1 /*-------------------------------------------------------------------------
4 * top level executor interface routines
11 * The old ExecutorMain() has been replaced by ExecutorStart(),
12 * ExecutorRun() and ExecutorEnd()
14 * These three procedures are the external interfaces to the executor.
15 * In each case, the query descriptor is required as an argument.
17 * ExecutorStart() must be called at the beginning of execution of any
18 * query plan and ExecutorEnd() should always be called at the end of
19 * execution of a plan.
21 * ExecutorRun accepts direction and count arguments that specify whether
22 * the plan is to be executed forwards, backwards, and for how many tuples.
24 * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
25 * Portions Copyright (c) 1994, Regents of the University of California
29 * $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.215 2003/08/06 17:46:45 tgl Exp $
31 *-------------------------------------------------------------------------
35 #include "access/heapam.h"
36 #include "catalog/heap.h"
37 #include "catalog/namespace.h"
38 #include "commands/tablecmds.h"
39 #include "commands/trigger.h"
40 #include "executor/execdebug.h"
41 #include "executor/execdefs.h"
42 #include "miscadmin.h"
43 #include "optimizer/var.h"
44 #include "parser/parsetree.h"
45 #include "utils/acl.h"
46 #include "utils/lsyscache.h"
49 typedef struct execRowMark
56 typedef struct evalPlanQual
61 struct evalPlanQual *next; /* stack of active PlanQual plans */
62 struct evalPlanQual *free; /* list of free PlanQual plans */
65 /* decls for local routines only used within this module */
66 static void InitPlan(QueryDesc *queryDesc, bool explainOnly);
67 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
68 Index resultRelationIndex,
71 static TupleTableSlot *ExecutePlan(EState *estate, PlanState * planstate,
74 ScanDirection direction,
76 static void ExecSelect(TupleTableSlot *slot,
79 static void ExecInsert(TupleTableSlot *slot, ItemPointer tupleid,
81 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
83 static void ExecUpdate(TupleTableSlot *slot, ItemPointer tupleid,
85 static TupleTableSlot *EvalPlanQualNext(EState *estate);
86 static void EndEvalPlanQual(EState *estate);
87 static void ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation);
88 static void ExecCheckXactReadOnly(Query *parsetree, CmdType operation);
89 static void EvalPlanQualStart(evalPlanQual *epq, EState *estate,
90 evalPlanQual *priorepq);
91 static void EvalPlanQualStop(evalPlanQual *epq);
93 /* end of local decls */
96 /* ----------------------------------------------------------------
99 * This routine must be called at the beginning of any execution of any
102 * Takes a QueryDesc previously created by CreateQueryDesc (it's not real
103 * clear why we bother to separate the two functions, but...). The tupDesc
104 * field of the QueryDesc is filled in to describe the tuples that will be
105 * returned, and the internal fields (estate and planstate) are set up.
107 * If explainOnly is true, we are not actually intending to run the plan,
108 * only to set up for EXPLAIN; so skip unwanted side-effects.
110 * NB: the CurrentMemoryContext when this is called will become the parent
111 * of the per-query context used for this Executor invocation.
112 * ----------------------------------------------------------------
115 ExecutorStart(QueryDesc *queryDesc, bool explainOnly)
118 MemoryContext oldcontext;
120 /* sanity checks: queryDesc must not be started already */
121 Assert(queryDesc != NULL);
122 Assert(queryDesc->estate == NULL);
125 * If the transaction is read-only, we need to check if any writes are
126 * planned to non-temporary tables.
129 ExecCheckXactReadOnly(queryDesc->parsetree, queryDesc->operation);
132 * Build EState, switch into per-query memory context for startup.
134 estate = CreateExecutorState();
135 queryDesc->estate = estate;
137 oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
140 * Fill in parameters, if any, from queryDesc
142 estate->es_param_list_info = queryDesc->params;
144 if (queryDesc->plantree->nParamExec > 0)
145 estate->es_param_exec_vals = (ParamExecData *)
146 palloc0(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
148 estate->es_instrument = queryDesc->doInstrument;
151 * Make our own private copy of the current query snapshot data.
153 * This "freezes" our idea of which tuples are good and which are not for
154 * the life of this query, even if it outlives the current command and
157 estate->es_snapshot = CopyQuerySnapshot();
160 * Initialize the plan state tree
162 InitPlan(queryDesc, explainOnly);
164 MemoryContextSwitchTo(oldcontext);
167 /* ----------------------------------------------------------------
170 * This is the main routine of the executor module. It accepts
171 * the query descriptor from the traffic cop and executes the
174 * ExecutorStart must have been called already.
176 * If direction is NoMovementScanDirection then nothing is done
177 * except to start up/shut down the destination. Otherwise,
178 * we retrieve up to 'count' tuples in the specified direction.
180 * Note: count = 0 is interpreted as no portal limit, i.e., run to
183 * ----------------------------------------------------------------
186 ExecutorRun(QueryDesc *queryDesc,
187 ScanDirection direction, long count)
192 TupleTableSlot *result;
193 MemoryContext oldcontext;
196 Assert(queryDesc != NULL);
198 estate = queryDesc->estate;
200 Assert(estate != NULL);
203 * Switch into per-query memory context
205 oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
208 * extract information from the query descriptor and the query
211 operation = queryDesc->operation;
212 dest = queryDesc->dest;
215 * startup tuple receiver
217 estate->es_processed = 0;
218 estate->es_lastoid = InvalidOid;
220 (*dest->rStartup) (dest, operation, queryDesc->tupDesc);
225 if (direction == NoMovementScanDirection)
228 result = ExecutePlan(estate,
229 queryDesc->planstate,
238 (*dest->rShutdown) (dest);
240 MemoryContextSwitchTo(oldcontext);
245 /* ----------------------------------------------------------------
248 * This routine must be called at the end of execution of any
250 * ----------------------------------------------------------------
253 ExecutorEnd(QueryDesc *queryDesc)
256 MemoryContext oldcontext;
259 Assert(queryDesc != NULL);
261 estate = queryDesc->estate;
263 Assert(estate != NULL);
266 * Switch into per-query memory context to run ExecEndPlan
268 oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
270 ExecEndPlan(queryDesc->planstate, estate);
273 * Must switch out of context before destroying it
275 MemoryContextSwitchTo(oldcontext);
278 * Release EState and per-query memory context. This should release
279 * everything the executor has allocated.
