granicus.if.org Git - postgresql/blob - src/backend/executor/functions.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * functions.c
   4  *        Execution of SQL-language functions
   5  *
   6  * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        src/backend/executor/functions.c
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include "access/htup_details.h"
  18 #include "access/xact.h"
  19 #include "catalog/pg_proc.h"
  20 #include "catalog/pg_type.h"
  21 #include "executor/functions.h"
  22 #include "funcapi.h"
  23 #include "miscadmin.h"
  24 #include "nodes/makefuncs.h"
  25 #include "nodes/nodeFuncs.h"
  26 #include "parser/parse_coerce.h"
  27 #include "parser/parse_func.h"
  28 #include "storage/proc.h"
  29 #include "tcop/utility.h"
  30 #include "utils/builtins.h"
  31 #include "utils/datum.h"
  32 #include "utils/lsyscache.h"
  33 #include "utils/memutils.h"
  34 #include "utils/snapmgr.h"
  35 #include "utils/syscache.h"
  36
  37
  38 /*
  39  * Specialized DestReceiver for collecting query output in a SQL function
  40  */
  41 typedef struct
  42 {
  43         DestReceiver pub;                       /* publicly-known function pointers */
  44         Tuplestorestate *tstore;        /* where to put result tuples */
  45         MemoryContext cxt;                      /* context containing tstore */
  46         JunkFilter *filter;                     /* filter to convert tuple type */
  47 } DR_sqlfunction;
  48
  49 /*
  50  * We have an execution_state record for each query in a function.  Each
  51  * record contains a plantree for its query.  If the query is currently in
  52  * F_EXEC_RUN state then there's a QueryDesc too.
  53  *
  54  * The "next" fields chain together all the execution_state records generated
  55  * from a single original parsetree.  (There will only be more than one in
  56  * case of rule expansion of the original parsetree.)
  57  */
  58 typedef enum
  59 {
  60         F_EXEC_START, F_EXEC_RUN, F_EXEC_DONE
  61 } ExecStatus;
  62
  63 typedef struct execution_state
  64 {
  65         struct execution_state *next;
  66         ExecStatus      status;
  67         bool            setsResult;             /* true if this query produces func's result */
  68         bool            lazyEval;               /* true if should fetch one row at a time */
  69         PlannedStmt *stmt;                      /* plan for this query */
  70         QueryDesc  *qd;                         /* null unless status == RUN */
  71 } execution_state;
  72
  73
  74 /*
  75  * An SQLFunctionCache record is built during the first call,
  76  * and linked to from the fn_extra field of the FmgrInfo struct.
  77  *
  78  * Note that currently this has only the lifespan of the calling query.
  79  * Someday we should rewrite this code to use plancache.c to save parse/plan
  80  * results for longer than that.
  81  *
  82  * Physically, though, the data has the lifespan of the FmgrInfo that's used
  83  * to call the function, and there are cases (particularly with indexes)
  84  * where the FmgrInfo might survive across transactions.  We cannot assume
  85  * that the parse/plan trees are good for longer than the (sub)transaction in
  86  * which parsing was done, so we must mark the record with the LXID/subxid of
  87  * its creation time, and regenerate everything if that's obsolete.  To avoid
  88  * memory leakage when we do have to regenerate things, all the data is kept
  89  * in a sub-context of the FmgrInfo's fn_mcxt.
  90  */
  91 typedef struct
  92 {
  93         char       *fname;                      /* function name (for error msgs) */
  94         char       *src;                        /* function body text (for error msgs) */
  95
  96         SQLFunctionParseInfoPtr pinfo;  /* data for parser callback hooks */
  97
  98         Oid                     rettype;                /* actual return type */
  99         int16           typlen;                 /* length of the return type */
 100         bool            typbyval;               /* true if return type is pass by value */
 101         bool            returnsSet;             /* true if returning multiple rows */
 102         bool            returnsTuple;   /* true if returning whole tuple result */
 103         bool            shutdown_reg;   /* true if registered shutdown callback */
 104         bool            readonly_func;  /* true to run in "read only" mode */
 105         bool            lazyEval;               /* true if using lazyEval for result query */
 106
 107         ParamListInfo paramLI;          /* Param list representing current args */
 108
 109         Tuplestorestate *tstore;        /* where we accumulate result tuples */
 110
 111         JunkFilter *junkFilter;         /* will be NULL if function returns VOID */
 112
 113         /*
 114          * func_state is a List of execution_state records, each of which is the
 115          * first for its original parsetree, with any additional records chained
 116          * to it via the "next" fields.  This sublist structure is needed to keep
 117          * track of where the original query boundaries are.
 118          */
 119         List       *func_state;
 120
 121         MemoryContext fcontext;         /* memory context holding this struct and all
 122                                                                  * subsidiary data */
 123
 124         LocalTransactionId lxid;        /* lxid in which cache was made */
 125         SubTransactionId subxid;        /* subxid in which cache was made */
 126 } SQLFunctionCache;
 127
 128 typedef SQLFunctionCache *SQLFunctionCachePtr;
 129
 130 /*
 131  * Data structure needed by the parser callback hooks to resolve parameter
 132  * references during parsing of a SQL function's body.  This is separate from
 133  * SQLFunctionCache since we sometimes do parsing separately from execution.
 134  */
 135 typedef struct SQLFunctionParseInfo
 136 {
 137         char       *fname;                      /* function's name */
 138         int                     nargs;                  /* number of input arguments */
 139         Oid                *argtypes;           /* resolved types of input arguments */
 140         char      **argnames;           /* names of input arguments; NULL if none */
 141         /* Note that argnames[i] can be NULL, if some args are unnamed */
 142         Oid                     collation;              /* function's input collation, if known */
 143 }                       SQLFunctionParseInfo;
 144
 145
 146 /* non-export function prototypes */
 147 static Node *sql_fn_param_ref(ParseState *pstate, ParamRef *pref);
 148 static Node *sql_fn_post_column_ref(ParseState *pstate,
 149                                            ColumnRef *cref, Node *var);
 150 static Node *sql_fn_make_param(SQLFunctionParseInfoPtr pinfo,
 151                                   int paramno, int location);
 152 static Node *sql_fn_resolve_param_name(SQLFunctionParseInfoPtr pinfo,
 153                                                   const char *paramname, int location);
 154 static List *init_execution_state(List *queryTree_list,
 155                                          SQLFunctionCachePtr fcache,
 156                                          bool lazyEvalOK);
 157 static void init_sql_fcache(FmgrInfo *finfo, Oid collation, bool lazyEvalOK);
 158 static void postquel_start(execution_state *es, SQLFunctionCachePtr fcache);
 159 static bool postquel_getnext(execution_state *es, SQLFunctionCachePtr fcache);
 160 static void postquel_end(execution_state *es);
 161 static void postquel_sub_params(SQLFunctionCachePtr fcache,
 162                                         FunctionCallInfo fcinfo);
 163 static Datum postquel_get_single_result(TupleTableSlot *slot,
 164                                                    FunctionCallInfo fcinfo,
 165                                                    SQLFunctionCachePtr fcache,
 166                                                    MemoryContext resultcontext);
 167 static void sql_exec_error_callback(void *arg);
 168 static void ShutdownSQLFunction(Datum arg);
 169 static void sqlfunction_startup(DestReceiver *self, int operation, TupleDesc typeinfo);
 170 static bool sqlfunction_receive(TupleTableSlot *slot, DestReceiver *self);
 171 static void sqlfunction_shutdown(DestReceiver *self);
 172 static void sqlfunction_destroy(DestReceiver *self);
 173
 174
 175 /*
 176  * Prepare the SQLFunctionParseInfo struct for parsing a SQL function body
 177  *
 178  * This includes resolving actual types of polymorphic arguments.
 179  *
 180  * call_expr can be passed as NULL, but then we will fail if there are any
 181  * polymorphic arguments.
 182  */
 183 SQLFunctionParseInfoPtr
 184 prepare_sql_fn_parse_info(HeapTuple procedureTuple,
 185                                                   Node *call_expr,
 186                                                   Oid inputCollation)
 187 {
 188         SQLFunctionParseInfoPtr pinfo;
 189         Form_pg_proc procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple);
 190         int                     nargs;
 191
 192         pinfo = (SQLFunctionParseInfoPtr) palloc0(sizeof(SQLFunctionParseInfo));
 193
 194         /* Function's name (only) can be used to qualify argument names */
 195         pinfo->fname = pstrdup(NameStr(procedureStruct->proname));
 196
 197         /* Save the function's input collation */
 198         pinfo->collation = inputCollation;
 199
 200         /*
 201          * Copy input argument types from the pg_proc entry, then resolve any
 202          * polymorphic types.
