1 /*-------------------------------------------------------------------------
4 * Execution of SQL-language functions
6 * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
11 * src/backend/executor/functions.c
13 *-------------------------------------------------------------------------
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"
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"
39 * Specialized DestReceiver for collecting query output in a SQL function
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 */
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.
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.)
60 F_EXEC_START, F_EXEC_RUN, F_EXEC_DONE
63 typedef struct execution_state
65 struct execution_state *next;
67 bool setsResult; /* true if this query produces func's result */
68 bool lazyEval; /* true if should fetch one row at a time */
69 Node *stmt; /* PlannedStmt or utility statement */
70 QueryDesc *qd; /* null unless status == RUN */
75 * An SQLFunctionCache record is built during the first call,
76 * and linked to from the fn_extra field of the FmgrInfo struct.
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.
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.
93 char *fname; /* function name (for error msgs) */
94 char *src; /* function body text (for error msgs) */
96 SQLFunctionParseInfoPtr pinfo; /* data for parser callback hooks */
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 */
107 ParamListInfo paramLI; /* Param list representing current args */
109 Tuplestorestate *tstore; /* where we accumulate result tuples */
111 JunkFilter *junkFilter; /* will be NULL if function returns VOID */
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.
121 MemoryContext fcontext; /* memory context holding this struct and all
124 LocalTransactionId lxid; /* lxid in which cache was made */
125 SubTransactionId subxid; /* subxid in which cache was made */
128 typedef SQLFunctionCache *SQLFunctionCachePtr;
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.
135 typedef struct SQLFunctionParseInfo
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;
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,
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 void sqlfunction_receive(TupleTableSlot *slot, DestReceiver *self);
171 static void sqlfunction_shutdown(DestReceiver *self);
172 static void sqlfunction_destroy(DestReceiver *self);
176 * Prepare the SQLFunctionParseInfo struct for parsing a SQL function body
178 * This includes resolving actual types of polymorphic arguments.
180 * call_expr can be passed as NULL, but then we will fail if there are any
181 * polymorphic arguments.
183 SQLFunctionParseInfoPtr
184 prepare_sql_fn_parse_info(HeapTuple procedureTuple,
188 SQLFunctionParseInfoPtr pinfo;
189 Form_pg_proc procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple);
192 pinfo = (SQLFunctionParseInfoPtr) palloc0(sizeof(SQLFunctionParseInfo));
194 /* Function's name (only) can be used to qualify argument names */
195 pinfo->fname = pstrdup(NameStr(procedureStruct->proname));
197 /* Save the function's input collation */
198 pinfo->collation = inputCollation;
201 * Copy input argument types from the pg_proc entry, then resolve any
204 pinfo->nargs = nargs = procedureStruct->pronargs;
210 argOidVect = (Oid *) palloc(nargs * sizeof(Oid));
212 procedureStruct->proargtypes.values,
213 nargs * sizeof(Oid));
215 for (argnum = 0; argnum < nargs; argnum++)
217 Oid argtype = argOidVect[argnum];
219 if (IsPolymorphicType(argtype))
221 argtype = get_call_expr_argtype(call_expr, argnum);
222 if (argtype == InvalidOid)
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;
231 pinfo->argtypes = argOidVect;
235 * Collect names of arguments, too, if any
244 proargnames = SysCacheGetAttr(PROCNAMEARGSNSP, procedureTuple,
245 Anum_pg_proc_proargnames,
248 proargnames = PointerGetDatum(NULL); /* just to be sure */
250 proargmodes = SysCacheGetAttr(PROCNAMEARGSNSP, procedureTuple,
251 Anum_pg_proc_proargmodes,
254 proargmodes = PointerGetDatum(NULL); /* just to be sure */
256 n_arg_names = get_func_input_arg_names(proargnames, proargmodes,
259 /* Paranoia: ignore the result if too few array entries */
260 if (n_arg_names < nargs)
261 pinfo->argnames = NULL;
264 pinfo->argnames = NULL;
270 * Parser setup hook for parsing a SQL function body.
273 sql_fn_parser_setup(struct ParseState *pstate, SQLFunctionParseInfoPtr pinfo)
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;
283 * sql_fn_post_column_ref parser callback for ColumnRefs
286 sql_fn_post_column_ref(ParseState *pstate, ColumnRef *cref, Node *var)
288 SQLFunctionParseInfoPtr pinfo = (SQLFunctionParseInfoPtr) pstate->p_ref_hook_state;
291 Node *subfield = NULL;
293 const char *name2 = NULL;
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.
305 * The allowed syntaxes are:
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,
313 * A.* Whole-row reference to composite parameter A.
314 * A.B.* Same, with A = function name, B = parameter name
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.
320 nnames = list_length(cref->fields);
325 if (IsA(llast(cref->fields), A_Star))
328 field1 = (Node *) linitial(cref->fields);
329 Assert(IsA(field1, String));
330 name1 = strVal(field1);
333 subfield = (Node *) lsecond(cref->fields);
334 Assert(IsA(subfield, String));
335 name2 = strVal(subfield);
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.
345 if (strcmp(name1, pinfo->fname) != 0)
348 param = sql_fn_resolve_param_name(pinfo, name2, cref->location);
350 subfield = (Node *) lthird(cref->fields);
351 Assert(IsA(subfield, String));
353 else if (nnames == 2 && strcmp(name1, pinfo->fname) == 0)
356 * Two-part name with first part matching function name: first see if
357 * second part matches any parameter name.