281 FreeExecutorState(estate);
283 /* Reset queryDesc fields that no longer point to anything */
284 queryDesc->tupDesc = NULL;
285 queryDesc->estate = NULL;
286 queryDesc->planstate = NULL;
289 /* ----------------------------------------------------------------
292 * This routine may be called on an open queryDesc to rewind it
294 * ----------------------------------------------------------------
297 ExecutorRewind(QueryDesc *queryDesc)
300 MemoryContext oldcontext;
303 Assert(queryDesc != NULL);
305 estate = queryDesc->estate;
307 Assert(estate != NULL);
309 /* It's probably not sensible to rescan updating queries */
310 Assert(queryDesc->operation == CMD_SELECT);
313 * Switch into per-query memory context
315 oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
320 ExecReScan(queryDesc->planstate, NULL);
322 MemoryContextSwitchTo(oldcontext);
328 * Check access permissions for all relations listed in a range table.
331 ExecCheckRTPerms(List *rangeTable, CmdType operation)
335 foreach(lp, rangeTable)
337 RangeTblEntry *rte = lfirst(lp);
339 ExecCheckRTEPerms(rte, operation);
345 * Check access permissions for a single RTE.
348 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
352 AclResult aclcheck_result;
355 * If it's a subquery, recursively examine its rangetable.
357 if (rte->rtekind == RTE_SUBQUERY)
359 ExecCheckRTPerms(rte->subquery->rtable, operation);
364 * Otherwise, only plain-relation RTEs need to be checked here.
365 * Function RTEs are checked by init_fcache when the function is
366 * prepared for execution. Join and special RTEs need no checks.
368 if (rte->rtekind != RTE_RELATION)
374 * userid to check as: current user unless we have a setuid
377 * Note: GetUserId() is presently fast enough that there's no harm in
378 * calling it separately for each RTE. If that stops being true, we
379 * could call it once in ExecCheckRTPerms and pass the userid down
380 * from there. But for now, no need for the extra clutter.
382 userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
384 #define CHECK(MODE) pg_class_aclcheck(relOid, userid, MODE)
386 if (rte->checkForRead)
388 aclcheck_result = CHECK(ACL_SELECT);
389 if (aclcheck_result != ACLCHECK_OK)
390 aclcheck_error(aclcheck_result, ACL_KIND_CLASS,
391 get_rel_name(relOid));
394 if (rte->checkForWrite)
397 * Note: write access in a SELECT context means SELECT FOR UPDATE.
398 * Right now we don't distinguish that from true update as far as
399 * permissions checks are concerned.
404 aclcheck_result = CHECK(ACL_INSERT);
408 aclcheck_result = CHECK(ACL_UPDATE);
411 aclcheck_result = CHECK(ACL_DELETE);
414 elog(ERROR, "unrecognized operation code: %d",
416 aclcheck_result = ACLCHECK_OK; /* keep compiler quiet */
419 if (aclcheck_result != ACLCHECK_OK)
420 aclcheck_error(aclcheck_result, ACL_KIND_CLASS,
421 get_rel_name(relOid));
426 ExecCheckXactReadOnly(Query *parsetree, CmdType operation)
431 /* CREATE TABLE AS or SELECT INTO */
432 if (operation == CMD_SELECT && parsetree->into != NULL)
435 if (operation == CMD_DELETE || operation == CMD_INSERT
436 || operation == CMD_UPDATE)
440 foreach(lp, parsetree->rtable)
442 RangeTblEntry *rte = lfirst(lp);
444 if (rte->rtekind != RTE_RELATION)
447 if (!rte->checkForWrite)
450 if (isTempNamespace(get_rel_namespace(rte->relid)))
461 (errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION),
462 errmsg("transaction is read-only")));
466 /* ----------------------------------------------------------------
469 * Initializes the query plan: open files, allocate storage
470 * and start up the rule manager
471 * ----------------------------------------------------------------
474 InitPlan(QueryDesc *queryDesc, bool explainOnly)
476 CmdType operation = queryDesc->operation;
477 Query *parseTree = queryDesc->parsetree;
478 Plan *plan = queryDesc->plantree;
479 EState *estate = queryDesc->estate;
480 PlanState *planstate;
482 Relation intoRelationDesc;
487 * Do permissions checks. It's sufficient to examine the query's top
488 * rangetable here --- subplan RTEs will be checked during
491 ExecCheckRTPerms(parseTree->rtable, operation);
494 * get information from query descriptor
496 rangeTable = parseTree->rtable;
499 * initialize the node's execution state
501 estate->es_range_table = rangeTable;
504 * if there is a result relation, initialize result relation stuff
506 if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
508 List *resultRelations = parseTree->resultRelations;
509 int numResultRelations;
510 ResultRelInfo *resultRelInfos;
512 if (resultRelations != NIL)
515 * Multiple result relations (due to inheritance)
516 * parseTree->resultRelations identifies them all
518 ResultRelInfo *resultRelInfo;
520 numResultRelations = length(resultRelations);
521 resultRelInfos = (ResultRelInfo *)
522 palloc(numResultRelations * sizeof(ResultRelInfo));
523 resultRelInfo = resultRelInfos;
524 while (resultRelations != NIL)
526 initResultRelInfo(resultRelInfo,
527 lfirsti(resultRelations),
531 resultRelations = lnext(resultRelations);
537 * Single result relation identified by
538 * parseTree->resultRelation
540 numResultRelations = 1;
541 resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
542 initResultRelInfo(resultRelInfos,
543 parseTree->resultRelation,
548 estate->es_result_relations = resultRelInfos;
549 estate->es_num_result_relations = numResultRelations;
550 /* Initialize to first or only result rel */
551 estate->es_result_relation_info = resultRelInfos;
556 * if no result relation, then set state appropriately
558 estate->es_result_relations = NULL;
559 estate->es_num_result_relations = 0;
560 estate->es_result_relation_info = NULL;
564 * Detect whether we're doing SELECT INTO. If so, set the force_oids
565 * flag appropriately so that the plan tree will be initialized with
566 * the correct tuple descriptors.