 203          */
 204         pinfo->nargs = nargs = procedureStruct->pronargs;
 205         if (nargs > 0)
 206         {
 207                 Oid                *argOidVect;
 208                 int                     argnum;
 209
 210                 argOidVect = (Oid *) palloc(nargs * sizeof(Oid));
 211                 memcpy(argOidVect,
 212                            procedureStruct->proargtypes.values,
 213                            nargs * sizeof(Oid));
 214
 215                 for (argnum = 0; argnum < nargs; argnum++)
 216                 {
 217                         Oid                     argtype = argOidVect[argnum];
 218
 219                         if (IsPolymorphicType(argtype))
 220                         {
 221                                 argtype = get_call_expr_argtype(call_expr, argnum);
 222                                 if (argtype == InvalidOid)
 223                                         ereport(ERROR,
 224                                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
 225                                                          errmsg("could not determine actual type of argument declared %s",
 226                                                                         format_type_be(argOidVect[argnum]))));
 227                                 argOidVect[argnum] = argtype;
 228                         }
 229                 }
 230
 231                 pinfo->argtypes = argOidVect;
 232         }
 233
 234         /*
 235          * Collect names of arguments, too, if any
 236          */
 237         if (nargs > 0)
 238         {
 239                 Datum           proargnames;
 240                 Datum           proargmodes;
 241                 int                     n_arg_names;
 242                 bool            isNull;
 243
 244                 proargnames = SysCacheGetAttr(PROCNAMEARGSNSP, procedureTuple,
 245                                                                           Anum_pg_proc_proargnames,
 246                                                                           &isNull);
 247                 if (isNull)
 248                         proargnames = PointerGetDatum(NULL);    /* just to be sure */
 249
 250                 proargmodes = SysCacheGetAttr(PROCNAMEARGSNSP, procedureTuple,
 251                                                                           Anum_pg_proc_proargmodes,
 252                                                                           &isNull);
 253                 if (isNull)
 254                         proargmodes = PointerGetDatum(NULL);    /* just to be sure */
 255
 256                 n_arg_names = get_func_input_arg_names(proargnames, proargmodes,
 257                                                                                            &pinfo->argnames);
 258
 259                 /* Paranoia: ignore the result if too few array entries */
 260                 if (n_arg_names < nargs)
 261                         pinfo->argnames = NULL;
 262         }
 263         else
 264                 pinfo->argnames = NULL;
 265
 266         return pinfo;
 267 }
 268
 269 /*
 270  * Parser setup hook for parsing a SQL function body.
 271  */
 272 void
 273 sql_fn_parser_setup(struct ParseState *pstate, SQLFunctionParseInfoPtr pinfo)
 274 {
 275         pstate->p_pre_columnref_hook = NULL;
 276         pstate->p_post_columnref_hook = sql_fn_post_column_ref;
 277         pstate->p_paramref_hook = sql_fn_param_ref;
 278         /* no need to use p_coerce_param_hook */
 279         pstate->p_ref_hook_state = (void *) pinfo;
 280 }
 281
 282 /*
 283  * sql_fn_post_column_ref               parser callback for ColumnRefs
 284  */
 285 static Node *
 286 sql_fn_post_column_ref(ParseState *pstate, ColumnRef *cref, Node *var)
 287 {
 288         SQLFunctionParseInfoPtr pinfo = (SQLFunctionParseInfoPtr) pstate->p_ref_hook_state;
 289         int                     nnames;
 290         Node       *field1;
 291         Node       *subfield = NULL;
 292         const char *name1;
 293         const char *name2 = NULL;
 294         Node       *param;
 295
 296         /*
 297          * Never override a table-column reference.  This corresponds to
 298          * considering the parameter names to appear in a scope outside the
 299          * individual SQL commands, which is what we want.
 300          */
 301         if (var != NULL)
 302                 return NULL;
 303
 304         /*----------
 305          * The allowed syntaxes are:
 306          *
 307          * A            A = parameter name
 308          * A.B          A = function name, B = parameter name
 309          *                      OR: A = record-typed parameter name, B = field name
 310          *                      (the first possibility takes precedence)
 311          * A.B.C        A = function name, B = record-typed parameter name,
 312          *                      C = field name
 313          * A.*          Whole-row reference to composite parameter A.
 314          * A.B.*        Same, with A = function name, B = parameter name
 315          *
 316          * Here, it's sufficient to ignore the "*" in the last two cases --- the
 317          * main parser will take care of expanding the whole-row reference.
 318          *----------
 319          */
 320         nnames = list_length(cref->fields);
 321
 322         if (nnames > 3)
 323                 return NULL;
 324
 325         if (IsA(llast(cref->fields), A_Star))
 326                 nnames--;
 327
 328         field1 = (Node *) linitial(cref->fields);
 329         Assert(IsA(field1, String));
 330         name1 = strVal(field1);
 331         if (nnames > 1)
 332         {
 333                 subfield = (Node *) lsecond(cref->fields);
 334                 Assert(IsA(subfield, String));
 335                 name2 = strVal(subfield);
 336         }
 337
 338         if (nnames == 3)
 339         {
 340                 /*
 341                  * Three-part name: if the first part doesn't match the function name,
 342                  * we can fail immediately. Otherwise, look up the second part, and
 343                  * take the third part to be a field reference.
 344                  */
 345                 if (strcmp(name1, pinfo->fname) != 0)
 346                         return NULL;
 347
 348                 param = sql_fn_resolve_param_name(pinfo, name2, cref->location);
 349
 350                 subfield = (Node *) lthird(cref->fields);
 351                 Assert(IsA(subfield, String));
 352         }
 353         else if (nnames == 2 && strcmp(name1, pinfo->fname) == 0)
 354         {
 355                 /*
 356                  * Two-part name with first part matching function name: first see if
 357                  * second part matches any parameter name.
 358                  */
 359                 param = sql_fn_resolve_param_name(pinfo, name2, cref->location);
 360
 361                 if (param)
 362                 {
 363                         /* Yes, so this is a parameter reference, no subfield */
 364                         subfield = NULL;
 365                 }
 366                 else
 367                 {
 368                         /* No, so try to match as parameter name and subfield */
 369                         param = sql_fn_resolve_param_name(pinfo, name1, cref->location);
 370                 }
 371         }
 372         else
 373         {
 374                 /* Single name, or parameter name followed by subfield */
 375                 param = sql_fn_resolve_param_name(pinfo, name1, cref->location);
 376         }
 377
 378         if (!param)
 379                 return NULL;                    /* No match */
 380
 381         if (subfield)
 382         {
 383                 /*
 384                  * Must be a reference to a field of a composite parameter; otherwise
 385                  * ParseFuncOrColumn will return NULL, and we'll fail back at the
 386                  * caller.
 387                  */
 388                 param = ParseFuncOrColumn(pstate,
 389                                                                   list_make1(subfield),
 390                                                                   list_make1(param),
 391                                                                   pstate->p_last_srf,
 392                                                                   NULL,
 393                                                                   false,
 394                                                                   cref->location);
 395         }
 396
 397         return param;
 398 }
 399
 400 /*
 401  * sql_fn_param_ref             parser callback for ParamRefs ($n symbols)
 402  */
 403 static Node *
 404 sql_fn_param_ref(ParseState *pstate, ParamRef *pref)
 405 {
 406         SQLFunctionParseInfoPtr pinfo = (SQLFunctionParseInfoPtr) pstate->p_ref_hook_state;
 407         int                     paramno = pref->number;
 408
 409         /* Check parameter number is valid */
 410         if (paramno <= 0 || paramno > pinfo->nargs)
 411                 return NULL;                    /* unknown parameter number */
 412
 413         return sql_fn_make_param(pinfo, paramno, pref->location);
 414 }
 415
 416 /*
 417  * sql_fn_make_param            construct a Param node for the given paramno
 418  */
 419 static Node *
 420 sql_fn_make_param(SQLFunctionParseInfoPtr pinfo,
 421                                   int paramno, int location)
 422 {
 423         Param      *param;
 424
 425         param = makeNode(Param);
 426         param->paramkind = PARAM_EXTERN;
 427         param->paramid = paramno;
 428         param->paramtype = pinfo->argtypes[paramno - 1];
 429         param->paramtypmod = -1;
 430         param->paramcollid = get_typcollation(param->paramtype);
 431         param->location = location;
 432
 433         /*
 434          * If we have a function input collation, allow it to override the
 435          * type-derived collation for parameter symbols.  (XXX perhaps this should
 436          * not happen if the type collation is not default?)
 437          */
 438         if (OidIsValid(pinfo->collation) && OidIsValid(param->paramcollid))
 439                 param->paramcollid = pinfo->collation;
 440
 441         return (Node *) param;
 442 }
 443
 444 /*
 445  * Search for a function parameter of the given name; if there is one,
 446  * construct and return a Param node for it.  If not, return NULL.
 447  * Helper function for sql_fn_post_column_ref.
 448  */
 449 static Node *
 450 sql_fn_resolve_param_name(SQLFunctionParseInfoPtr pinfo,
 451                                                   const char *paramname, int location)
 452 {
 453         int                     i;
 454
 455         if (pinfo->argnames == NULL)
 456                 return NULL;
 457
 458         for (i = 0; i < pinfo->nargs; i++)
 459         {
 460                 if (pinfo->argnames[i] && strcmp(pinfo->argnames[i], paramname) == 0)
 461                         return sql_fn_make_param(pinfo, i + 1, location);
 462         }
 463
 464         return NULL;
 465 }
 466
 467 /*
 468  * Set up the per-query execution_state records for a SQL function.
 469  *
 470  * The input is a List of Lists of parsed and rewritten, but not planned,
 471  * querytrees.  The sublist structure denotes the original query boundaries.
