions(bool isCommit)
7043 {
7044         ListCell   *cur_item;
7045         ListCell   *prev_item;
7046
7047         prev_item = NULL;
7048         cur_item = list_head(on_commits);
7049
7050         while (cur_item != NULL)
7051         {
7052                 OnCommitItem *oc = (OnCommitItem *) lfirst(cur_item);
7053
7054                 if (isCommit ? oc->deleting_subid != InvalidSubTransactionId :
7055                         oc->creating_subid != InvalidSubTransactionId)
7056                 {
7057                         /* cur_item must be removed */
7058                         on_commits = list_delete_cell(on_commits, cur_item, prev_item);
7059                         pfree(oc);
7060                         if (prev_item)
7061                                 cur_item = lnext(prev_item);
7062                         else
7063                                 cur_item = list_head(on_commits);
7064                 }
7065                 else
7066                 {
7067                         /* cur_item must be preserved */
7068                         oc->creating_subid = InvalidSubTransactionId;
7069                         oc->deleting_subid = InvalidSubTransactionId;
7070                         prev_item = cur_item;
7071                         cur_item = lnext(prev_item);
7072                 }
7073         }
7074 }
7075
7076 /*
7077  * Post-subcommit or post-subabort cleanup for ON COMMIT management.
7078  *
7079  * During subabort, we can immediately remove entries created during this
7080  * subtransaction.      During subcommit, just relabel entries marked during
7081  * this subtransaction as being the parent's responsibility.
7082  */
7083 void
7084 AtEOSubXact_on_commit_actions(bool isCommit, SubTransactionId mySubid,
7085                                                           SubTransactionId parentSubid)
7086 {
7087         ListCell   *cur_item;
7088         ListCell   *prev_item;
7089
7090         prev_item = NULL;
7091         cur_item = list_head(on_commits);
7092
7093         while (cur_item != NULL)
7094         {
7095                 OnCommitItem *oc = (OnCommitItem *) lfirst(cur_item);
7096
7097                 if (!isCommit && oc->creating_subid == mySubid)
7098                 {
7099                         /* cur_item must be removed */
7100                         on_commits = list_delete_cell(on_commits, cur_item, prev_item);
7101                         pfree(oc);
7102                         if (prev_item)
7103                                 cur_item = lnext(prev_item);
7104                         else
7105                                 cur_item = list_head(on_commits);
7106                 }
7107                 else
7108                 {
7109                         /* cur_item must be preserved */
7110                         if (oc->creating_subid == mySubid)
7111                                 oc->creating_subid = parentSubid;
7112                         if (oc->deleting_subid == mySubid)
7113                                 oc->deleting_subid = isCommit ? parentSubid : InvalidSubTransactionId;
7114                         prev_item = cur_item;
7115                         cur_item = lnext(prev_item);
7116                 }
7117         }
7118 }