568 do_select_into = false;
570 if (operation == CMD_SELECT && parseTree->into != NULL)
572 do_select_into = true;
575 * For now, always create OIDs in SELECT INTO; this is for
576 * backwards compatibility with pre-7.3 behavior. Eventually we
577 * might want to allow the user to choose.
579 estate->es_force_oids = true;
583 * Have to lock relations selected for update
585 estate->es_rowMark = NIL;
586 if (parseTree->rowMarks != NIL)
590 foreach(l, parseTree->rowMarks)
592 Index rti = lfirsti(l);
593 Oid relid = getrelid(rti, rangeTable);
597 relation = heap_open(relid, RowShareLock);
598 erm = (execRowMark *) palloc(sizeof(execRowMark));
599 erm->relation = relation;
601 snprintf(erm->resname, sizeof(erm->resname), "ctid%u", rti);
602 estate->es_rowMark = lappend(estate->es_rowMark, erm);
607 * initialize the executor "tuple" table. We need slots for all the
608 * plan nodes, plus possibly output slots for the junkfilter(s). At
609 * this point we aren't sure if we need junkfilters, so just add slots
610 * for them unconditionally.
613 int nSlots = ExecCountSlotsNode(plan);
615 if (parseTree->resultRelations != NIL)
616 nSlots += length(parseTree->resultRelations);
619 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
622 /* mark EvalPlanQual not active */
623 estate->es_topPlan = plan;
624 estate->es_evalPlanQual = NULL;
625 estate->es_evTupleNull = NULL;
626 estate->es_evTuple = NULL;
627 estate->es_useEvalPlan = false;
630 * initialize the private state information for all the nodes in the
631 * query tree. This opens files, allocates storage and leaves us
632 * ready to start processing tuples.
634 planstate = ExecInitNode(plan, estate);
637 * Get the tuple descriptor describing the type of tuples to return.
638 * (this is especially important if we are creating a relation with
641 tupType = ExecGetResultType(planstate);
644 * Initialize the junk filter if needed. SELECT and INSERT queries
645 * need a filter if there are any junk attrs in the tlist. INSERT and
646 * SELECT INTO also need a filter if the top plan node is a scan node
647 * that's not doing projection (else we'll be scribbling on the scan
648 * tuple!) UPDATE and DELETE always need a filter, since there's
649 * always a junk 'ctid' attribute present --- no need to look first.
652 bool junk_filter_needed = false;
659 foreach(tlist, plan->targetlist)
661 TargetEntry *tle = (TargetEntry *) lfirst(tlist);
663 if (tle->resdom->resjunk)
665 junk_filter_needed = true;
669 if (!junk_filter_needed &&
670 (operation == CMD_INSERT || do_select_into))
672 if (IsA(planstate, SeqScanState) ||
673 IsA(planstate, IndexScanState) ||
674 IsA(planstate, TidScanState) ||
675 IsA(planstate, SubqueryScanState) ||
676 IsA(planstate, FunctionScanState))
678 if (planstate->ps_ProjInfo == NULL)
679 junk_filter_needed = true;
685 junk_filter_needed = true;
691 if (junk_filter_needed)
694 * If there are multiple result relations, each one needs its
695 * own junk filter. Note this is only possible for
696 * UPDATE/DELETE, so we can't be fooled by some needing a
697 * filter and some not.
699 if (parseTree->resultRelations != NIL)
701 PlanState **appendplans;
703 ResultRelInfo *resultRelInfo;
706 /* Top plan had better be an Append here. */
707 Assert(IsA(plan, Append));
708 Assert(((Append *) plan)->isTarget);
709 Assert(IsA(planstate, AppendState));
710 appendplans = ((AppendState *) planstate)->appendplans;
711 as_nplans = ((AppendState *) planstate)->as_nplans;
712 Assert(as_nplans == estate->es_num_result_relations);
713 resultRelInfo = estate->es_result_relations;
714 for (i = 0; i < as_nplans; i++)
716 PlanState *subplan = appendplans[i];
719 j = ExecInitJunkFilter(subplan->plan->targetlist,
720 ExecGetResultType(subplan),
721 ExecAllocTableSlot(estate->es_tupleTable));
722 resultRelInfo->ri_junkFilter = j;
727 * Set active junkfilter too; at this point ExecInitAppend
728 * has already selected an active result relation...
730 estate->es_junkFilter =
731 estate->es_result_relation_info->ri_junkFilter;
735 /* Normal case with just one JunkFilter */
738 j = ExecInitJunkFilter(planstate->plan->targetlist,
740 ExecAllocTableSlot(estate->es_tupleTable));
741 estate->es_junkFilter = j;
742 if (estate->es_result_relation_info)
743 estate->es_result_relation_info->ri_junkFilter = j;
745 /* For SELECT, want to return the cleaned tuple type */
746 if (operation == CMD_SELECT)
747 tupType = j->jf_cleanTupType;
751 estate->es_junkFilter = NULL;
755 * If doing SELECT INTO, initialize the "into" relation. We must wait
756 * till now so we have the "clean" result tuple type to create the new
759 * If EXPLAIN, skip creating the "into" relation.
761 intoRelationDesc = (Relation) NULL;
763 if (do_select_into && !explainOnly)
772 * find namespace to create in, check permissions
774 intoName = parseTree->into->relname;
775 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
777 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
779 if (aclresult != ACLCHECK_OK)
780 aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
781 get_namespace_name(namespaceId));
784 * have to copy tupType to get rid of constraints
786 tupdesc = CreateTupleDescCopy(tupType);
788 intoRelationId = heap_create_with_catalog(intoName,
794 allowSystemTableMods);
796 FreeTupleDesc(tupdesc);
799 * Advance command counter so that the newly-created relation's
800 * catalog tuples will be visible to heap_open.
802 CommandCounterIncrement();
805 * If necessary, create a TOAST table for the into relation. Note
806 * that AlterTableCreateToastTable ends with
807 * CommandCounterIncrement(), so that the TOAST table will be
808 * visible for insertion.