 472  */
 473 static List *
 474 init_execution_state(List *queryTree_list,
 475                                          SQLFunctionCachePtr fcache,
 476                                          bool lazyEvalOK)
 477 {
 478         List       *eslist = NIL;
 479         execution_state *lasttages = NULL;
 480         ListCell   *lc1;
 481
 482         foreach(lc1, queryTree_list)
 483         {
 484                 List       *qtlist = lfirst_node(List, lc1);
 485                 execution_state *firstes = NULL;
 486                 execution_state *preves = NULL;
 487                 ListCell   *lc2;
 488
 489                 foreach(lc2, qtlist)
 490                 {
 491                         Query      *queryTree = lfirst_node(Query, lc2);
 492                         PlannedStmt *stmt;
 493                         execution_state *newes;
 494
 495                         /* Plan the query if needed */
 496                         if (queryTree->commandType == CMD_UTILITY)
 497                         {
 498                                 /* Utility commands require no planning. */
 499                                 stmt = makeNode(PlannedStmt);
 500                                 stmt->commandType = CMD_UTILITY;
 501                                 stmt->canSetTag = queryTree->canSetTag;
 502                                 stmt->utilityStmt = queryTree->utilityStmt;
 503                                 stmt->stmt_location = queryTree->stmt_location;
 504                                 stmt->stmt_len = queryTree->stmt_len;
 505                         }
 506                         else
 507                                 stmt = pg_plan_query(queryTree,
 508                                                                          CURSOR_OPT_PARALLEL_OK,
 509                                                                          NULL);
 510
 511                         /*
 512                          * Precheck all commands for validity in a function.  This should
 513                          * generally match the restrictions spi.c applies.
 514                          */
 515                         if (stmt->commandType == CMD_UTILITY)
 516                         {
 517                                 if (IsA(stmt->utilityStmt, CopyStmt) &&
 518                                         ((CopyStmt *) stmt->utilityStmt)->filename == NULL)
 519                                         ereport(ERROR,
 520                                                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 521                                                          errmsg("cannot COPY to/from client in a SQL function")));
 522
 523                                 if (IsA(stmt->utilityStmt, TransactionStmt))
 524                                         ereport(ERROR,
 525                                                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 526                                         /* translator: %s is a SQL statement name */
 527                                                          errmsg("%s is not allowed in a SQL function",
 528                                                                         CreateCommandTag(stmt->utilityStmt))));
 529                         }
 530
 531                         if (fcache->readonly_func && !CommandIsReadOnly(stmt))
 532                                 ereport(ERROR,
 533                                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 534                                 /* translator: %s is a SQL statement name */
 535                                                  errmsg("%s is not allowed in a non-volatile function",
 536                                                                 CreateCommandTag((Node *) stmt))));
 537
 538                         if (IsInParallelMode() && !CommandIsReadOnly(stmt))
 539                                 PreventCommandIfParallelMode(CreateCommandTag((Node *) stmt));
 540
 541                         /* OK, build the execution_state for this query */
 542                         newes = (execution_state *) palloc(sizeof(execution_state));
 543                         if (preves)
 544                                 preves->next = newes;
 545                         else
 546                                 firstes = newes;
 547
 548                         newes->next = NULL;
 549                         newes->status = F_EXEC_START;
 550                         newes->setsResult = false;      /* might change below */
 551                         newes->lazyEval = false;        /* might change below */
 552                         newes->stmt = stmt;
 553                         newes->qd = NULL;
 554
 555                         if (queryTree->canSetTag)
 556                                 lasttages = newes;
 557
 558                         preves = newes;
 559                 }
 560
 561                 eslist = lappend(eslist, firstes);
 562         }
 563
 564         /*
 565          * Mark the last canSetTag query as delivering the function result; then,
 566          * if it is a plain SELECT, mark it for lazy evaluation. If it's not a
 567          * SELECT we must always run it to completion.
 568          *
 569          * Note: at some point we might add additional criteria for whether to use
 570          * lazy eval.  However, we should prefer to use it whenever the function
 571          * doesn't return set, since fetching more than one row is useless in that
 572          * case.
 573          *
 574          * Note: don't set setsResult if the function returns VOID, as evidenced
 575          * by not having made a junkfilter.  This ensures we'll throw away any
 576          * output from the last statement in such a function.
 577          */
 578         if (lasttages && fcache->junkFilter)
 579         {
 580                 lasttages->setsResult = true;
 581                 if (lazyEvalOK &&
 582                         lasttages->stmt->commandType == CMD_SELECT &&
 583                         !lasttages->stmt->hasModifyingCTE)
 584                         fcache->lazyEval = lasttages->lazyEval = true;
 585         }
 586
 587         return eslist;
 588 }
 589
 590 /*
 591  * Initialize the SQLFunctionCache for a SQL function
 592  */
 593 static void
 594 init_sql_fcache(FmgrInfo *finfo, Oid collation, bool lazyEvalOK)
 595 {
 596         Oid                     foid = finfo->fn_oid;
 597         MemoryContext fcontext;
 598         MemoryContext oldcontext;
 599         Oid                     rettype;
 600         HeapTuple       procedureTuple;
 601         Form_pg_proc procedureStruct;
 602         SQLFunctionCachePtr fcache;
 603         List       *raw_parsetree_list;
 604         List       *queryTree_list;
 605         List       *flat_query_list;
 606         ListCell   *lc;
 607         Datum           tmp;
 608         bool            isNull;
 609
 610         /*
 611          * Create memory context that holds all the SQLFunctionCache data.  It
 612          * must be a child of whatever context holds the FmgrInfo.
 613          */
 614         fcontext = AllocSetContextCreate(finfo->fn_mcxt,
 615                                                                          "SQL function",
 616                                                                          ALLOCSET_DEFAULT_SIZES);
 617
 618         oldcontext = MemoryContextSwitchTo(fcontext);
 619
 620         /*
 621          * Create the struct proper, link it to fcontext and fn_extra.  Once this
 622          * is done, we'll be able to recover the memory after failure, even if the
 623          * FmgrInfo is long-lived.
 624          */
 625         fcache = (SQLFunctionCachePtr) palloc0(sizeof(SQLFunctionCache));
 626         fcache->fcontext = fcontext;
 627         finfo->fn_extra = (void *) fcache;
 628
 629         /*
 630          * get the procedure tuple corresponding to the given function Oid
 631          */
 632         procedureTuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(foid));
 633         if (!HeapTupleIsValid(procedureTuple))
 634                 elog(ERROR, "cache lookup failed for function %u", foid);
 635         procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple);
 636
 637         /*
 638          * copy function name immediately for use by error reporting callback, and
 639          * for use as memory context identifier
 640          */
 641         fcache->fname = pstrdup(NameStr(procedureStruct->proname));
 642         MemoryContextSetIdentifier(fcontext, fcache->fname);
 643
 644         /*
 645          * get the result type from the procedure tuple, and check for polymorphic
 646          * result type; if so, find out the actual result type.
 647          */
 648         rettype = procedureStruct->prorettype;
 649
 650         if (IsPolymorphicType(rettype))
 651         {
 652                 rettype = get_fn_expr_rettype(finfo);
 653                 if (rettype == InvalidOid)      /* this probably should not happen */
 654                         ereport(ERROR,
 655                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
 656                                          errmsg("could not determine actual result type for function declared to return type %s",
 657                                                         format_type_be(procedureStruct->prorettype))));
 658         }
 659
 660         fcache->rettype = rettype;
 661
 662         /* Fetch the typlen and byval info for the result type */
 663         get_typlenbyval(rettype, &fcache->typlen, &fcache->typbyval);
 664
 665         /* Remember whether we're returning setof something */
 666         fcache->returnsSet = procedureStruct->proretset;
 667
 668         /* Remember if function is STABLE/IMMUTABLE */
 669         fcache->readonly_func =
 670                 (procedureStruct->provolatile != PROVOLATILE_VOLATILE);
 671
 672         /*
 673          * We need the actual argument types to pass to the parser.  Also make
 674          * sure that parameter symbols are considered to have the function's
 675          * resolved input collation.
 676          */
 677         fcache->pinfo = prepare_sql_fn_parse_info(procedureTuple,
 678                                                                                           finfo->fn_expr,
 679                                                                                           collation);
 680
 681         /*
 682          * And of course we need the function body text.
 683          */
 684         tmp = SysCacheGetAttr(PROCOID,
 685                                                   procedureTuple,
 686                                                   Anum_pg_proc_prosrc,
 687                                                   &isNull);
 688         if (isNull)
 689                 elog(ERROR, "null prosrc for function %u", foid);
 690         fcache->src = TextDatumGetCString(tmp);
 691
 692         /*
 693          * Parse and rewrite the queries in the function text.  Use sublists to
 694          * keep track of the original query boundaries.  But we also build a
 695          * "flat" list of the rewritten queries to pass to check_sql_fn_retval.
 696          * This is because the last canSetTag query determines the result type
 697          * independently of query boundaries --- and it might not be in the last
 698          * sublist, for example if the last query rewrites to DO INSTEAD NOTHING.
 699          * (It might not be unreasonable to throw an error in such a case, but
 700          * this is the historical behavior and it doesn't seem worth changing.)
 701          *
 702          * Note: since parsing and planning is done in fcontext, we will generate
 703          * a lot of cruft that lives as long as the fcache does.  This is annoying
 704          * but we'll not worry about it until the module is rewritten to use
 705          * plancache.c.
 706          */
 707         raw_parsetree_list = pg_parse_query(fcache->src);
 708
 709         queryTree_list = NIL;
 710         flat_query_list = NIL;
 711         foreach(lc, raw_parsetree_list)
 712         {
 713                 RawStmt    *parsetree = lfirst_node(RawStmt, lc);
 714                 List       *queryTree_sublist;
 715
 716                 queryTree_sublist = pg_analyze_and_rewrite_params(parsetree,
 717                                                                                                                   fcache->src,
 718                                                                                                                   (ParserSetupHook) sql_fn_parser_setup,
 719                                                                                                                   fcache->pinfo,
 720                                                                                                                   NULL);
 721                 queryTree_list = lappend(queryTree_list, queryTree_sublist);
 722                 flat_query_list = list_concat(flat_query_list,
 723                                                                           list_copy(queryTree_sublist));
 724         }
 725
 726         check_sql_fn_statements(flat_query_list);
 727
 728         /*
 729          * Check that the function returns the type it claims to.  Although in
 730          * simple cases this was already done when the function was defined, we
 731          * have to recheck because database objects used in the function's queries
 732          * might have changed type.  We'd have to do it anyway if the function had
 733          * any polymorphic arguments.