359 param = sql_fn_resolve_param_name(pinfo, name2, cref->location);
363 /* Yes, so this is a parameter reference, no subfield */
368 /* No, so try to match as parameter name and subfield */
369 param = sql_fn_resolve_param_name(pinfo, name1, cref->location);
374 /* Single name, or parameter name followed by subfield */
375 param = sql_fn_resolve_param_name(pinfo, name1, cref->location);
379 return NULL; /* No match */
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
388 param = ParseFuncOrColumn(pstate,
389 list_make1(subfield),
399 * sql_fn_param_ref parser callback for ParamRefs ($n symbols)
402 sql_fn_param_ref(ParseState *pstate, ParamRef *pref)
404 SQLFunctionParseInfoPtr pinfo = (SQLFunctionParseInfoPtr) pstate->p_ref_hook_state;
405 int paramno = pref->number;
407 /* Check parameter number is valid */
408 if (paramno <= 0 || paramno > pinfo->nargs)
409 return NULL; /* unknown parameter number */
411 return sql_fn_make_param(pinfo, paramno, pref->location);
415 * sql_fn_make_param construct a Param node for the given paramno
418 sql_fn_make_param(SQLFunctionParseInfoPtr pinfo,
419 int paramno, int location)
423 param = makeNode(Param);
424 param->paramkind = PARAM_EXTERN;
425 param->paramid = paramno;
426 param->paramtype = pinfo->argtypes[paramno - 1];
427 param->paramtypmod = -1;
428 param->paramcollid = get_typcollation(param->paramtype);
429 param->location = location;
432 * If we have a function input collation, allow it to override the
433 * type-derived collation for parameter symbols. (XXX perhaps this should
434 * not happen if the type collation is not default?)
436 if (OidIsValid(pinfo->collation) && OidIsValid(param->paramcollid))
437 param->paramcollid = pinfo->collation;
439 return (Node *) param;
443 * Search for a function parameter of the given name; if there is one,
444 * construct and return a Param node for it. If not, return NULL.
445 * Helper function for sql_fn_post_column_ref.
448 sql_fn_resolve_param_name(SQLFunctionParseInfoPtr pinfo,
449 const char *paramname, int location)
453 if (pinfo->argnames == NULL)
456 for (i = 0; i < pinfo->nargs; i++)
458 if (pinfo->argnames[i] && strcmp(pinfo->argnames[i], paramname) == 0)
459 return sql_fn_make_param(pinfo, i + 1, location);
466 * Set up the per-query execution_state records for a SQL function.
468 * The input is a List of Lists of parsed and rewritten, but not planned,
469 * querytrees. The sublist structure denotes the original query boundaries.
472 init_execution_state(List *queryTree_list,
473 SQLFunctionCachePtr fcache,
477 execution_state *lasttages = NULL;
480 foreach(lc1, queryTree_list)
482 List *qtlist = (List *) lfirst(lc1);
483 execution_state *firstes = NULL;
484 execution_state *preves = NULL;
489 Query *queryTree = (Query *) lfirst(lc2);
491 execution_state *newes;
493 Assert(IsA(queryTree, Query));
495 /* Plan the query if needed */
496 if (queryTree->commandType == CMD_UTILITY)
497 stmt = queryTree->utilityStmt;
499 stmt = (Node *) pg_plan_query(queryTree,
500 fcache->readonly_func ? CURSOR_OPT_PARALLEL_OK : 0,
503 /* Precheck all commands for validity in a function */
504 if (IsA(stmt, TransactionStmt))
506 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
507 /* translator: %s is a SQL statement name */
508 errmsg("%s is not allowed in a SQL function",
509 CreateCommandTag(stmt))));
511 if (fcache->readonly_func && !CommandIsReadOnly(stmt))
513 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
514 /* translator: %s is a SQL statement name */
515 errmsg("%s is not allowed in a non-volatile function",
516 CreateCommandTag(stmt))));
518 if (IsInParallelMode() && !CommandIsReadOnly(stmt))
519 PreventCommandIfParallelMode(CreateCommandTag(stmt));
521 /* OK, build the execution_state for this query */
522 newes = (execution_state *) palloc(sizeof(execution_state));
524 preves->next = newes;
529 newes->status = F_EXEC_START;
530 newes->setsResult = false; /* might change below */
531 newes->lazyEval = false; /* might change below */
535 if (queryTree->canSetTag)
541 eslist = lappend(eslist, firstes);
545 * Mark the last canSetTag query as delivering the function result; then,
546 * if it is a plain SELECT, mark it for lazy evaluation. If it's not a
547 * SELECT we must always run it to completion.
549 * Note: at some point we might add additional criteria for whether to use
550 * lazy eval. However, we should prefer to use it whenever the function
551 * doesn't return set, since fetching more than one row is useless in that
554 * Note: don't set setsResult if the function returns VOID, as evidenced
555 * by not having made a junkfilter. This ensures we'll throw away any
556 * output from a utility statement that check_sql_fn_retval deemed to not
559 if (lasttages && fcache->junkFilter)
561 lasttages->setsResult = true;
563 IsA(lasttages->stmt, PlannedStmt))
565 PlannedStmt *ps = (PlannedStmt *) lasttages->stmt;
567 if (ps->commandType == CMD_SELECT &&
568 ps->utilityStmt == NULL &&
569 !ps->hasModifyingCTE)
570 fcache->lazyEval = lasttages->lazyEval = true;
578 * Initialize the SQLFunctionCache for a SQL function
581 init_sql_fcache(FmgrInfo *finfo, Oid collation, bool lazyEvalOK)
583 Oid foid = finfo->fn_oid;
584 MemoryContext fcontext;
585 MemoryContext oldcontext;
587 HeapTuple procedureTuple;
588 Form_pg_proc procedureStruct;
589 SQLFunctionCachePtr fcache;
590 List *raw_parsetree_list;
591 List *queryTree_list;
592 List *flat_query_list;
598 * Create memory context that holds all the SQLFunctionCache data. It
599 * must be a child of whatever context holds the FmgrInfo.
601 fcontext = AllocSetContextCreate(finfo->fn_mcxt,
603 ALLOCSET_DEFAULT_MINSIZE,
604 ALLOCSET_DEFAULT_INITSIZE,
605 ALLOCSET_DEFAULT_MAXSIZE);
607 oldcontext = MemoryContextSwitchTo(fcontext);
610 * Create the struct proper, link it to fcontext and fn_extra. Once this
611 * is done, we'll be able to recover the memory after failure, even if the
612 * FmgrInfo is long-lived.