810 AlterTableCreateToastTable(intoRelationId, true);
813 * And open the constructed table for writing.
815 intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock);
818 estate->es_into_relation_descriptor = intoRelationDesc;
820 queryDesc->tupDesc = tupType;
821 queryDesc->planstate = planstate;
825 * Initialize ResultRelInfo data for one result relation
828 initResultRelInfo(ResultRelInfo *resultRelInfo,
829 Index resultRelationIndex,
833 Oid resultRelationOid;
834 Relation resultRelationDesc;
836 resultRelationOid = getrelid(resultRelationIndex, rangeTable);
837 resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
839 switch (resultRelationDesc->rd_rel->relkind)
841 case RELKIND_SEQUENCE:
843 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
844 errmsg("cannot change sequence relation \"%s\"",
845 RelationGetRelationName(resultRelationDesc))));
847 case RELKIND_TOASTVALUE:
849 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
850 errmsg("cannot change toast relation \"%s\"",
851 RelationGetRelationName(resultRelationDesc))));
855 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
856 errmsg("cannot change view relation \"%s\"",
857 RelationGetRelationName(resultRelationDesc))));
861 MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
862 resultRelInfo->type = T_ResultRelInfo;
863 resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
864 resultRelInfo->ri_RelationDesc = resultRelationDesc;
865 resultRelInfo->ri_NumIndices = 0;
866 resultRelInfo->ri_IndexRelationDescs = NULL;
867 resultRelInfo->ri_IndexRelationInfo = NULL;
868 /* make a copy so as not to depend on relcache info not changing... */
869 resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
870 resultRelInfo->ri_TrigFunctions = NULL;
871 resultRelInfo->ri_ConstraintExprs = NULL;
872 resultRelInfo->ri_junkFilter = NULL;
875 * If there are indices on the result relation, open them and save
876 * descriptors in the result relation info, so that we can add new
877 * index entries for the tuples we add/update. We need not do this
878 * for a DELETE, however, since deletion doesn't affect indexes.
880 if (resultRelationDesc->rd_rel->relhasindex &&
881 operation != CMD_DELETE)
882 ExecOpenIndices(resultRelInfo);
885 /* ----------------------------------------------------------------
888 * Cleans up the query plan -- closes files and frees up storage
890 * NOTE: we are no longer very worried about freeing storage per se
891 * in this code; FreeExecutorState should be guaranteed to release all
892 * memory that needs to be released. What we are worried about doing
893 * is closing relations and dropping buffer pins. Thus, for example,
894 * tuple tables must be cleared or dropped to ensure pins are released.
895 * ----------------------------------------------------------------
898 ExecEndPlan(PlanState * planstate, EState *estate)
900 ResultRelInfo *resultRelInfo;
905 * shut down any PlanQual processing we were doing
907 if (estate->es_evalPlanQual != NULL)
908 EndEvalPlanQual(estate);
911 * shut down the node-type-specific query processing
913 ExecEndNode(planstate);
916 * destroy the executor "tuple" table.
918 ExecDropTupleTable(estate->es_tupleTable, true);
919 estate->es_tupleTable = NULL;
922 * close the result relation(s) if any, but hold locks until xact
925 resultRelInfo = estate->es_result_relations;
926 for (i = estate->es_num_result_relations; i > 0; i--)
928 /* Close indices and then the relation itself */
929 ExecCloseIndices(resultRelInfo);
930 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
935 * close the "into" relation if necessary, again keeping lock
937 if (estate->es_into_relation_descriptor != NULL)
938 heap_close(estate->es_into_relation_descriptor, NoLock);
941 * close any relations selected FOR UPDATE, again keeping locks
943 foreach(l, estate->es_rowMark)
945 execRowMark *erm = lfirst(l);
947 heap_close(erm->relation, NoLock);
951 /* ----------------------------------------------------------------
954 * processes the query plan to retrieve 'numberTuples' tuples in the
955 * direction specified.
957 * Retrieves all tuples if numberTuples is 0
959 * result is either a slot containing the last tuple in the case
960 * of a SELECT or NULL otherwise.
962 * Note: the ctid attribute is a 'junk' attribute that is removed before the
964 * ----------------------------------------------------------------
966 static TupleTableSlot *
967 ExecutePlan(EState *estate,
968 PlanState * planstate,
971 ScanDirection direction,
974 JunkFilter *junkfilter;
975 TupleTableSlot *slot;
976 ItemPointer tupleid = NULL;
977 ItemPointerData tuple_ctid;
978 long current_tuple_count;
979 TupleTableSlot *result;
982 * initialize local variables
985 current_tuple_count = 0;
991 estate->es_direction = direction;
994 * Process BEFORE EACH STATEMENT triggers
999 ExecBSUpdateTriggers(estate, estate->es_result_relation_info);
1002 ExecBSDeleteTriggers(estate, estate->es_result_relation_info);
1005 ExecBSInsertTriggers(estate, estate->es_result_relation_info);
1013 * Loop until we've processed the proper number of tuples from the
1019 /* Reset the per-output-tuple exprcontext */
1020 ResetPerTupleExprContext(estate);
1023 * Execute the plan and obtain a tuple
1026 if (estate->es_useEvalPlan)
1028 slot = EvalPlanQualNext(estate);
1029 if (TupIsNull(slot))
1030 slot = ExecProcNode(planstate);
1033 slot = ExecProcNode(planstate);
1036 * if the tuple is null, then we assume there is nothing more to
1037 * process so we just return null...
1039 if (TupIsNull(slot))
1046 * if we have a junk filter, then project a new tuple with the
1049 * Store this new "clean" tuple in the junkfilter's resultSlot.
1050 * (Formerly, we stored it back over the "dirty" tuple, which is
1051 * WRONG because that tuple slot has the wrong descriptor.)
1053 * Also, extract all the junk information we need.
1055 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
1062 * extract the 'ctid' junk attribute.