 734          *
 735          * Note: we set fcache->returnsTuple according to whether we are returning
 736          * the whole tuple result or just a single column.  In the latter case we
 737          * clear returnsTuple because we need not act different from the scalar
 738          * result case, even if it's a rowtype column.  (However, we have to force
 739          * lazy eval mode in that case; otherwise we'd need extra code to expand
 740          * the rowtype column into multiple columns, since we have no way to
 741          * notify the caller that it should do that.)
 742          *
 743          * check_sql_fn_retval will also construct a JunkFilter we can use to
 744          * coerce the returned rowtype to the desired form (unless the result type
 745          * is VOID, in which case there's nothing to coerce to).
 746          */
 747         fcache->returnsTuple = check_sql_fn_retval(foid,
 748                                                                                            rettype,
 749                                                                                            flat_query_list,
 750                                                                                            NULL,
 751                                                                                            &fcache->junkFilter);
 752
 753         if (fcache->returnsTuple)
 754         {
 755                 /* Make sure output rowtype is properly blessed */
 756                 BlessTupleDesc(fcache->junkFilter->jf_resultSlot->tts_tupleDescriptor);
 757         }
 758         else if (fcache->returnsSet && type_is_rowtype(fcache->rettype))
 759         {
 760                 /*
 761                  * Returning rowtype as if it were scalar --- materialize won't work.
 762                  * Right now it's sufficient to override any caller preference for
 763                  * materialize mode, but to add more smarts in init_execution_state
 764                  * about this, we'd probably need a three-way flag instead of bool.
 765                  */
 766                 lazyEvalOK = true;
 767         }
 768
 769         /* Finally, plan the queries */
 770         fcache->func_state = init_execution_state(queryTree_list,
 771                                                                                           fcache,
 772                                                                                           lazyEvalOK);
 773
 774         /* Mark fcache with time of creation to show it's valid */
 775         fcache->lxid = MyProc->lxid;
 776         fcache->subxid = GetCurrentSubTransactionId();
 777
 778         ReleaseSysCache(procedureTuple);
 779
 780         MemoryContextSwitchTo(oldcontext);
 781 }
 782
 783 /* Start up execution of one execution_state node */
 784 static void
 785 postquel_start(execution_state *es, SQLFunctionCachePtr fcache)
 786 {
 787         DestReceiver *dest;
 788
 789         Assert(es->qd == NULL);
 790
 791         /* Caller should have ensured a suitable snapshot is active */
 792         Assert(ActiveSnapshotSet());
 793
 794         /*
 795          * If this query produces the function result, send its output to the
 796          * tuplestore; else discard any output.
 797          */
 798         if (es->setsResult)
 799         {
 800                 DR_sqlfunction *myState;
 801
 802                 dest = CreateDestReceiver(DestSQLFunction);
 803                 /* pass down the needed info to the dest receiver routines */
 804                 myState = (DR_sqlfunction *) dest;
 805                 Assert(myState->pub.mydest == DestSQLFunction);
 806                 myState->tstore = fcache->tstore;
 807                 myState->cxt = CurrentMemoryContext;
 808                 myState->filter = fcache->junkFilter;
 809         }
 810         else
 811                 dest = None_Receiver;
 812
 813         es->qd = CreateQueryDesc(es->stmt,
 814                                                          fcache->src,
 815                                                          GetActiveSnapshot(),
 816                                                          InvalidSnapshot,
 817                                                          dest,
 818                                                          fcache->paramLI,
 819                                                          es->qd ? es->qd->queryEnv : NULL,
 820                                                          0);
 821
 822         /* Utility commands don't need Executor. */
 823         if (es->qd->operation != CMD_UTILITY)
 824         {
 825                 /*
 826                  * In lazyEval mode, do not let the executor set up an AfterTrigger
 827                  * context.  This is necessary not just an optimization, because we
 828                  * mustn't exit from the function execution with a stacked
 829                  * AfterTrigger level still active.  We are careful not to select
 830                  * lazyEval mode for any statement that could possibly queue triggers.
 831                  */
 832                 int                     eflags;
 833
 834                 if (es->lazyEval)
 835                         eflags = EXEC_FLAG_SKIP_TRIGGERS;
 836                 else
 837                         eflags = 0;                     /* default run-to-completion flags */
 838                 ExecutorStart(es->qd, eflags);
 839         }
 840
 841         es->status = F_EXEC_RUN;
 842 }
 843
 844 /* Run one execution_state; either to completion or to first result row */
 845 /* Returns true if we ran to completion */
 846 static bool
 847 postquel_getnext(execution_state *es, SQLFunctionCachePtr fcache)
 848 {
 849         bool            result;
 850
 851         if (es->qd->operation == CMD_UTILITY)
 852         {
 853                 ProcessUtility(es->qd->plannedstmt,
 854                                            fcache->src,
 855                                            PROCESS_UTILITY_QUERY,
 856                                            es->qd->params,
 857                                            es->qd->queryEnv,
 858                                            es->qd->dest,
 859                                            NULL);
 860                 result = true;                  /* never stops early */
 861         }
 862         else
 863         {
 864                 /* Run regular commands to completion unless lazyEval */
 865                 uint64          count = (es->lazyEval) ? 1 : 0;
 866
 867                 ExecutorRun(es->qd, ForwardScanDirection, count, !fcache->returnsSet || !es->lazyEval);
 868
 869                 /*
 870                  * If we requested run to completion OR there was no tuple returned,
 871                  * command must be complete.
 872                  */
 873                 result = (count == 0 || es->qd->estate->es_processed == 0);
 874         }
 875
 876         return result;
 877 }
 878
 879 /* Shut down execution of one execution_state node */
 880 static void
 881 postquel_end(execution_state *es)
 882 {
 883         /* mark status done to ensure we don't do ExecutorEnd twice */
 884         es->status = F_EXEC_DONE;
 885
 886         /* Utility commands don't need Executor. */
 887         if (es->qd->operation != CMD_UTILITY)
 888         {
 889                 ExecutorFinish(es->qd);
 890                 ExecutorEnd(es->qd);
 891         }
 892
 893         es->qd->dest->rDestroy(es->qd->dest);
 894
 895         FreeQueryDesc(es->qd);
 896         es->qd = NULL;
 897 }
 898
 899 /* Build ParamListInfo array representing current arguments */
 900 static void
 901 postquel_sub_params(SQLFunctionCachePtr fcache,
 902                                         FunctionCallInfo fcinfo)
 903 {
 904         int                     nargs = fcinfo->nargs;
 905
 906         if (nargs > 0)
 907         {
 908                 ParamListInfo paramLI;
 909                 int                     i;
 910
 911                 if (fcache->paramLI == NULL)
 912                 {
 913                         paramLI = (ParamListInfo)
 914                                 palloc(offsetof(ParamListInfoData, params) +
 915                                            nargs * sizeof(ParamExternData));
 916                         /* we have static list of params, so no hooks needed */
 917                         paramLI->paramFetch = NULL;
 918                         paramLI->paramFetchArg = NULL;
 919                         paramLI->paramCompile = NULL;
 920                         paramLI->paramCompileArg = NULL;
 921                         paramLI->parserSetup = NULL;
 922                         paramLI->parserSetupArg = NULL;
 923                         paramLI->numParams = nargs;
 924                         fcache->paramLI = paramLI;
 925                 }
 926                 else
 927                 {
 928                         paramLI = fcache->paramLI;
 929                         Assert(paramLI->numParams == nargs);
 930                 }
 931
 932                 for (i = 0; i < nargs; i++)
 933                 {
 934                         ParamExternData *prm = &paramLI->params[i];
 935
 936                         prm->value = fcinfo->arg[i];
 937                         prm->isnull = fcinfo->argnull[i];
 938                         prm->pflags = 0;
 939                         prm->ptype = fcache->pinfo->argtypes[i];
 940                 }
 941         }
 942         else
 943                 fcache->paramLI = NULL;
 944 }
 945
 946 /*
 947  * Extract the SQL function's value from a single result row.  This is used
 948  * both for scalar (non-set) functions and for each row of a lazy-eval set
 949  * result.
 950  */
 951 static Datum
 952 postquel_get_single_result(TupleTableSlot *slot,
 953                                                    FunctionCallInfo fcinfo,
 954                                                    SQLFunctionCachePtr fcache,
 955                                                    MemoryContext resultcontext)
 956 {
 957         Datum           value;
 958         MemoryContext oldcontext;
 959
 960         /*
 961          * Set up to return the function value.  For pass-by-reference datatypes,
 962          * be sure to allocate the result in resultcontext, not the current memory
 963          * context (which has query lifespan).  We can't leave the data in the
 964          * TupleTableSlot because we intend to clear the slot before returning.
 965          */
 966         oldcontext = MemoryContextSwitchTo(resultcontext);
 967
 968         if (fcache->returnsTuple)
 969         {
 970                 /* We must return the whole tuple as a Datum. */
 971                 fcinfo->isnull = false;
 972                 value = ExecFetchSlotTupleDatum(slot);
 973         }
 974         else
 975         {
 976                 /*
 977                  * Returning a scalar, which we have to extract from the first column
 978                  * of the SELECT result, and then copy into result context if needed.