614 fcache = (SQLFunctionCachePtr) palloc0(sizeof(SQLFunctionCache));
615 fcache->fcontext = fcontext;
616 finfo->fn_extra = (void *) fcache;
619 * get the procedure tuple corresponding to the given function Oid
621 procedureTuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(foid));
622 if (!HeapTupleIsValid(procedureTuple))
623 elog(ERROR, "cache lookup failed for function %u", foid);
624 procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple);
627 * copy function name immediately for use by error reporting callback
629 fcache->fname = pstrdup(NameStr(procedureStruct->proname));
632 * get the result type from the procedure tuple, and check for polymorphic
633 * result type; if so, find out the actual result type.
635 rettype = procedureStruct->prorettype;
637 if (IsPolymorphicType(rettype))
639 rettype = get_fn_expr_rettype(finfo);
640 if (rettype == InvalidOid) /* this probably should not happen */
642 (errcode(ERRCODE_DATATYPE_MISMATCH),
643 errmsg("could not determine actual result type for function declared to return type %s",
644 format_type_be(procedureStruct->prorettype))));
647 fcache->rettype = rettype;
649 /* Fetch the typlen and byval info for the result type */
650 get_typlenbyval(rettype, &fcache->typlen, &fcache->typbyval);
652 /* Remember whether we're returning setof something */
653 fcache->returnsSet = procedureStruct->proretset;
655 /* Remember if function is STABLE/IMMUTABLE */
656 fcache->readonly_func =
657 (procedureStruct->provolatile != PROVOLATILE_VOLATILE);
660 * We need the actual argument types to pass to the parser. Also make
661 * sure that parameter symbols are considered to have the function's
662 * resolved input collation.
664 fcache->pinfo = prepare_sql_fn_parse_info(procedureTuple,
669 * And of course we need the function body text.
671 tmp = SysCacheGetAttr(PROCOID,
676 elog(ERROR, "null prosrc for function %u", foid);
677 fcache->src = TextDatumGetCString(tmp);
680 * Parse and rewrite the queries in the function text. Use sublists to
681 * keep track of the original query boundaries. But we also build a
682 * "flat" list of the rewritten queries to pass to check_sql_fn_retval.
683 * This is because the last canSetTag query determines the result type
684 * independently of query boundaries --- and it might not be in the last
685 * sublist, for example if the last query rewrites to DO INSTEAD NOTHING.
686 * (It might not be unreasonable to throw an error in such a case, but
687 * this is the historical behavior and it doesn't seem worth changing.)
689 * Note: since parsing and planning is done in fcontext, we will generate
690 * a lot of cruft that lives as long as the fcache does. This is annoying
691 * but we'll not worry about it until the module is rewritten to use
694 raw_parsetree_list = pg_parse_query(fcache->src);
696 queryTree_list = NIL;
697 flat_query_list = NIL;
698 foreach(lc, raw_parsetree_list)
700 Node *parsetree = (Node *) lfirst(lc);
701 List *queryTree_sublist;
703 queryTree_sublist = pg_analyze_and_rewrite_params(parsetree,
705 (ParserSetupHook) sql_fn_parser_setup,
707 queryTree_list = lappend(queryTree_list, queryTree_sublist);
708 flat_query_list = list_concat(flat_query_list,
709 list_copy(queryTree_sublist));
713 * Check that the function returns the type it claims to. Although in
714 * simple cases this was already done when the function was defined, we
715 * have to recheck because database objects used in the function's queries
716 * might have changed type. We'd have to do it anyway if the function had
717 * any polymorphic arguments.
719 * Note: we set fcache->returnsTuple according to whether we are returning
720 * the whole tuple result or just a single column. In the latter case we
721 * clear returnsTuple because we need not act different from the scalar
722 * result case, even if it's a rowtype column. (However, we have to force
723 * lazy eval mode in that case; otherwise we'd need extra code to expand
724 * the rowtype column into multiple columns, since we have no way to
725 * notify the caller that it should do that.)
727 * check_sql_fn_retval will also construct a JunkFilter we can use to
728 * coerce the returned rowtype to the desired form (unless the result type
729 * is VOID, in which case there's nothing to coerce to).
731 fcache->returnsTuple = check_sql_fn_retval(foid,
735 &fcache->junkFilter);
737 if (fcache->returnsTuple)
739 /* Make sure output rowtype is properly blessed */
740 BlessTupleDesc(fcache->junkFilter->jf_resultSlot->tts_tupleDescriptor);
742 else if (fcache->returnsSet && type_is_rowtype(fcache->rettype))
745 * Returning rowtype as if it were scalar --- materialize won't work.
746 * Right now it's sufficient to override any caller preference for
747 * materialize mode, but to add more smarts in init_execution_state
748 * about this, we'd probably need a three-way flag instead of bool.
753 /* Finally, plan the queries */
754 fcache->func_state = init_execution_state(queryTree_list,
758 /* Mark fcache with time of creation to show it's valid */
759 fcache->lxid = MyProc->lxid;
760 fcache->subxid = GetCurrentSubTransactionId();
762 ReleaseSysCache(procedureTuple);
764 MemoryContextSwitchTo(oldcontext);
767 /* Start up execution of one execution_state node */
769 postquel_start(execution_state *es, SQLFunctionCachePtr fcache)
773 Assert(es->qd == NULL);
775 /* Caller should have ensured a suitable snapshot is active */
776 Assert(ActiveSnapshotSet());
779 * If this query produces the function result, send its output to the
780 * tuplestore; else discard any output.
784 DR_sqlfunction *myState;
786 dest = CreateDestReceiver(DestSQLFunction);
787 /* pass down the needed info to the dest receiver routines */
788 myState = (DR_sqlfunction *) dest;
789 Assert(myState->pub.mydest == DestSQLFunction);
790 myState->tstore = fcache->tstore;
791 myState->cxt = CurrentMemoryContext;
792 myState->filter = fcache->junkFilter;
795 dest = None_Receiver;
797 if (IsA(es->stmt, PlannedStmt))
798 es->qd = CreateQueryDesc((PlannedStmt *) es->stmt,
805 es->qd = CreateUtilityQueryDesc(es->stmt,
811 /* Utility commands don't need Executor. */
812 if (es->qd->utilitystmt == NULL)
815 * In lazyEval mode, do not let the executor set up an AfterTrigger
816 * context. This is necessary not just an optimization, because we
817 * mustn't exit from the function execution with a stacked
818 * AfterTrigger level still active. We are careful not to select
819 * lazyEval mode for any statement that could possibly queue triggers.