1064 if (operation == CMD_UPDATE || operation == CMD_DELETE)
1066 if (!ExecGetJunkAttribute(junkfilter,
1071 elog(ERROR, "could not find junk ctid column");
1073 /* shouldn't ever get a null result... */
1075 elog(ERROR, "ctid is NULL");
1077 tupleid = (ItemPointer) DatumGetPointer(datum);
1078 tuple_ctid = *tupleid; /* make sure we don't free the
1080 tupleid = &tuple_ctid;
1082 else if (estate->es_rowMark != NIL)
1087 foreach(l, estate->es_rowMark)
1089 execRowMark *erm = lfirst(l);
1091 HeapTupleData tuple;
1092 TupleTableSlot *newSlot;
1095 if (!ExecGetJunkAttribute(junkfilter,
1100 elog(ERROR, "could not find junk \"%s\" column",
1103 /* shouldn't ever get a null result... */
1105 elog(ERROR, "\"%s\" is NULL", erm->resname);
1107 tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1108 test = heap_mark4update(erm->relation, &tuple, &buffer,
1109 estate->es_snapshot->curcid);
1110 ReleaseBuffer(buffer);
1113 case HeapTupleSelfUpdated:
1114 /* treat it as deleted; do not process */
1117 case HeapTupleMayBeUpdated:
1120 case HeapTupleUpdated:
1121 if (XactIsoLevel == XACT_SERIALIZABLE)
1123 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1124 errmsg("could not serialize access due to concurrent update")));
1125 if (!(ItemPointerEquals(&(tuple.t_self),
1126 (ItemPointer) DatumGetPointer(datum))))
1128 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1129 if (!(TupIsNull(newSlot)))
1132 estate->es_useEvalPlan = true;
1138 * if tuple was deleted or PlanQual failed for
1139 * updated tuple - we must not return this
1145 elog(ERROR, "unrecognized heap_mark4update status: %u",
1153 * Finally create a new "clean" tuple with all junk attributes
1156 newTuple = ExecRemoveJunk(junkfilter, slot);
1158 slot = ExecStoreTuple(newTuple, /* tuple to store */
1159 junkfilter->jf_resultSlot, /* dest slot */
1160 InvalidBuffer, /* this tuple has no
1162 true); /* tuple should be pfreed */
1166 * now that we have a tuple, do the appropriate thing with it..
1167 * either return it to the user, add it to a relation someplace,
1168 * delete it from a relation, or modify some of its attributes.
1173 ExecSelect(slot, /* slot containing tuple */
1174 dest, /* destination's tuple-receiver obj */
1180 ExecInsert(slot, tupleid, estate);
1185 ExecDelete(slot, tupleid, estate);
1190 ExecUpdate(slot, tupleid, estate);
1195 elog(ERROR, "unrecognized operation code: %d",
1202 * check our tuple count.. if we've processed the proper number
1203 * then quit, else loop again and process more tuples. Zero
1204 * numberTuples means no limit.
1206 current_tuple_count++;
1207 if (numberTuples && numberTuples == current_tuple_count)
1212 * Process AFTER EACH STATEMENT triggers
1217 ExecASUpdateTriggers(estate, estate->es_result_relation_info);
1220 ExecASDeleteTriggers(estate, estate->es_result_relation_info);
1223 ExecASInsertTriggers(estate, estate->es_result_relation_info);
1231 * here, result is either a slot containing a tuple in the case of a
1232 * SELECT or NULL otherwise.
1237 /* ----------------------------------------------------------------
1240 * SELECTs are easy.. we just pass the tuple to the appropriate
1241 * print function. The only complexity is when we do a
1242 * "SELECT INTO", in which case we insert the tuple into
1243 * the appropriate relation (note: this is a newly created relation
1244 * so we don't need to worry about indices or locks.)
1245 * ----------------------------------------------------------------
1248 ExecSelect(TupleTableSlot *slot,
1256 * get the heap tuple out of the tuple table slot
1259 attrtype = slot->ttc_tupleDescriptor;
1262 * insert the tuple into the "into relation"
1264 * XXX this probably ought to be replaced by a separate destination
1266 if (estate->es_into_relation_descriptor != NULL)
1268 heap_insert(estate->es_into_relation_descriptor, tuple,
1269 estate->es_snapshot->curcid);
1274 * send the tuple to the destination
1276 (*dest->receiveTuple) (tuple, attrtype, dest);
1278 (estate->es_processed)++;
1281 /* ----------------------------------------------------------------
1284 * INSERTs are trickier.. we have to insert the tuple into
1285 * the base relation and insert appropriate tuples into the
1287 * ----------------------------------------------------------------
1290 ExecInsert(TupleTableSlot *slot,
1291 ItemPointer tupleid,
1295 ResultRelInfo *resultRelInfo;
1296 Relation resultRelationDesc;
1301 * get the heap tuple out of the tuple table slot
1306 * get information on the (current) result relation
1308 resultRelInfo = estate->es_result_relation_info;
1309 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1311 /* BEFORE ROW INSERT Triggers */
1312 if (resultRelInfo->ri_TrigDesc &&
1313 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1317 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1319 if (newtuple == NULL) /* "do nothing" */
1322 if (newtuple != tuple) /* modified by Trigger(s) */
1325 * Insert modified tuple into tuple table slot, replacing the
1326 * original. We assume that it was allocated in per-tuple
1327 * memory context, and therefore will go away by itself. The
1328 * tuple table slot should not try to clear it.