 979                  */
 980                 value = slot_getattr(slot, 1, &(fcinfo->isnull));
 981
 982                 if (!fcinfo->isnull)
 983                         value = datumCopy(value, fcache->typbyval, fcache->typlen);
 984         }
 985
 986         MemoryContextSwitchTo(oldcontext);
 987
 988         return value;
 989 }
 990
 991 /*
 992  * fmgr_sql: function call manager for SQL functions
 993  */
 994 Datum
 995 fmgr_sql(PG_FUNCTION_ARGS)
 996 {
 997         SQLFunctionCachePtr fcache;
 998         ErrorContextCallback sqlerrcontext;
 999         MemoryContext oldcontext;
1000         bool            randomAccess;
1001         bool            lazyEvalOK;
1002         bool            is_first;
1003         bool            pushed_snapshot;
1004         execution_state *es;
1005         TupleTableSlot *slot;
1006         Datum           result;
1007         List       *eslist;
1008         ListCell   *eslc;
1009
1010         /*
1011          * Setup error traceback support for ereport()
1012          */
1013         sqlerrcontext.callback = sql_exec_error_callback;
1014         sqlerrcontext.arg = fcinfo->flinfo;
1015         sqlerrcontext.previous = error_context_stack;
1016         error_context_stack = &sqlerrcontext;
1017
1018         /* Check call context */
1019         if (fcinfo->flinfo->fn_retset)
1020         {
1021                 ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
1022
1023                 /*
1024                  * For simplicity, we require callers to support both set eval modes.
1025                  * There are cases where we must use one or must use the other, and
1026                  * it's not really worthwhile to postpone the check till we know. But
1027                  * note we do not require caller to provide an expectedDesc.
1028                  */
1029                 if (!rsi || !IsA(rsi, ReturnSetInfo) ||
1030                         (rsi->allowedModes & SFRM_ValuePerCall) == 0 ||
1031                         (rsi->allowedModes & SFRM_Materialize) == 0)
1032                         ereport(ERROR,
1033                                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1034                                          errmsg("set-valued function called in context that cannot accept a set")));
1035                 randomAccess = rsi->allowedModes & SFRM_Materialize_Random;
1036                 lazyEvalOK = !(rsi->allowedModes & SFRM_Materialize_Preferred);
1037         }
1038         else
1039         {
1040                 randomAccess = false;
1041                 lazyEvalOK = true;
1042         }
1043
1044         /*
1045          * Initialize fcache (build plans) if first time through; or re-initialize
1046          * if the cache is stale.
1047          */
1048         fcache = (SQLFunctionCachePtr) fcinfo->flinfo->fn_extra;
1049
1050         if (fcache != NULL)
1051         {
1052                 if (fcache->lxid != MyProc->lxid ||
1053                         !SubTransactionIsActive(fcache->subxid))
1054                 {
1055                         /* It's stale; unlink and delete */
1056                         fcinfo->flinfo->fn_extra = NULL;
1057                         MemoryContextDelete(fcache->fcontext);
1058                         fcache = NULL;
1059                 }
1060         }
1061
1062         if (fcache == NULL)
1063         {
1064                 init_sql_fcache(fcinfo->flinfo, PG_GET_COLLATION(), lazyEvalOK);
1065                 fcache = (SQLFunctionCachePtr) fcinfo->flinfo->fn_extra;
1066         }
1067
1068         /*
1069          * Switch to context in which the fcache lives.  This ensures that our
1070          * tuplestore etc will have sufficient lifetime.  The sub-executor is
1071          * responsible for deleting per-tuple information.  (XXX in the case of a
1072          * long-lived FmgrInfo, this policy represents more memory leakage, but
1073          * it's not entirely clear where to keep stuff instead.)
1074          */
1075         oldcontext = MemoryContextSwitchTo(fcache->fcontext);
1076
1077         /*
1078          * Find first unfinished query in function, and note whether it's the
1079          * first query.
1080          */
1081         eslist = fcache->func_state;
1082         es = NULL;
1083         is_first = true;
1084         foreach(eslc, eslist)
1085         {
1086                 es = (execution_state *) lfirst(eslc);
1087
1088                 while (es && es->status == F_EXEC_DONE)
1089                 {
1090                         is_first = false;
1091                         es = es->next;
1092                 }
1093
1094                 if (es)
1095                         break;
1096         }
1097
1098         /*
1099          * Convert params to appropriate format if starting a fresh execution. (If
1100          * continuing execution, we can re-use prior params.)
1101          */
1102         if (is_first && es && es->status == F_EXEC_START)
1103                 postquel_sub_params(fcache, fcinfo);
1104
1105         /*
1106          * Build tuplestore to hold results, if we don't have one already. Note
1107          * it's in the query-lifespan context.
1108          */
1109         if (!fcache->tstore)
1110                 fcache->tstore = tuplestore_begin_heap(randomAccess, false, work_mem);
1111
1112         /*
1113          * Execute each command in the function one after another until we either
1114          * run out of commands or get a result row from a lazily-evaluated SELECT.
1115          *
1116          * Notes about snapshot management:
1117          *
1118          * In a read-only function, we just use the surrounding query's snapshot.
1119          *
1120          * In a non-read-only function, we rely on the fact that we'll never
1121          * suspend execution between queries of the function: the only reason to
1122          * suspend execution before completion is if we are returning a row from a
1123          * lazily-evaluated SELECT.  So, when first entering this loop, we'll
1124          * either start a new query (and push a fresh snapshot) or re-establish
1125          * the active snapshot from the existing query descriptor.  If we need to
1126          * start a new query in a subsequent execution of the loop, either we need
1127          * a fresh snapshot (and pushed_snapshot is false) or the existing
1128          * snapshot is on the active stack and we can just bump its command ID.
1129          */
1130         pushed_snapshot = false;
1131         while (es)
1132         {
1133                 bool            completed;
1134
1135                 if (es->status == F_EXEC_START)
1136                 {
1137                         /*
1138                          * If not read-only, be sure to advance the command counter for
1139                          * each command, so that all work to date in this transaction is
1140                          * visible.  Take a new snapshot if we don't have one yet,
1141                          * otherwise just bump the command ID in the existing snapshot.
1142                          */
1143                         if (!fcache->readonly_func)
1144                         {
1145                                 CommandCounterIncrement();
1146                                 if (!pushed_snapshot)
1147                                 {
1148                                         PushActiveSnapshot(GetTransactionSnapshot());
1149                                         pushed_snapshot = true;
1150                                 }
1151                                 else
1152                                         UpdateActiveSnapshotCommandId();
1153                         }
1154
1155                         postquel_start(es, fcache);
1156                 }
1157                 else if (!fcache->readonly_func && !pushed_snapshot)
1158                 {
1159                         /* Re-establish active snapshot when re-entering function */
1160                         PushActiveSnapshot(es->qd->snapshot);
1161                         pushed_snapshot = true;
1162                 }
1163
1164                 completed = postquel_getnext(es, fcache);
1165
1166                 /*
1167                  * If we ran the command to completion, we can shut it down now. Any
1168                  * row(s) we need to return are safely stashed in the tuplestore, and
1169                  * we want to be sure that, for example, AFTER triggers get fired
1170                  * before we return anything.  Also, if the function doesn't return
1171                  * set, we can shut it down anyway because it must be a SELECT and we
1172                  * don't care about fetching any more result rows.
1173                  */
1174                 if (completed || !fcache->returnsSet)
1175                         postquel_end(es);
1176
1177                 /*
1178                  * Break from loop if we didn't shut down (implying we got a
1179                  * lazily-evaluated row).  Otherwise we'll press on till the whole
1180                  * function is done, relying on the tuplestore to keep hold of the
1181                  * data to eventually be returned.  This is necessary since an
1182                  * INSERT/UPDATE/DELETE RETURNING that sets the result might be
1183                  * followed by additional rule-inserted commands, and we want to
1184                  * finish doing all those commands before we return anything.
1185                  */
1186                 if (es->status != F_EXEC_DONE)
1187                         break;
1188
1189                 /*
1190                  * Advance to next execution_state, which might be in the next list.
1191                  */
1192                 es = es->next;
1193                 while (!es)
1194                 {
1195                         eslc = lnext(eslc);
1196                         if (!eslc)
1197                                 break;                  /* end of function */
1198
1199                         es = (execution_state *) lfirst(eslc);
1200
1201                         /*
1202                          * Flush the current snapshot so that we will take a new one for
1203                          * the new query list.  This ensures that new snaps are taken at
1204                          * original-query boundaries, matching the behavior of interactive
1205                          * execution.
1206                          */
1207                         if (pushed_snapshot)
1208                         {
1209                                 PopActiveSnapshot();
1210                                 pushed_snapshot = false;
1211                         }
1212                 }
1213         }
1214
1215         /*
1216          * The tuplestore now contains whatever row(s) we are supposed to return.
1217          */
1218         if (fcache->returnsSet)
1219         {
1220                 ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
1221
1222                 if (es)
1223                 {
1224                         /*
1225                          * If we stopped short of being done, we must have a lazy-eval
1226                          * row.
1227                          */
1228                         Assert(es->lazyEval);
1229                         /* Re-use the junkfilter's output slot to fetch back the tuple */
1230                         Assert(fcache->junkFilter);
1231                         slot = fcache->junkFilter->jf_resultSlot;
1232                         if (!tuplestore_gettupleslot(fcache->tstore, true, false, slot))
1233                                 elog(ERROR, "failed to fetch lazy-eval tuple");
1234                         /* Extract the result as a datum, and copy out from the slot */
1235                         result = postquel_get_single_result(slot, fcinfo,
1236                                                                                                 fcache, oldcontext);
1237                         /* Clear the tuplestore, but keep it for next time */
1238                         /* NB: this might delete the slot's content, but we don't care */
1239                         tuplestore_clear(fcache->tstore);
1240
1241                         /*
1242                          * Let caller know we're not finished.