824 eflags = EXEC_FLAG_SKIP_TRIGGERS;
826 eflags = 0; /* default run-to-completion flags */
827 ExecutorStart(es->qd, eflags);
830 es->status = F_EXEC_RUN;
833 /* Run one execution_state; either to completion or to first result row */
834 /* Returns true if we ran to completion */
836 postquel_getnext(execution_state *es, SQLFunctionCachePtr fcache)
840 if (es->qd->utilitystmt)
842 /* ProcessUtility needs the PlannedStmt for DECLARE CURSOR */
843 ProcessUtility((es->qd->plannedstmt ?
844 (Node *) es->qd->plannedstmt :
845 es->qd->utilitystmt),
847 PROCESS_UTILITY_QUERY,
851 result = true; /* never stops early */
855 /* Run regular commands to completion unless lazyEval */
856 long count = (es->lazyEval) ? 1L : 0L;
858 ExecutorRun(es->qd, ForwardScanDirection, count);
861 * If we requested run to completion OR there was no tuple returned,
862 * command must be complete.
864 result = (count == 0L || es->qd->estate->es_processed == 0);
870 /* Shut down execution of one execution_state node */
872 postquel_end(execution_state *es)
874 /* mark status done to ensure we don't do ExecutorEnd twice */
875 es->status = F_EXEC_DONE;
877 /* Utility commands don't need Executor. */
878 if (es->qd->utilitystmt == NULL)
880 ExecutorFinish(es->qd);
884 (*es->qd->dest->rDestroy) (es->qd->dest);
886 FreeQueryDesc(es->qd);
890 /* Build ParamListInfo array representing current arguments */
892 postquel_sub_params(SQLFunctionCachePtr fcache,
893 FunctionCallInfo fcinfo)
895 int nargs = fcinfo->nargs;
899 ParamListInfo paramLI;
902 if (fcache->paramLI == NULL)
904 paramLI = (ParamListInfo)
905 palloc(offsetof(ParamListInfoData, params) +
906 nargs * sizeof(ParamExternData));
907 /* we have static list of params, so no hooks needed */
908 paramLI->paramFetch = NULL;
909 paramLI->paramFetchArg = NULL;
910 paramLI->parserSetup = NULL;
911 paramLI->parserSetupArg = NULL;
912 paramLI->numParams = nargs;
913 paramLI->paramMask = NULL;
914 fcache->paramLI = paramLI;
918 paramLI = fcache->paramLI;
919 Assert(paramLI->numParams == nargs);
922 for (i = 0; i < nargs; i++)
924 ParamExternData *prm = ¶mLI->params[i];
926 prm->value = fcinfo->arg[i];
927 prm->isnull = fcinfo->argnull[i];
929 prm->ptype = fcache->pinfo->argtypes[i];
933 fcache->paramLI = NULL;
937 * Extract the SQL function's value from a single result row. This is used
938 * both for scalar (non-set) functions and for each row of a lazy-eval set
942 postquel_get_single_result(TupleTableSlot *slot,
943 FunctionCallInfo fcinfo,
944 SQLFunctionCachePtr fcache,
945 MemoryContext resultcontext)
948 MemoryContext oldcontext;
951 * Set up to return the function value. For pass-by-reference datatypes,
952 * be sure to allocate the result in resultcontext, not the current memory
953 * context (which has query lifespan). We can't leave the data in the
954 * TupleTableSlot because we intend to clear the slot before returning.
956 oldcontext = MemoryContextSwitchTo(resultcontext);
958 if (fcache->returnsTuple)
960 /* We must return the whole tuple as a Datum. */
961 fcinfo->isnull = false;
962 value = ExecFetchSlotTupleDatum(slot);
967 * Returning a scalar, which we have to extract from the first column
968 * of the SELECT result, and then copy into result context if needed.
970 value = slot_getattr(slot, 1, &(fcinfo->isnull));
973 value = datumCopy(value, fcache->typbyval, fcache->typlen);
976 MemoryContextSwitchTo(oldcontext);
982 * fmgr_sql: function call manager for SQL functions
985 fmgr_sql(PG_FUNCTION_ARGS)
987 SQLFunctionCachePtr fcache;
988 ErrorContextCallback sqlerrcontext;
989 MemoryContext oldcontext;
993 bool pushed_snapshot;
995 TupleTableSlot *slot;
1001 * Setup error traceback support for ereport()
1003 sqlerrcontext.callback = sql_exec_error_callback;
1004 sqlerrcontext.arg = fcinfo->flinfo;
1005 sqlerrcontext.previous = error_context_stack;
1006 error_context_stack = &sqlerrcontext;
1008 /* Check call context */
1009 if (fcinfo->flinfo->fn_retset)
1011 ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
1014 * For simplicity, we require callers to support both set eval modes.
1015 * There are cases where we must use one or must use the other, and
1016 * it's not really worthwhile to postpone the check till we know. But
1017 * note we do not require caller to provide an expectedDesc.
1019 if (!rsi || !IsA(rsi, ReturnSetInfo) ||
1020 (rsi->allowedModes & SFRM_ValuePerCall) == 0 ||
1021 (rsi->allowedModes & SFRM_Materialize) == 0)
1023 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1024 errmsg("set-valued function called in context that cannot accept a set")));
1025 randomAccess = rsi->allowedModes & SFRM_Materialize_Random;
1026 lazyEvalOK = !(rsi->allowedModes & SFRM_Materialize_Preferred);
1030 randomAccess = false;
1035 * Initialize fcache (build plans) if first time through; or re-initialize
1036 * if the cache is stale.