1330 ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1336 * Check the constraints of the tuple
1338 if (resultRelationDesc->rd_att->constr)
1339 ExecConstraints(resultRelInfo, slot, estate);
1344 newId = heap_insert(resultRelationDesc, tuple,
1345 estate->es_snapshot->curcid);
1348 (estate->es_processed)++;
1349 estate->es_lastoid = newId;
1350 setLastTid(&(tuple->t_self));
1355 * Note: heap_insert adds a new tuple to a relation. As a side effect,
1356 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1359 numIndices = resultRelInfo->ri_NumIndices;
1361 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1363 /* AFTER ROW INSERT Triggers */
1364 ExecARInsertTriggers(estate, resultRelInfo, tuple);
1367 /* ----------------------------------------------------------------
1370 * DELETE is like UPDATE, we delete the tuple and its
1372 * ----------------------------------------------------------------
1375 ExecDelete(TupleTableSlot *slot,
1376 ItemPointer tupleid,
1379 ResultRelInfo *resultRelInfo;
1380 Relation resultRelationDesc;
1381 ItemPointerData ctid;
1385 * get information on the (current) result relation
1387 resultRelInfo = estate->es_result_relation_info;
1388 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1390 /* BEFORE ROW DELETE Triggers */
1391 if (resultRelInfo->ri_TrigDesc &&
1392 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1396 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid,
1397 estate->es_snapshot->curcid);
1399 if (!dodelete) /* "do nothing" */
1407 result = heap_delete(resultRelationDesc, tupleid,
1409 estate->es_snapshot->curcid);
1412 case HeapTupleSelfUpdated:
1413 /* already deleted by self; nothing to do */
1416 case HeapTupleMayBeUpdated:
1419 case HeapTupleUpdated:
1420 if (XactIsoLevel == XACT_SERIALIZABLE)
1422 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1423 errmsg("could not serialize access due to concurrent update")));
1424 else if (!(ItemPointerEquals(tupleid, &ctid)))
1426 TupleTableSlot *epqslot = EvalPlanQual(estate,
1427 resultRelInfo->ri_RangeTableIndex, &ctid);
1429 if (!TupIsNull(epqslot))
1435 /* tuple already deleted; nothing to do */
1439 elog(ERROR, "unrecognized heap_delete status: %u", result);
1444 (estate->es_processed)++;
1447 * Note: Normally one would think that we have to delete index tuples
1448 * associated with the heap tuple now..
1450 * ... but in POSTGRES, we have no need to do this because the vacuum
1451 * daemon automatically opens an index scan and deletes index tuples
1452 * when it finds deleted heap tuples. -cim 9/27/89
1455 /* AFTER ROW DELETE Triggers */
1456 ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1459 /* ----------------------------------------------------------------
1462 * note: we can't run UPDATE queries with transactions
1463 * off because UPDATEs are actually INSERTs and our
1464 * scan will mistakenly loop forever, updating the tuple
1465 * it just inserted.. This should be fixed but until it
1466 * is, we don't want to get stuck in an infinite loop
1467 * which corrupts your database..
1468 * ----------------------------------------------------------------
1471 ExecUpdate(TupleTableSlot *slot,
1472 ItemPointer tupleid,
1476 ResultRelInfo *resultRelInfo;
1477 Relation resultRelationDesc;
1478 ItemPointerData ctid;
1483 * abort the operation if not running transactions
1485 if (IsBootstrapProcessingMode())
1486 elog(ERROR, "cannot UPDATE during bootstrap");
1489 * get the heap tuple out of the tuple table slot
1494 * get information on the (current) result relation
1496 resultRelInfo = estate->es_result_relation_info;
1497 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1499 /* BEFORE ROW UPDATE Triggers */
1500 if (resultRelInfo->ri_TrigDesc &&
1501 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1505 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1507 estate->es_snapshot->curcid);
1509 if (newtuple == NULL) /* "do nothing" */
1512 if (newtuple != tuple) /* modified by Trigger(s) */
1515 * Insert modified tuple into tuple table slot, replacing the
1516 * original. We assume that it was allocated in per-tuple
1517 * memory context, and therefore will go away by itself. The
1518 * tuple table slot should not try to clear it.
1520 ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1526 * Check the constraints of the tuple
1528 * If we generate a new candidate tuple after EvalPlanQual testing, we
1529 * must loop back here and recheck constraints. (We don't need to
1530 * redo triggers, however. If there are any BEFORE triggers then
1531 * trigger.c will have done mark4update to lock the correct tuple, so
1532 * there's no need to do them again.)
1535 if (resultRelationDesc->rd_att->constr)
1536 ExecConstraints(resultRelInfo, slot, estate);
1539 * replace the heap tuple
1541 result = heap_update(resultRelationDesc, tupleid, tuple,
1543 estate->es_snapshot->curcid);
1546 case HeapTupleSelfUpdated:
1547 /* already deleted by self; nothing to do */
1550 case HeapTupleMayBeUpdated:
1553 case HeapTupleUpdated:
1554 if (XactIsoLevel == XACT_SERIALIZABLE)
1556 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1557 errmsg("could not serialize access due to concurrent update")));
1558 else if (!(ItemPointerEquals(tupleid, &ctid)))
1560 TupleTableSlot *epqslot = EvalPlanQual(estate,
1561 resultRelInfo->ri_RangeTableIndex, &ctid);
1563 if (!TupIsNull(epqslot))
1566 tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1567 slot = ExecStoreTuple(tuple,
1568 estate->es_junkFilter->jf_resultSlot,
1569 InvalidBuffer, true);
1573 /* tuple already deleted; nothing to do */
1577 elog(ERROR, "unrecognized heap_update status: %u", result);
1582 (estate->es_processed)++;
1585 * Note: instead of having to update the old index tuples associated
1586 * with the heap tuple, all we do is form and insert new index tuples.
1587 * This is because UPDATEs are actually DELETEs and INSERTs and index
1588 * tuple deletion is done automagically by the vacuum daemon. All we
1589 * do is insert new index tuples. -cim 9/27/89
1595 * heap_update updates a tuple in the base relation by invalidating it
1596 * and then inserting a new tuple to the relation. As a side effect,
1597 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1598 * field. So we now insert index tuples using the new tupleid stored
1602 numIndices = resultRelInfo->ri_NumIndices;
1604 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1606 /* AFTER ROW UPDATE Triggers */
1607 ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1611 ExecRelCheck(ResultRelInfo *resultRelInfo,
1612 TupleTableSlot *slot, EState *estate)
1614 Relation rel = resultRelInfo->ri_RelationDesc;
1615 int ncheck = rel->rd_att->constr->num_check;
1616 ConstrCheck *check = rel->rd_att->constr->check;
1617 ExprContext *econtext;
1618 MemoryContext oldContext;
1623 * If first time through for this result relation, build expression
1624 * nodetrees for rel's constraint expressions. Keep them in the
1625 * per-query memory context so they'll survive throughout the query.