1243                          */
1244                         rsi->isDone = ExprMultipleResult;
1245
1246                         /*
1247                          * Ensure we will get shut down cleanly if the exprcontext is not
1248                          * run to completion.
1249                          */
1250                         if (!fcache->shutdown_reg)
1251                         {
1252                                 RegisterExprContextCallback(rsi->econtext,
1253                                                                                         ShutdownSQLFunction,
1254                                                                                         PointerGetDatum(fcache));
1255                                 fcache->shutdown_reg = true;
1256                         }
1257                 }
1258                 else if (fcache->lazyEval)
1259                 {
1260                         /*
1261                          * We are done with a lazy evaluation.  Clean up.
1262                          */
1263                         tuplestore_clear(fcache->tstore);
1264
1265                         /*
1266                          * Let caller know we're finished.
1267                          */
1268                         rsi->isDone = ExprEndResult;
1269
1270                         fcinfo->isnull = true;
1271                         result = (Datum) 0;
1272
1273                         /* Deregister shutdown callback, if we made one */
1274                         if (fcache->shutdown_reg)
1275                         {
1276                                 UnregisterExprContextCallback(rsi->econtext,
1277                                                                                           ShutdownSQLFunction,
1278                                                                                           PointerGetDatum(fcache));
1279                                 fcache->shutdown_reg = false;
1280                         }
1281                 }
1282                 else
1283                 {
1284                         /*
1285                          * We are done with a non-lazy evaluation.  Return whatever is in
1286                          * the tuplestore.  (It is now caller's responsibility to free the
1287                          * tuplestore when done.)
1288                          */
1289                         rsi->returnMode = SFRM_Materialize;
1290                         rsi->setResult = fcache->tstore;
1291                         fcache->tstore = NULL;
1292                         /* must copy desc because execSRF.c will free it */
1293                         if (fcache->junkFilter)
1294                                 rsi->setDesc = CreateTupleDescCopy(fcache->junkFilter->jf_cleanTupType);
1295
1296                         fcinfo->isnull = true;
1297                         result = (Datum) 0;
1298
1299                         /* Deregister shutdown callback, if we made one */
1300                         if (fcache->shutdown_reg)
1301                         {
1302                                 UnregisterExprContextCallback(rsi->econtext,
1303                                                                                           ShutdownSQLFunction,
1304                                                                                           PointerGetDatum(fcache));
1305                                 fcache->shutdown_reg = false;
1306                         }
1307                 }
1308         }
1309         else
1310         {
1311                 /*
1312                  * Non-set function.  If we got a row, return it; else return NULL.
1313                  */
1314                 if (fcache->junkFilter)
1315                 {
1316                         /* Re-use the junkfilter's output slot to fetch back the tuple */
1317                         slot = fcache->junkFilter->jf_resultSlot;
1318                         if (tuplestore_gettupleslot(fcache->tstore, true, false, slot))
1319                                 result = postquel_get_single_result(slot, fcinfo,
1320                                                                                                         fcache, oldcontext);
1321                         else
1322                         {
1323                                 fcinfo->isnull = true;
1324                                 result = (Datum) 0;
1325                         }
1326                 }
1327                 else
1328                 {
1329                         /* Should only get here for VOID functions and procedures */
1330                         Assert(fcache->rettype == VOIDOID);
1331                         fcinfo->isnull = true;
1332                         result = (Datum) 0;
1333                 }
1334
1335                 /* Clear the tuplestore, but keep it for next time */
1336                 tuplestore_clear(fcache->tstore);
1337         }
1338
1339         /* Pop snapshot if we have pushed one */
1340         if (pushed_snapshot)
1341                 PopActiveSnapshot();
1342
1343         /*
1344          * If we've gone through every command in the function, we are done. Reset
1345          * the execution states to start over again on next call.
1346          */
1347         if (es == NULL)
1348         {
1349                 foreach(eslc, fcache->func_state)
1350                 {
1351                         es = (execution_state *) lfirst(eslc);
1352                         while (es)
1353                         {
1354                                 es->status = F_EXEC_START;
1355                                 es = es->next;
1356                         }
1357                 }
1358         }
1359
1360         error_context_stack = sqlerrcontext.previous;
1361
1362         MemoryContextSwitchTo(oldcontext);
1363
1364         return result;
1365 }
1366
1367
1368 /*
1369  * error context callback to let us supply a call-stack traceback
1370  */
1371 static void
1372 sql_exec_error_callback(void *arg)
1373 {
1374         FmgrInfo   *flinfo = (FmgrInfo *) arg;
1375         SQLFunctionCachePtr fcache = (SQLFunctionCachePtr) flinfo->fn_extra;
1376         int                     syntaxerrposition;
1377
1378         /*
1379          * We can do nothing useful if init_sql_fcache() didn't get as far as
1380          * saving the function name
1381          */
1382         if (fcache == NULL || fcache->fname == NULL)
1383                 return;
1384
1385         /*
1386          * If there is a syntax error position, convert to internal syntax error
1387          */
1388         syntaxerrposition = geterrposition();
1389         if (syntaxerrposition > 0 && fcache->src != NULL)
1390         {
1391                 errposition(0);
1392                 internalerrposition(syntaxerrposition);
1393                 internalerrquery(fcache->src);
1394         }
1395
1396         /*
1397          * Try to determine where in the function we failed.  If there is a query
1398          * with non-null QueryDesc, finger it.  (We check this rather than looking
1399          * for F_EXEC_RUN state, so that errors during ExecutorStart or
1400          * ExecutorEnd are blamed on the appropriate query; see postquel_start and
1401          * postquel_end.)
1402          */
1403         if (fcache->func_state)
1404         {
1405                 execution_state *es;
1406                 int                     query_num;
1407                 ListCell   *lc;
1408
1409                 es = NULL;
1410                 query_num = 1;
1411                 foreach(lc, fcache->func_state)
1412                 {
1413                         es = (execution_state *) lfirst(lc);
1414                         while (es)
1415                         {
1416                                 if (es->qd)
1417                                 {
1418                                         errcontext("SQL function \"%s\" statement %d",
1419                                                            fcache->fname, query_num);
1420                                         break;
1421                                 }
1422                                 es = es->next;
1423                         }
1424                         if (es)
1425                                 break;
1426                         query_num++;
1427                 }
1428                 if (es == NULL)
1429                 {
1430                         /*
1431                          * couldn't identify a running query; might be function entry,
1432                          * function exit, or between queries.
1433                          */
1434                         errcontext("SQL function \"%s\"", fcache->fname);
1435                 }
1436         }
1437         else
1438         {
1439                 /*
1440                  * Assume we failed during init_sql_fcache().  (It's possible that the
1441                  * function actually has an empty body, but in that case we may as
1442                  * well report all errors as being "during startup".)
1443                  */
1444                 errcontext("SQL function \"%s\" during startup", fcache->fname);
1445         }
1446 }
1447
1448
1449 /*
1450  * callback function in case a function-returning-set needs to be shut down
1451  * before it has been run to completion
1452  */
1453 static void
1454 ShutdownSQLFunction(Datum arg)
1455 {
1456         SQLFunctionCachePtr fcache = (SQLFunctionCachePtr) DatumGetPointer(arg);
1457         execution_state *es;
1458         ListCell   *lc;
1459
1460         foreach(lc, fcache->func_state)
1461         {
1462                 es = (execution_state *) lfirst(lc);
1463                 while (es)
1464                 {
1465                         /* Shut down anything still running */
1466                         if (es->status == F_EXEC_RUN)
1467                         {
1468                                 /* Re-establish active snapshot for any called functions */
1469                                 if (!fcache->readonly_func)
1470                                         PushActiveSnapshot(es->qd->snapshot);
1471
1472                                 postquel_end(es);
1473
1474                                 if (!fcache->readonly_func)
1475                                         PopActiveSnapshot();
1476                         }
1477
1478                         /* Reset states to START in case we're called again */
1479                         es->status = F_EXEC_START;
1480                         es = es->next;
1481                 }
1482         }
1483
1484         /* Release tuplestore if we have one */
1485         if (fcache->tstore)
1486                 tuplestore_end(fcache->tstore);
1487         fcache->tstore = NULL;
1488
1489         /* execUtils will deregister the callback... */
1490         fcache->shutdown_reg = false;
1491 }
1492
1493 /*
1494  * check_sql_fn_statements
1495  *
1496  * Check statements in an SQL function.  Error out if there is anything that
1497  * is not acceptable.
1498  */
1499 void
1500 check_sql_fn_statements(List *queryTreeList)
1501 {
1502         ListCell   *lc;
1503
1504         foreach(lc, queryTreeList)
1505         {
1506                 Query      *query = lfirst_node(Query, lc);
1507
1508                 /*
1509                  * Disallow procedures with output arguments.  The current
1510                  * implementation would just throw the output values away, unless the
1511                  * statement is the last one.  Per SQL standard, we should assign the
1512                  * output values by name.  By disallowing this here, we preserve an
1513                  * opportunity for future improvement.