1038 fcache = (SQLFunctionCachePtr) fcinfo->flinfo->fn_extra;
1042 if (fcache->lxid != MyProc->lxid ||
1043 !SubTransactionIsActive(fcache->subxid))
1045 /* It's stale; unlink and delete */
1046 fcinfo->flinfo->fn_extra = NULL;
1047 MemoryContextDelete(fcache->fcontext);
1054 init_sql_fcache(fcinfo->flinfo, PG_GET_COLLATION(), lazyEvalOK);
1055 fcache = (SQLFunctionCachePtr) fcinfo->flinfo->fn_extra;
1059 * Switch to context in which the fcache lives. This ensures that our
1060 * tuplestore etc will have sufficient lifetime. The sub-executor is
1061 * responsible for deleting per-tuple information. (XXX in the case of a
1062 * long-lived FmgrInfo, this policy represents more memory leakage, but
1063 * it's not entirely clear where to keep stuff instead.)
1065 oldcontext = MemoryContextSwitchTo(fcache->fcontext);
1068 * Find first unfinished query in function, and note whether it's the
1071 eslist = fcache->func_state;
1074 foreach(eslc, eslist)
1076 es = (execution_state *) lfirst(eslc);
1078 while (es && es->status == F_EXEC_DONE)
1089 * Convert params to appropriate format if starting a fresh execution. (If
1090 * continuing execution, we can re-use prior params.)
1092 if (is_first && es && es->status == F_EXEC_START)
1093 postquel_sub_params(fcache, fcinfo);
1096 * Build tuplestore to hold results, if we don't have one already. Note
1097 * it's in the query-lifespan context.
1099 if (!fcache->tstore)
1100 fcache->tstore = tuplestore_begin_heap(randomAccess, false, work_mem);
1103 * Execute each command in the function one after another until we either
1104 * run out of commands or get a result row from a lazily-evaluated SELECT.
1106 * Notes about snapshot management:
1108 * In a read-only function, we just use the surrounding query's snapshot.
1110 * In a non-read-only function, we rely on the fact that we'll never
1111 * suspend execution between queries of the function: the only reason to
1112 * suspend execution before completion is if we are returning a row from a
1113 * lazily-evaluated SELECT. So, when first entering this loop, we'll
1114 * either start a new query (and push a fresh snapshot) or re-establish
1115 * the active snapshot from the existing query descriptor. If we need to
1116 * start a new query in a subsequent execution of the loop, either we need
1117 * a fresh snapshot (and pushed_snapshot is false) or the existing
1118 * snapshot is on the active stack and we can just bump its command ID.
1120 pushed_snapshot = false;
1125 if (es->status == F_EXEC_START)
1128 * If not read-only, be sure to advance the command counter for
1129 * each command, so that all work to date in this transaction is
1130 * visible. Take a new snapshot if we don't have one yet,
1131 * otherwise just bump the command ID in the existing snapshot.
1133 if (!fcache->readonly_func)
1135 CommandCounterIncrement();
1136 if (!pushed_snapshot)
1138 PushActiveSnapshot(GetTransactionSnapshot());
1139 pushed_snapshot = true;
1142 UpdateActiveSnapshotCommandId();
1145 postquel_start(es, fcache);
1147 else if (!fcache->readonly_func && !pushed_snapshot)
1149 /* Re-establish active snapshot when re-entering function */
1150 PushActiveSnapshot(es->qd->snapshot);
1151 pushed_snapshot = true;
1154 completed = postquel_getnext(es, fcache);
1157 * If we ran the command to completion, we can shut it down now. Any
1158 * row(s) we need to return are safely stashed in the tuplestore, and
1159 * we want to be sure that, for example, AFTER triggers get fired
1160 * before we return anything. Also, if the function doesn't return
1161 * set, we can shut it down anyway because it must be a SELECT and we
1162 * don't care about fetching any more result rows.
1164 if (completed || !fcache->returnsSet)
1168 * Break from loop if we didn't shut down (implying we got a
1169 * lazily-evaluated row). Otherwise we'll press on till the whole
1170 * function is done, relying on the tuplestore to keep hold of the
1171 * data to eventually be returned. This is necessary since an
1172 * INSERT/UPDATE/DELETE RETURNING that sets the result might be
1173 * followed by additional rule-inserted commands, and we want to
1174 * finish doing all those commands before we return anything.
1176 if (es->status != F_EXEC_DONE)
1180 * Advance to next execution_state, which might be in the next list.
1187 break; /* end of function */
1189 es = (execution_state *) lfirst(eslc);
1192 * Flush the current snapshot so that we will take a new one for
1193 * the new query list. This ensures that new snaps are taken at
1194 * original-query boundaries, matching the behavior of interactive
1197 if (pushed_snapshot)
1199 PopActiveSnapshot();
1200 pushed_snapshot = false;
1206 * The tuplestore now contains whatever row(s) we are supposed to return.
1208 if (fcache->returnsSet)
1210 ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
1215 * If we stopped short of being done, we must have a lazy-eval
1218 Assert(es->lazyEval);
1219 /* Re-use the junkfilter's output slot to fetch back the tuple */
1220 Assert(fcache->junkFilter);
1221 slot = fcache->junkFilter->jf_resultSlot;
1222 if (!tuplestore_gettupleslot(fcache->tstore, true, false, slot))
1223 elog(ERROR, "failed to fetch lazy-eval tuple");
1224 /* Extract the result as a datum, and copy out from the slot */
1225 result = postquel_get_single_result(slot, fcinfo,
1226 fcache, oldcontext);
1227 /* Clear the tuplestore, but keep it for next time */
1228 /* NB: this might delete the slot's content, but we don't care */
1229 tuplestore_clear(fcache->tstore);
1232 * Let caller know we're not finished.
1234 rsi->isDone = ExprMultipleResult;
1237 * Ensure we will get shut down cleanly if the exprcontext is not
1238 * run to completion.
1240 if (!fcache->shutdown_reg)
1242 RegisterExprContextCallback(rsi->econtext,
1243 ShutdownSQLFunction,
1244 PointerGetDatum(fcache));
1245 fcache->shutdown_reg = true;
1248 else if (fcache->lazyEval)
1251 * We are done with a lazy evaluation. Clean up.
1253 tuplestore_clear(fcache->tstore);
1256 * Let caller know we're finished.