1627 if (resultRelInfo->ri_ConstraintExprs == NULL)
1629 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1630 resultRelInfo->ri_ConstraintExprs =
1631 (List **) palloc(ncheck * sizeof(List *));
1632 for (i = 0; i < ncheck; i++)
1634 qual = (List *) stringToNode(check[i].ccbin);
1635 resultRelInfo->ri_ConstraintExprs[i] = (List *)
1636 ExecPrepareExpr((Expr *) qual, estate);
1638 MemoryContextSwitchTo(oldContext);
1642 * We will use the EState's per-tuple context for evaluating
1643 * constraint expressions (creating it if it's not already there).
1645 econtext = GetPerTupleExprContext(estate);
1647 /* Arrange for econtext's scan tuple to be the tuple under test */
1648 econtext->ecxt_scantuple = slot;
1650 /* And evaluate the constraints */
1651 for (i = 0; i < ncheck; i++)
1653 qual = resultRelInfo->ri_ConstraintExprs[i];
1656 * NOTE: SQL92 specifies that a NULL result from a constraint
1657 * expression is not to be treated as a failure. Therefore, tell
1658 * ExecQual to return TRUE for NULL.
1660 if (!ExecQual(qual, econtext, true))
1661 return check[i].ccname;
1664 /* NULL result means no error */
1669 ExecConstraints(ResultRelInfo *resultRelInfo,
1670 TupleTableSlot *slot, EState *estate)
1672 Relation rel = resultRelInfo->ri_RelationDesc;
1673 HeapTuple tuple = slot->val;
1674 TupleConstr *constr = rel->rd_att->constr;
1678 if (constr->has_not_null)
1680 int natts = rel->rd_att->natts;
1683 for (attrChk = 1; attrChk <= natts; attrChk++)
1685 if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1686 heap_attisnull(tuple, attrChk))
1688 (errcode(ERRCODE_NOT_NULL_VIOLATION),
1689 errmsg("null value for attribute \"%s\" violates NOT NULL constraint",
1690 NameStr(rel->rd_att->attrs[attrChk - 1]->attname))));
1694 if (constr->num_check > 0)
1698 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1700 (errcode(ERRCODE_CHECK_VIOLATION),
1701 errmsg("new row for relation \"%s\" violates CHECK constraint \"%s\"",
1702 RelationGetRelationName(rel), failed)));
1707 * Check a modified tuple to see if we want to process its updated version
1708 * under READ COMMITTED rules.
1710 * See backend/executor/README for some info about how this works.
1713 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1718 HeapTupleData tuple;
1719 HeapTuple copyTuple = NULL;
1725 * find relation containing target tuple
1727 if (estate->es_result_relation_info != NULL &&
1728 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1729 relation = estate->es_result_relation_info->ri_RelationDesc;
1735 foreach(l, estate->es_rowMark)
1737 if (((execRowMark *) lfirst(l))->rti == rti)
1739 relation = ((execRowMark *) lfirst(l))->relation;
1743 if (relation == NULL)
1744 elog(ERROR, "could not find RowMark for RT index %u", rti);
1750 * Loop here to deal with updated or busy tuples
1752 tuple.t_self = *tid;
1757 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1759 TransactionId xwait = SnapshotDirty->xmax;
1761 /* xmin should not be dirty... */
1762 if (TransactionIdIsValid(SnapshotDirty->xmin))
1763 elog(ERROR, "t_xmin is uncommitted in tuple to be updated");
1766 * If tuple is being updated by other transaction then we have
1767 * to wait for its commit/abort.
1769 if (TransactionIdIsValid(xwait))
1771 ReleaseBuffer(buffer);
1772 XactLockTableWait(xwait);
1777 * We got tuple - now copy it for use by recheck query.
1779 copyTuple = heap_copytuple(&tuple);
1780 ReleaseBuffer(buffer);
1785 * Oops! Invalid tuple. Have to check is it updated or deleted.
1786 * Note that it's possible to get invalid SnapshotDirty->tid if
1787 * tuple updated by this transaction. Have we to check this ?
1789 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1790 !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1792 /* updated, so look at the updated copy */
1793 tuple.t_self = SnapshotDirty->tid;
1798 * Deleted or updated by this transaction; forget it.
1804 * For UPDATE/DELETE we have to return tid of actual row we're
1807 *tid = tuple.t_self;
1810 * Need to run a recheck subquery. Find or create a PQ stack entry.
1812 epq = estate->es_evalPlanQual;
1815 if (epq != NULL && epq->rti == 0)
1817 /* Top PQ stack entry is idle, so re-use it */
1818 Assert(!(estate->es_useEvalPlan) && epq->next == NULL);
1824 * If this is request for another RTE - Ra, - then we have to check
1825 * wasn't PlanQual requested for Ra already and if so then Ra' row was
1826 * updated again and we have to re-start old execution for Ra and
1827 * forget all what we done after Ra was suspended. Cool? -:))
1829 if (epq != NULL && epq->rti != rti &&
1830 epq->estate->es_evTuple[rti - 1] != NULL)
1834 evalPlanQual *oldepq;
1836 /* stop execution */
1837 EvalPlanQualStop(epq);
1838 /* pop previous PlanQual from the stack */
1840 Assert(oldepq && oldepq->rti != 0);
1841 /* push current PQ to freePQ stack */
1844 estate->es_evalPlanQual = epq;
1845 } while (epq->rti != rti);
1849 * If we are requested for another RTE then we have to suspend
1850 * execution of current PlanQual and start execution for new one.
1852 if (epq == NULL || epq->rti != rti)
1854 /* try to reuse plan used previously */
1855 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1857 if (newepq == NULL) /* first call or freePQ stack is empty */
1859 newepq = (evalPlanQual *) palloc0(sizeof(evalPlanQual));
1860 newepq->free = NULL;
1861 newepq->estate = NULL;
1862 newepq->planstate = NULL;
1866 /* recycle previously used PlanQual */
1867 Assert(newepq->estate == NULL);
1870 /* push current PQ to the stack */
1873 estate->es_evalPlanQual = epq;
1878 Assert(epq->rti == rti);
1881 * Ok - we're requested for the same RTE. Unfortunately we still have
1882 * to end and restart execution of the plan, because ExecReScan
1883 * wouldn't ensure that upper plan nodes would reset themselves. We
1884 * could make that work if insertion of the target tuple were
1885 * integrated with the Param mechanism somehow, so that the upper plan
1886 * nodes know that their children's outputs have changed.