1514                  */
1515                 if (query->commandType == CMD_UTILITY &&
1516                         IsA(query->utilityStmt, CallStmt))
1517                 {
1518                         CallStmt   *stmt = castNode(CallStmt, query->utilityStmt);
1519                         HeapTuple       tuple;
1520                         int                     numargs;
1521                         Oid                *argtypes;
1522                         char      **argnames;
1523                         char       *argmodes;
1524                         int                     i;
1525
1526                         tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(stmt->funcexpr->funcid));
1527                         if (!HeapTupleIsValid(tuple))
1528                                 elog(ERROR, "cache lookup failed for function %u", stmt->funcexpr->funcid);
1529                         numargs = get_func_arg_info(tuple, &argtypes, &argnames, &argmodes);
1530                         ReleaseSysCache(tuple);
1531
1532                         for (i = 0; i < numargs; i++)
1533                         {
1534                                 if (argmodes && (argmodes[i] == PROARGMODE_INOUT || argmodes[i] == PROARGMODE_OUT))
1535                                         ereport(ERROR,
1536                                                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1537                                                          errmsg("calling procedures with output arguments is not supported in SQL functions")));
1538                         }
1539                 }
1540         }
1541 }
1542
1543 /*
1544  * check_sql_fn_retval() -- check return value of a list of sql parse trees.
1545  *
1546  * The return value of a sql function is the value returned by the last
1547  * canSetTag query in the function.  We do some ad-hoc type checking here
1548  * to be sure that the user is returning the type he claims.  There are
1549  * also a couple of strange-looking features to assist callers in dealing
1550  * with allowed special cases, such as binary-compatible result types.
1551  *
1552  * For a polymorphic function the passed rettype must be the actual resolved
1553  * output type of the function; we should never see a polymorphic pseudotype
1554  * such as ANYELEMENT as rettype.  (This means we can't check the type during
1555  * function definition of a polymorphic function.)
1556  *
1557  * This function returns true if the sql function returns the entire tuple
1558  * result of its final statement, or false if it returns just the first column
1559  * result of that statement.  It throws an error if the final statement doesn't
1560  * return the right type at all.
1561  *
1562  * Note that because we allow "SELECT rowtype_expression", the result can be
1563  * false even when the declared function return type is a rowtype.
1564  *
1565  * If modifyTargetList isn't NULL, the function will modify the final
1566  * statement's targetlist in two cases:
1567  * (1) if the tlist returns values that are binary-coercible to the expected
1568  * type rather than being exactly the expected type.  RelabelType nodes will
1569  * be inserted to make the result types match exactly.
1570  * (2) if there are dropped columns in the declared result rowtype.  NULL
1571  * output columns will be inserted in the tlist to match them.
1572  * (Obviously the caller must pass a parsetree that is okay to modify when
1573  * using this flag.)  Note that this flag does not affect whether the tlist is
1574  * considered to be a legal match to the result type, only how we react to
1575  * allowed not-exact-match cases.  *modifyTargetList will be set true iff
1576  * we had to make any "dangerous" changes that could modify the semantics of
1577  * the statement.  If it is set true, the caller should not use the modified
1578  * statement, but for simplicity we apply the changes anyway.
1579  *
1580  * If junkFilter isn't NULL, then *junkFilter is set to a JunkFilter defined
1581  * to convert the function's tuple result to the correct output tuple type.
1582  * Exception: if the function is defined to return VOID then *junkFilter is
1583  * set to NULL.
1584  */
1585 bool
1586 check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
1587                                         bool *modifyTargetList,
1588                                         JunkFilter **junkFilter)
1589 {
1590         Query      *parse;
1591         List      **tlist_ptr;
1592         List       *tlist;
1593         int                     tlistlen;
1594         char            fn_typtype;
1595         Oid                     restype;
1596         ListCell   *lc;
1597
1598         AssertArg(!IsPolymorphicType(rettype));
1599
1600         if (modifyTargetList)
1601                 *modifyTargetList = false;      /* initialize for no change */
1602         if (junkFilter)
1603                 *junkFilter = NULL;             /* initialize in case of VOID result */
1604
1605         /*
1606          * If it's declared to return VOID, we don't care what's in the function.
1607          * (This takes care of the procedure case, as well.)
1608          */
1609         if (rettype == VOIDOID)
1610                 return false;
1611
1612         /*
1613          * Find the last canSetTag query in the list.  This isn't necessarily the
1614          * last parsetree, because rule rewriting can insert queries after what
1615          * the user wrote.
1616          */
1617         parse = NULL;
1618         foreach(lc, queryTreeList)
1619         {
1620                 Query      *q = lfirst_node(Query, lc);
1621
1622                 if (q->canSetTag)
1623                         parse = q;
1624         }
1625
1626         /*
1627          * If it's a plain SELECT, it returns whatever the targetlist says.
1628          * Otherwise, if it's INSERT/UPDATE/DELETE with RETURNING, it returns
1629          * that. Otherwise, the function return type must be VOID.
1630          *
1631          * Note: eventually replace this test with QueryReturnsTuples?  We'd need
1632          * a more general method of determining the output type, though.  Also, it
1633          * seems too dangerous to consider FETCH or EXECUTE as returning a
1634          * determinable rowtype, since they depend on relatively short-lived
1635          * entities.
1636          */
1637         if (parse &&
1638                 parse->commandType == CMD_SELECT)
1639         {
1640                 tlist_ptr = &parse->targetList;
1641                 tlist = parse->targetList;
1642         }
1643         else if (parse &&
1644                          (parse->commandType == CMD_INSERT ||
1645                           parse->commandType == CMD_UPDATE ||
1646                           parse->commandType == CMD_DELETE) &&
1647                          parse->returningList)
1648         {
1649                 tlist_ptr = &parse->returningList;
1650                 tlist = parse->returningList;
1651         }
1652         else
1653         {
1654                 /* Empty function body, or last statement is a utility command */
1655                 ereport(ERROR,
1656                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1657                                  errmsg("return type mismatch in function declared to return %s",
1658                                                 format_type_be(rettype)),
1659                                  errdetail("Function's final statement must be SELECT or INSERT/UPDATE/DELETE RETURNING.")));
1660                 return false;                   /* keep compiler quiet */
1661         }
1662
1663         /*
1664          * OK, check that the targetlist returns something matching the declared
1665          * type.
1666          */
1667
1668         /*
1669          * Count the non-junk entries in the result targetlist.
1670          */
1671         tlistlen = ExecCleanTargetListLength(tlist);
1672
1673         fn_typtype = get_typtype(rettype);
1674
1675         if (fn_typtype == TYPTYPE_BASE ||
1676                 fn_typtype == TYPTYPE_DOMAIN ||
1677                 fn_typtype == TYPTYPE_ENUM ||
1678                 fn_typtype == TYPTYPE_RANGE)
1679         {
1680                 /*
1681                  * For scalar-type returns, the target list must have exactly one
1682                  * non-junk entry, and its type must agree with what the user
1683                  * declared; except we allow binary-compatible types too.
1684                  */
1685                 TargetEntry *tle;
1686
1687                 if (tlistlen != 1)
1688                         ereport(ERROR,
1689                                         (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1690                                          errmsg("return type mismatch in function declared to return %s",
1691                                                         format_type_be(rettype)),
1692                                          errdetail("Final statement must return exactly one column.")));
1693
1694                 /* We assume here that non-junk TLEs must come first in tlists */
1695                 tle = (TargetEntry *) linitial(tlist);
1696                 Assert(!tle->resjunk);
1697
1698                 restype = exprType((Node *) tle->expr);
1699                 if (!IsBinaryCoercible(restype, rettype))
1700                         ereport(ERROR,
1701                                         (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1702                                          errmsg("return type mismatch in function declared to return %s",
1703                                                         format_type_be(rettype)),
1704                                          errdetail("Actual return type is %s.",
1705                                                            format_type_be(restype))));
1706                 if (modifyTargetList && restype != rettype)
1707                 {
1708                         tle->expr = (Expr *) makeRelabelType(tle->expr,
1709                                                                                                  rettype,
1710                                                                                                  -1,
1711                                                                                                  get_typcollation(rettype),
1712                                                                                                  COERCE_IMPLICIT_CAST);
1713                         /* Relabel is dangerous if TLE is a sort/group or setop column */
1714                         if (tle->ressortgroupref != 0 || parse->setOperations)
1715                                 *modifyTargetList = true;
1716                 }
1717
1718                 /* Set up junk filter if needed */
1719                 if (junkFilter)
1720                         *junkFilter = ExecInitJunkFilter(tlist, false, NULL);
1721         }
1722         else if (fn_typtype == TYPTYPE_COMPOSITE || rettype == RECORDOID)
1723         {
1724                 /*
1725                  * Returns a rowtype.
1726                  *
1727                  * Note that we will not consider a domain over composite to be a
1728                  * "rowtype" return type; it goes through the scalar case above.  This
1729                  * is because SQL functions don't provide any implicit casting to the
1730                  * result type, so there is no way to produce a domain-over-composite
1731                  * result except by computing it as an explicit single-column result.
1732                  */
1733                 TupleDesc       tupdesc;
1734                 int                     tupnatts;       /* physical number of columns in tuple */
1735                 int                     tuplogcols; /* # of nondeleted columns in tuple */
1736                 int                     colindex;       /* physical column index */
1737                 List       *newtlist;   /* new non-junk tlist entries */
1738                 List       *junkattrs;  /* new junk tlist entries */
1739
1740                 /*
1741                  * If the target list is of length 1, and the type of the varnode in
1742                  * the target list matches the declared return type, this is okay.
1743                  * This can happen, for example, where the body of the function is
1744                  * 'SELECT func2()', where func2 has the same composite return type as
1745                  * the function that's calling it.
1746                  *
1747                  * XXX Note that if rettype is RECORD, the IsBinaryCoercible check
1748                  * will succeed for any composite restype.  For the moment we rely on
1749                  * runtime type checking to catch any discrepancy, but it'd be nice to
1750                  * do better at parse time.