1258 rsi->isDone = ExprEndResult;
1260 fcinfo->isnull = true;
1263 /* Deregister shutdown callback, if we made one */
1264 if (fcache->shutdown_reg)
1266 UnregisterExprContextCallback(rsi->econtext,
1267 ShutdownSQLFunction,
1268 PointerGetDatum(fcache));
1269 fcache->shutdown_reg = false;
1275 * We are done with a non-lazy evaluation. Return whatever is in
1276 * the tuplestore. (It is now caller's responsibility to free the
1277 * tuplestore when done.)
1279 rsi->returnMode = SFRM_Materialize;
1280 rsi->setResult = fcache->tstore;
1281 fcache->tstore = NULL;
1282 /* must copy desc because execQual will free it */
1283 if (fcache->junkFilter)
1284 rsi->setDesc = CreateTupleDescCopy(fcache->junkFilter->jf_cleanTupType);
1286 fcinfo->isnull = true;
1289 /* Deregister shutdown callback, if we made one */
1290 if (fcache->shutdown_reg)
1292 UnregisterExprContextCallback(rsi->econtext,
1293 ShutdownSQLFunction,
1294 PointerGetDatum(fcache));
1295 fcache->shutdown_reg = false;
1302 * Non-set function. If we got a row, return it; else return NULL.
1304 if (fcache->junkFilter)
1306 /* Re-use the junkfilter's output slot to fetch back the tuple */
1307 slot = fcache->junkFilter->jf_resultSlot;
1308 if (tuplestore_gettupleslot(fcache->tstore, true, false, slot))
1309 result = postquel_get_single_result(slot, fcinfo,
1310 fcache, oldcontext);
1313 fcinfo->isnull = true;
1319 /* Should only get here for VOID functions */
1320 Assert(fcache->rettype == VOIDOID);
1321 fcinfo->isnull = true;
1325 /* Clear the tuplestore, but keep it for next time */
1326 tuplestore_clear(fcache->tstore);
1329 /* Pop snapshot if we have pushed one */
1330 if (pushed_snapshot)
1331 PopActiveSnapshot();
1334 * If we've gone through every command in the function, we are done. Reset
1335 * the execution states to start over again on next call.
1339 foreach(eslc, fcache->func_state)
1341 es = (execution_state *) lfirst(eslc);
1344 es->status = F_EXEC_START;
1350 error_context_stack = sqlerrcontext.previous;
1352 MemoryContextSwitchTo(oldcontext);
1359 * error context callback to let us supply a call-stack traceback
1362 sql_exec_error_callback(void *arg)
1364 FmgrInfo *flinfo = (FmgrInfo *) arg;
1365 SQLFunctionCachePtr fcache = (SQLFunctionCachePtr) flinfo->fn_extra;
1366 int syntaxerrposition;
1369 * We can do nothing useful if init_sql_fcache() didn't get as far as
1370 * saving the function name
1372 if (fcache == NULL || fcache->fname == NULL)
1376 * If there is a syntax error position, convert to internal syntax error
1378 syntaxerrposition = geterrposition();
1379 if (syntaxerrposition > 0 && fcache->src != NULL)
1382 internalerrposition(syntaxerrposition);
1383 internalerrquery(fcache->src);
1387 * Try to determine where in the function we failed. If there is a query
1388 * with non-null QueryDesc, finger it. (We check this rather than looking
1389 * for F_EXEC_RUN state, so that errors during ExecutorStart or
1390 * ExecutorEnd are blamed on the appropriate query; see postquel_start and
1393 if (fcache->func_state)
1395 execution_state *es;
1401 foreach(lc, fcache->func_state)
1403 es = (execution_state *) lfirst(lc);
1408 errcontext("SQL function \"%s\" statement %d",
1409 fcache->fname, query_num);
1421 * couldn't identify a running query; might be function entry,
1422 * function exit, or between queries.
1424 errcontext("SQL function \"%s\"", fcache->fname);
1430 * Assume we failed during init_sql_fcache(). (It's possible that the
1431 * function actually has an empty body, but in that case we may as
1432 * well report all errors as being "during startup".)
1434 errcontext("SQL function \"%s\" during startup", fcache->fname);
1440 * callback function in case a function-returning-set needs to be shut down
1441 * before it has been run to completion
1444 ShutdownSQLFunction(Datum arg)
1446 SQLFunctionCachePtr fcache = (SQLFunctionCachePtr) DatumGetPointer(arg);
1447 execution_state *es;
1450 foreach(lc, fcache->func_state)
1452 es = (execution_state *) lfirst(lc);
1455 /* Shut down anything still running */
1456 if (es->status == F_EXEC_RUN)
1458 /* Re-establish active snapshot for any called functions */
1459 if (!fcache->readonly_func)
1460 PushActiveSnapshot(es->qd->snapshot);
1464 if (!fcache->readonly_func)
1465 PopActiveSnapshot();
1468 /* Reset states to START in case we're called again */
1469 es->status = F_EXEC_START;
1474 /* Release tuplestore if we have one */
1476 tuplestore_end(fcache->tstore);
1477 fcache->tstore = NULL;
1479 /* execUtils will deregister the callback... */
1480 fcache->shutdown_reg = false;
1485 * check_sql_fn_retval() -- check return value of a list of sql parse trees.
1487 * The return value of a sql function is the value returned by the last
1488 * canSetTag query in the function. We do some ad-hoc type checking here
1489 * to be sure that the user is returning the type he claims. There are
1490 * also a couple of strange-looking features to assist callers in dealing
1491 * with allowed special cases, such as binary-compatible result types.
1493 * For a polymorphic function the passed rettype must be the actual resolved
1494 * output type of the function; we should never see a polymorphic pseudotype
1495 * such as ANYELEMENT as rettype. (This means we can't check the type during
1496 * function definition of a polymorphic function.)
1498 * This function returns true if the sql function returns the entire tuple
1499 * result of its final statement, or false if it returns just the first column
1500 * result of that statement. It throws an error if the final statement doesn't
1501 * return the right type at all.
1503 * Note that because we allow "SELECT rowtype_expression", the result can be
1504 * false even when the declared function return type is a rowtype.