1888 * Note that the stack of free evalPlanQual nodes is quite useless at the
1889 * moment, since it only saves us from pallocing/releasing the
1890 * evalPlanQual nodes themselves. But it will be useful once we
1891 * implement ReScan instead of end/restart for re-using PlanQual
1896 /* stop execution */
1897 EvalPlanQualStop(epq);
1901 * Initialize new recheck query.
1903 * Note: if we were re-using PlanQual plans via ExecReScan, we'd need to
1904 * instead copy down changeable state from the top plan (including
1905 * es_result_relation_info, es_junkFilter) and reset locally
1906 * changeable state in the epq (including es_param_exec_vals,
1909 EvalPlanQualStart(epq, estate, epq->next);
1912 * free old RTE' tuple, if any, and store target tuple where
1913 * relation's scan node will see it
1915 epqstate = epq->estate;
1916 if (epqstate->es_evTuple[rti - 1] != NULL)
1917 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1918 epqstate->es_evTuple[rti - 1] = copyTuple;
1920 return EvalPlanQualNext(estate);
1923 static TupleTableSlot *
1924 EvalPlanQualNext(EState *estate)
1926 evalPlanQual *epq = estate->es_evalPlanQual;
1927 MemoryContext oldcontext;
1928 TupleTableSlot *slot;
1930 Assert(epq->rti != 0);
1933 oldcontext = MemoryContextSwitchTo(epq->estate->es_query_cxt);
1934 slot = ExecProcNode(epq->planstate);
1935 MemoryContextSwitchTo(oldcontext);
1938 * No more tuples for this PQ. Continue previous one.
1940 if (TupIsNull(slot))
1942 evalPlanQual *oldepq;
1944 /* stop execution */
1945 EvalPlanQualStop(epq);
1946 /* pop old PQ from the stack */
1950 /* this is the first (oldest) PQ - mark as free */
1952 estate->es_useEvalPlan = false;
1953 /* and continue Query execution */
1956 Assert(oldepq->rti != 0);
1957 /* push current PQ to freePQ stack */
1960 estate->es_evalPlanQual = epq;
1968 EndEvalPlanQual(EState *estate)
1970 evalPlanQual *epq = estate->es_evalPlanQual;
1972 if (epq->rti == 0) /* plans already shutdowned */
1974 Assert(epq->next == NULL);
1980 evalPlanQual *oldepq;
1982 /* stop execution */
1983 EvalPlanQualStop(epq);
1984 /* pop old PQ from the stack */
1988 /* this is the first (oldest) PQ - mark as free */
1990 estate->es_useEvalPlan = false;
1993 Assert(oldepq->rti != 0);
1994 /* push current PQ to freePQ stack */
1997 estate->es_evalPlanQual = epq;
2002 * Start execution of one level of PlanQual.
2004 * This is a cut-down version of ExecutorStart(): we copy some state from
2005 * the top-level estate rather than initializing it fresh.
2008 EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
2012 MemoryContext oldcontext;
2014 rtsize = length(estate->es_range_table);
2016 epq->estate = epqstate = CreateExecutorState();
2018 oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2021 * The epqstates share the top query's copy of unchanging state such
2022 * as the snapshot, rangetable, result-rel info, and external Param
2023 * info. They need their own copies of local state, including a tuple
2024 * table, es_param_exec_vals, etc.
2026 epqstate->es_direction = ForwardScanDirection;
2027 epqstate->es_snapshot = estate->es_snapshot;
2028 epqstate->es_range_table = estate->es_range_table;
2029 epqstate->es_result_relations = estate->es_result_relations;
2030 epqstate->es_num_result_relations = estate->es_num_result_relations;
2031 epqstate->es_result_relation_info = estate->es_result_relation_info;
2032 epqstate->es_junkFilter = estate->es_junkFilter;
2033 epqstate->es_into_relation_descriptor = estate->es_into_relation_descriptor;
2034 epqstate->es_param_list_info = estate->es_param_list_info;
2035 if (estate->es_topPlan->nParamExec > 0)
2036 epqstate->es_param_exec_vals = (ParamExecData *)
2037 palloc0(estate->es_topPlan->nParamExec * sizeof(ParamExecData));
2038 epqstate->es_rowMark = estate->es_rowMark;
2039 epqstate->es_instrument = estate->es_instrument;
2040 epqstate->es_force_oids = estate->es_force_oids;
2041 epqstate->es_topPlan = estate->es_topPlan;
2044 * Each epqstate must have its own es_evTupleNull state, but all the
2045 * stack entries share es_evTuple state. This allows sub-rechecks to
2046 * inherit the value being examined by an outer recheck.
2048 epqstate->es_evTupleNull = (bool *) palloc0(rtsize * sizeof(bool));
2049 if (priorepq == NULL)
2050 /* first PQ stack entry */
2051 epqstate->es_evTuple = (HeapTuple *)
2052 palloc0(rtsize * sizeof(HeapTuple));
2054 /* later stack entries share the same storage */
2055 epqstate->es_evTuple = priorepq->estate->es_evTuple;
2057 epqstate->es_tupleTable =
2058 ExecCreateTupleTable(estate->es_tupleTable->size);
2060 epq->planstate = ExecInitNode(estate->es_topPlan, epqstate);
2062 MemoryContextSwitchTo(oldcontext);
2066 * End execution of one level of PlanQual.
2068 * This is a cut-down version of ExecutorEnd(); basically we want to do most
2069 * of the normal cleanup, but *not* close result relations (which we are
2070 * just sharing from the outer query).
2073 EvalPlanQualStop(evalPlanQual *epq)
2075 EState *epqstate = epq->estate;
2076 MemoryContext oldcontext;
2078 oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2080 ExecEndNode(epq->planstate);
2082 ExecDropTupleTable(epqstate->es_tupleTable, true);
2083 epqstate->es_tupleTable = NULL;
2085 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
2087 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
2088 epqstate->es_evTuple[epq->rti - 1] = NULL;
2091 MemoryContextSwitchTo(oldcontext);
2093 FreeExecutorState(epqstate);
2096 epq->planstate = NULL;