1751                  */
1752                 if (tlistlen == 1)
1753                 {
1754                         TargetEntry *tle = (TargetEntry *) linitial(tlist);
1755
1756                         Assert(!tle->resjunk);
1757                         restype = exprType((Node *) tle->expr);
1758                         if (IsBinaryCoercible(restype, rettype))
1759                         {
1760                                 if (modifyTargetList && restype != rettype)
1761                                 {
1762                                         tle->expr = (Expr *) makeRelabelType(tle->expr,
1763                                                                                                                  rettype,
1764                                                                                                                  -1,
1765                                                                                                                  get_typcollation(rettype),
1766                                                                                                                  COERCE_IMPLICIT_CAST);
1767                                         /* Relabel is dangerous if sort/group or setop column */
1768                                         if (tle->ressortgroupref != 0 || parse->setOperations)
1769                                                 *modifyTargetList = true;
1770                                 }
1771                                 /* Set up junk filter if needed */
1772                                 if (junkFilter)
1773                                         *junkFilter = ExecInitJunkFilter(tlist, false, NULL);
1774                                 return false;   /* NOT returning whole tuple */
1775                         }
1776                 }
1777
1778                 /*
1779                  * Is the rowtype fixed, or determined only at runtime?  (Note we
1780                  * cannot see TYPEFUNC_COMPOSITE_DOMAIN here.)
1781                  */
1782                 if (get_func_result_type(func_id, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
1783                 {
1784                         /*
1785                          * Assume we are returning the whole tuple. Crosschecking against
1786                          * what the caller expects will happen at runtime.
1787                          */
1788                         if (junkFilter)
1789                                 *junkFilter = ExecInitJunkFilter(tlist, false, NULL);
1790                         return true;
1791                 }
1792                 Assert(tupdesc);
1793
1794                 /*
1795                  * Verify that the targetlist matches the return tuple type. We scan
1796                  * the non-deleted attributes to ensure that they match the datatypes
1797                  * of the non-resjunk columns.  For deleted attributes, insert NULL
1798                  * result columns if the caller asked for that.
1799                  */
1800                 tupnatts = tupdesc->natts;
1801                 tuplogcols = 0;                 /* we'll count nondeleted cols as we go */
1802                 colindex = 0;
1803                 newtlist = NIL;                 /* these are only used if modifyTargetList */
1804                 junkattrs = NIL;
1805
1806                 foreach(lc, tlist)
1807                 {
1808                         TargetEntry *tle = (TargetEntry *) lfirst(lc);
1809                         Form_pg_attribute attr;
1810                         Oid                     tletype;
1811                         Oid                     atttype;
1812
1813                         if (tle->resjunk)
1814                         {
1815                                 if (modifyTargetList)
1816                                         junkattrs = lappend(junkattrs, tle);
1817                                 continue;
1818                         }
1819
1820                         do
1821                         {
1822                                 colindex++;
1823                                 if (colindex > tupnatts)
1824                                         ereport(ERROR,
1825                                                         (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1826                                                          errmsg("return type mismatch in function declared to return %s",
1827                                                                         format_type_be(rettype)),
1828                                                          errdetail("Final statement returns too many columns.")));
1829                                 attr = TupleDescAttr(tupdesc, colindex - 1);
1830                                 if (attr->attisdropped && modifyTargetList)
1831                                 {
1832                                         Expr       *null_expr;
1833
1834                                         /* The type of the null we insert isn't important */
1835                                         null_expr = (Expr *) makeConst(INT4OID,
1836                                                                                                    -1,
1837                                                                                                    InvalidOid,
1838                                                                                                    sizeof(int32),
1839                                                                                                    (Datum) 0,
1840                                                                                                    true,        /* isnull */
1841                                                                                                    true /* byval */ );
1842                                         newtlist = lappend(newtlist,
1843                                                                            makeTargetEntry(null_expr,
1844                                                                                                            colindex,
1845                                                                                                            NULL,
1846                                                                                                            false));
1847                                         /* NULL insertion is dangerous in a setop */
1848                                         if (parse->setOperations)
1849                                                 *modifyTargetList = true;
1850                                 }
1851                         } while (attr->attisdropped);
1852                         tuplogcols++;
1853
1854                         tletype = exprType((Node *) tle->expr);
1855                         atttype = attr->atttypid;
1856                         if (!IsBinaryCoercible(tletype, atttype))
1857                                 ereport(ERROR,
1858                                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1859                                                  errmsg("return type mismatch in function declared to return %s",
1860                                                                 format_type_be(rettype)),
1861                                                  errdetail("Final statement returns %s instead of %s at column %d.",
1862                                                                    format_type_be(tletype),
1863                                                                    format_type_be(atttype),
1864                                                                    tuplogcols)));
1865                         if (modifyTargetList)
1866                         {
1867                                 if (tletype != atttype)
1868                                 {
1869                                         tle->expr = (Expr *) makeRelabelType(tle->expr,
1870                                                                                                                  atttype,
1871                                                                                                                  -1,
1872                                                                                                                  get_typcollation(atttype),
1873                                                                                                                  COERCE_IMPLICIT_CAST);
1874                                         /* Relabel is dangerous if sort/group or setop column */
1875                                         if (tle->ressortgroupref != 0 || parse->setOperations)
1876                                                 *modifyTargetList = true;
1877                                 }
1878                                 tle->resno = colindex;
1879                                 newtlist = lappend(newtlist, tle);
1880                         }
1881                 }
1882
1883                 /* remaining columns in tupdesc had better all be dropped */
1884                 for (colindex++; colindex <= tupnatts; colindex++)
1885                 {
1886                         if (!TupleDescAttr(tupdesc, colindex - 1)->attisdropped)
1887                                 ereport(ERROR,
1888                                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1889                                                  errmsg("return type mismatch in function declared to return %s",
1890                                                                 format_type_be(rettype)),
1891                                                  errdetail("Final statement returns too few columns.")));
1892                         if (modifyTargetList)
1893                         {
1894                                 Expr       *null_expr;
1895
1896                                 /* The type of the null we insert isn't important */
1897                                 null_expr = (Expr *) makeConst(INT4OID,
1898                                                                                            -1,
1899                                                                                            InvalidOid,
1900                                                                                            sizeof(int32),
1901                                                                                            (Datum) 0,
1902                                                                                            true,        /* isnull */
1903                                                                                            true /* byval */ );
1904                                 newtlist = lappend(newtlist,
1905                                                                    makeTargetEntry(null_expr,
1906                                                                                                    colindex,
1907                                                                                                    NULL,
1908                                                                                                    false));
1909                                 /* NULL insertion is dangerous in a setop */
1910                                 if (parse->setOperations)
1911                                         *modifyTargetList = true;
1912                         }
1913                 }
1914
1915                 if (modifyTargetList)
1916                 {
1917                         /* ensure resjunk columns are numbered correctly */
1918                         foreach(lc, junkattrs)
1919                         {
1920                                 TargetEntry *tle = (TargetEntry *) lfirst(lc);
1921
1922                                 tle->resno = colindex++;
1923                         }
1924                         /* replace the tlist with the modified one */
1925                         *tlist_ptr = list_concat(newtlist, junkattrs);
1926                 }
1927
1928                 /* Set up junk filter if needed */
1929                 if (junkFilter)
1930                         *junkFilter = ExecInitJunkFilterConversion(tlist,
1931                                                                                                            CreateTupleDescCopy(tupdesc),
1932                                                                                                            NULL);
1933
1934                 /* Report that we are returning entire tuple result */
1935                 return true;
1936         }
1937         else
1938                 ereport(ERROR,
1939                                 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1940                                  errmsg("return type %s is not supported for SQL functions",
1941                                                 format_type_be(rettype))));
1942
1943         return false;
1944 }
1945
1946
1947 /*
1948  * CreateSQLFunctionDestReceiver -- create a suitable DestReceiver object
1949  */
1950 DestReceiver *
1951 CreateSQLFunctionDestReceiver(void)
1952 {
1953         DR_sqlfunction *self = (DR_sqlfunction *) palloc0(sizeof(DR_sqlfunction));
1954
1955         self->pub.receiveSlot = sqlfunction_receive;
1956         self->pub.rStartup = sqlfunction_startup;
1957         self->pub.rShutdown = sqlfunction_shutdown;
1958         self->pub.rDestroy = sqlfunction_destroy;
1959         self->pub.mydest = DestSQLFunction;
1960
1961         /* private fields will be set by postquel_start */
1962
1963         return (DestReceiver *) self;
1964 }
1965
1966 /*
1967  * sqlfunction_startup --- executor startup
1968  */
1969 static void
1970 sqlfunction_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
1971 {
1972         /* no-op */
1973 }
1974
1975 /*
1976  * sqlfunction_receive --- receive one tuple
1977  */
1978 static bool
1979 sqlfunction_receive(TupleTableSlot *slot, DestReceiver *self)
1980 {
1981         DR_sqlfunction *myState = (DR_sqlfunction *) self;
1982
1983         /* Filter tuple as needed */
1984         slot = ExecFilterJunk(myState->filter, slot);
1985
1986         /* Store the filtered tuple into the tuplestore */
1987         tuplestore_puttupleslot(myState->tstore, slot);
1988
1989         return true;
1990 }
1991
1992 /*
1993  * sqlfunction_shutdown --- executor end
1994  */
1995 static void
1996 sqlfunction_shutdown(DestReceiver *self)
1997 {
1998         /* no-op */
1999 }
2000
2001 /*
2002  * sqlfunction_destroy --- release DestReceiver object
2003  */
2004 static void
2005 sqlfunction_destroy(DestReceiver *self)
2006 {
2007         pfree(self);
2008 }