1506 * If modifyTargetList isn't NULL, the function will modify the final
1507 * statement's targetlist in two cases:
1508 * (1) if the tlist returns values that are binary-coercible to the expected
1509 * type rather than being exactly the expected type. RelabelType nodes will
1510 * be inserted to make the result types match exactly.
1511 * (2) if there are dropped columns in the declared result rowtype. NULL
1512 * output columns will be inserted in the tlist to match them.
1513 * (Obviously the caller must pass a parsetree that is okay to modify when
1514 * using this flag.) Note that this flag does not affect whether the tlist is
1515 * considered to be a legal match to the result type, only how we react to
1516 * allowed not-exact-match cases. *modifyTargetList will be set true iff
1517 * we had to make any "dangerous" changes that could modify the semantics of
1518 * the statement. If it is set true, the caller should not use the modified
1519 * statement, but for simplicity we apply the changes anyway.
1521 * If junkFilter isn't NULL, then *junkFilter is set to a JunkFilter defined
1522 * to convert the function's tuple result to the correct output tuple type.
1523 * Exception: if the function is defined to return VOID then *junkFilter is
1527 check_sql_fn_retval(Oid func_id, Oid rettype, List *queryTreeList,
1528 bool *modifyTargetList,
1529 JunkFilter **junkFilter)
1539 AssertArg(!IsPolymorphicType(rettype));
1541 if (modifyTargetList)
1542 *modifyTargetList = false; /* initialize for no change */
1544 *junkFilter = NULL; /* initialize in case of VOID result */
1547 * Find the last canSetTag query in the list. This isn't necessarily the
1548 * last parsetree, because rule rewriting can insert queries after what
1552 foreach(lc, queryTreeList)
1554 Query *q = (Query *) lfirst(lc);
1561 * If it's a plain SELECT, it returns whatever the targetlist says.
1562 * Otherwise, if it's INSERT/UPDATE/DELETE with RETURNING, it returns
1563 * that. Otherwise, the function return type must be VOID.
1565 * Note: eventually replace this test with QueryReturnsTuples? We'd need
1566 * a more general method of determining the output type, though. Also, it
1567 * seems too dangerous to consider FETCH or EXECUTE as returning a
1568 * determinable rowtype, since they depend on relatively short-lived
1572 parse->commandType == CMD_SELECT &&
1573 parse->utilityStmt == NULL)
1575 tlist_ptr = &parse->targetList;
1576 tlist = parse->targetList;
1579 (parse->commandType == CMD_INSERT ||
1580 parse->commandType == CMD_UPDATE ||
1581 parse->commandType == CMD_DELETE) &&
1582 parse->returningList)
1584 tlist_ptr = &parse->returningList;
1585 tlist = parse->returningList;
1589 /* Empty function body, or last statement is a utility command */
1590 if (rettype != VOIDOID)
1592 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1593 errmsg("return type mismatch in function declared to return %s",
1594 format_type_be(rettype)),
1595 errdetail("Function's final statement must be SELECT or INSERT/UPDATE/DELETE RETURNING.")));
1600 * OK, check that the targetlist returns something matching the declared
1601 * type. (We used to insist that the declared type not be VOID in this
1602 * case, but that makes it hard to write a void function that exits after
1603 * calling another void function. Instead, we insist that the tlist
1604 * return void ... so void is treated as if it were a scalar type below.)
1608 * Count the non-junk entries in the result targetlist.
1610 tlistlen = ExecCleanTargetListLength(tlist);
1612 fn_typtype = get_typtype(rettype);
1614 if (fn_typtype == TYPTYPE_BASE ||
1615 fn_typtype == TYPTYPE_DOMAIN ||
1616 fn_typtype == TYPTYPE_ENUM ||
1617 fn_typtype == TYPTYPE_RANGE ||
1621 * For scalar-type returns, the target list must have exactly one
1622 * non-junk entry, and its type must agree with what the user
1623 * declared; except we allow binary-compatible types too.
1629 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1630 errmsg("return type mismatch in function declared to return %s",
1631 format_type_be(rettype)),
1632 errdetail("Final statement must return exactly one column.")));
1634 /* We assume here that non-junk TLEs must come first in tlists */
1635 tle = (TargetEntry *) linitial(tlist);
1636 Assert(!tle->resjunk);
1638 restype = exprType((Node *) tle->expr);
1639 if (!IsBinaryCoercible(restype, rettype))
1641 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1642 errmsg("return type mismatch in function declared to return %s",
1643 format_type_be(rettype)),
1644 errdetail("Actual return type is %s.",
1645 format_type_be(restype))));
1646 if (modifyTargetList && restype != rettype)
1648 tle->expr = (Expr *) makeRelabelType(tle->expr,
1651 get_typcollation(rettype),
1652 COERCE_IMPLICIT_CAST);
1653 /* Relabel is dangerous if TLE is a sort/group or setop column */
1654 if (tle->ressortgroupref != 0 || parse->setOperations)
1655 *modifyTargetList = true;
1658 /* Set up junk filter if needed */
1660 *junkFilter = ExecInitJunkFilter(tlist, false, NULL);
1662 else if (fn_typtype == TYPTYPE_COMPOSITE || rettype == RECORDOID)
1664 /* Returns a rowtype */
1666 int tupnatts; /* physical number of columns in tuple */
1667 int tuplogcols; /* # of nondeleted columns in tuple */
1668 int colindex; /* physical column index */
1669 List *newtlist; /* new non-junk tlist entries */
1670 List *junkattrs; /* new junk tlist entries */
1673 * If the target list is of length 1, and the type of the varnode in
1674 * the target list matches the declared return type, this is okay.
1675 * This can happen, for example, where the body of the function is
1676 * 'SELECT func2()', where func2 has the same composite return type as
1677 * the function that's calling it.
1679 * XXX Note that if rettype is RECORD, the IsBinaryCoercible check
1680 * will succeed for any composite restype. For the moment we rely on
1681 * runtime type checking to catch any discrepancy, but it'd be nice to
1682 * do better at parse time.
1686 TargetEntry *tle = (TargetEntry *) linitial(tlist);
1688 Assert(!tle->resjunk);
1689 restype = exprType((Node *) tle->expr);
1690 if (IsBinaryCoercible(restype, rettype))
1692 if (modifyTargetList && restype != rettype)
1694 tle->expr = (Expr *) makeRelabelType(tle->expr,
1697 get_typcollation(rettype),
1698 COERCE_IMPLICIT_CAST);
1699 /* Relabel is dangerous if sort/group or setop column */
1700 if (tle->ressortgroupref != 0 || parse->setOperations)
1701 *modifyTargetList = true;
1703 /* Set up junk filter if needed */
1705 *junkFilter = ExecInitJunkFilter(tlist, false, NULL);
1706 return false; /* NOT returning whole tuple */
1710 /* Is the rowtype fixed, or determined only at runtime? */
1711 if (get_func_result_type(func_id, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
1714 * Assume we are returning the whole tuple. Crosschecking against
1715 * what the caller expects will happen at runtime.
1718 *junkFilter = ExecInitJunkFilter(tlist, false, NULL);
1724 * Verify that the targetlist matches the return tuple type. We scan
1725 * the non-deleted attributes to ensure that they match the datatypes
1726 * of the non-resjunk columns. For deleted attributes, insert NULL
1727 * result columns if the caller asked for that.
1729 tupnatts = tupdesc->natts;
1730 tuplogcols = 0; /* we'll count nondeleted cols as we go */
1732 newtlist = NIL; /* these are only used if modifyTargetList */
1737 TargetEntry *tle = (TargetEntry *) lfirst(lc);
1738 Form_pg_attribute attr;
1744 if (modifyTargetList)
1745 junkattrs = lappend(junkattrs, tle);
1752 if (colindex > tupnatts)
1754 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1755 errmsg("return type mismatch in function declared to return %s",
1756 format_type_be(rettype)),
1757 errdetail("Final statement returns too many columns.")));
1758 attr = tupdesc->attrs[colindex - 1];
1759 if (attr->attisdropped && modifyTargetList)
1763 /* The type of the null we insert isn't important */
1764 null_expr = (Expr *) makeConst(INT4OID,
1771 newtlist = lappend(newtlist,
1772 makeTargetEntry(null_expr,
1776 /* NULL insertion is dangerous in a setop */
1777 if (parse->setOperations)
1778 *modifyTargetList = true;
1780 } while (attr->attisdropped);
1783 tletype = exprType((Node *) tle->expr);
1784 atttype = attr->atttypid;
1785 if (!IsBinaryCoercible(tletype, atttype))
1787 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1788 errmsg("return type mismatch in function declared to return %s",
1789 format_type_be(rettype)),
1790 errdetail("Final statement returns %s instead of %s at column %d.",
1791 format_type_be(tletype),
1792 format_type_be(atttype),
1794 if (modifyTargetList)
1796 if (tletype != atttype)
1798 tle->expr = (Expr *) makeRelabelType(tle->expr,
1801 get_typcollation(atttype),
1802 COERCE_IMPLICIT_CAST);
1803 /* Relabel is dangerous if sort/group or setop column */
1804 if (tle->ressortgroupref != 0 || parse->setOperations)
1805 *modifyTargetList = true;
1807 tle->resno = colindex;
1808 newtlist = lappend(newtlist, tle);
1812 /* remaining columns in tupdesc had better all be dropped */
1813 for (colindex++; colindex <= tupnatts; colindex++)
1815 if (!tupdesc->attrs[colindex - 1]->attisdropped)
1817 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1818 errmsg("return type mismatch in function declared to return %s",
1819 format_type_be(rettype)),
1820 errdetail("Final statement returns too few columns.")));
1821 if (modifyTargetList)
1825 /* The type of the null we insert isn't important */
1826 null_expr = (Expr *) makeConst(INT4OID,
1833 newtlist = lappend(newtlist,
1834 makeTargetEntry(null_expr,
1838 /* NULL insertion is dangerous in a setop */
1839 if (parse->setOperations)
1840 *modifyTargetList = true;
1844 if (modifyTargetList)
1846 /* ensure resjunk columns are numbered correctly */
1847 foreach(lc, junkattrs)
1849 TargetEntry *tle = (TargetEntry *) lfirst(lc);
1851 tle->resno = colindex++;
1853 /* replace the tlist with the modified one */
1854 *tlist_ptr = list_concat(newtlist, junkattrs);
1857 /* Set up junk filter if needed */
1859 *junkFilter = ExecInitJunkFilterConversion(tlist,
1860 CreateTupleDescCopy(tupdesc),
1863 /* Report that we are returning entire tuple result */
1868 (errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
1869 errmsg("return type %s is not supported for SQL functions",
1870 format_type_be(rettype))));
1877 * CreateSQLFunctionDestReceiver -- create a suitable DestReceiver object
1880 CreateSQLFunctionDestReceiver(void)
1882 DR_sqlfunction *self = (DR_sqlfunction *) palloc0(sizeof(DR_sqlfunction));
1884 self->pub.receiveSlot = sqlfunction_receive;
1885 self->pub.rStartup = sqlfunction_startup;
1886 self->pub.rShutdown = sqlfunction_shutdown;
1887 self->pub.rDestroy = sqlfunction_destroy;
1888 self->pub.mydest = DestSQLFunction;
1890 /* private fields will be set by postquel_start */
1892 return (DestReceiver *) self;
1896 * sqlfunction_startup --- executor startup
1899 sqlfunction_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
1905 * sqlfunction_receive --- receive one tuple
1908 sqlfunction_receive(TupleTableSlot *slot, DestReceiver *self)
1910 DR_sqlfunction *myState = (DR_sqlfunction *) self;
1912 /* Filter tuple as needed */
1913 slot = ExecFilterJunk(myState->filter, slot);
1915 /* Store the filtered tuple into the tuplestore */
1916 tuplestore_puttupleslot(myState->tstore, slot);
1920 * sqlfunction_shutdown --- executor end
1923 sqlfunction_shutdown(DestReceiver *self)
1929 * sqlfunction_destroy --- release DestReceiver object
1932 sqlfunction_destroy(DestReceiver *self)