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11 * The old ExecutorMain() has been replaced by ExecutorStart(),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 and the execution state is required
18 * ExecutorStart() must be called at the beginning of any execution of any
19 * query plan and ExecutorEnd() should always be called at the end of
20 * execution of a plan.
22 * ExecutorRun accepts direction and count arguments that specify whether
23 * the plan is to be executed forwards, backwards, and for how many tuples.
25 * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
26 * Portions Copyright (c) 1994, Regents of the University of California
30 * $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.184 2002/11/11 22:19:22 tgl Exp $
32 *-------------------------------------------------------------------------
36 #include "access/heapam.h"
37 #include "catalog/heap.h"
38 #include "catalog/namespace.h"
39 #include "commands/tablecmds.h"
40 #include "commands/trigger.h"
41 #include "executor/execdebug.h"
42 #include "executor/execdefs.h"
43 #include "miscadmin.h"
44 #include "optimizer/var.h"
45 #include "parser/parsetree.h"
46 #include "utils/acl.h"
47 #include "utils/lsyscache.h"
50 /* decls for local routines only used within this module */
51 static TupleDesc InitPlan(CmdType operation,
55 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
56 Index resultRelationIndex,
59 static void EndPlan(Plan *plan, EState *estate);
60 static TupleTableSlot *ExecutePlan(EState *estate, Plan *plan,
63 ScanDirection direction,
64 DestReceiver *destfunc);
65 static void ExecSelect(TupleTableSlot *slot,
66 DestReceiver *destfunc,
68 static void ExecInsert(TupleTableSlot *slot, ItemPointer tupleid,
70 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
72 static void ExecUpdate(TupleTableSlot *slot, ItemPointer tupleid,
74 static TupleTableSlot *EvalPlanQualNext(EState *estate);
75 static void EndEvalPlanQual(EState *estate);
76 static void ExecCheckQueryPerms(CmdType operation, Query *parseTree,
78 static void ExecCheckPlanPerms(Plan *plan, List *rangeTable,
80 static void ExecCheckRTPerms(List *rangeTable, CmdType operation);
81 static void ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation);
83 /* end of local decls */
86 /* ----------------------------------------------------------------
89 * This routine must be called at the beginning of any execution of any
92 * returns a TupleDesc which describes the attributes of the tuples to
93 * be returned by the query. (Same value is saved in queryDesc)
95 * NB: the CurrentMemoryContext when this is called must be the context
96 * to be used as the per-query context for the query plan. ExecutorRun()
97 * and ExecutorEnd() must be called in this same memory context.
98 * ----------------------------------------------------------------
101 ExecutorStart(QueryDesc *queryDesc, EState *estate)
106 Assert(queryDesc != NULL);
108 if (queryDesc->plantree->nParamExec > 0)
110 estate->es_param_exec_vals = (ParamExecData *)
111 palloc(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
112 MemSet(estate->es_param_exec_vals, 0,
113 queryDesc->plantree->nParamExec * sizeof(ParamExecData));
117 * Make our own private copy of the current query snapshot data.
119 * This "freezes" our idea of which tuples are good and which are not for
120 * the life of this query, even if it outlives the current command and
123 estate->es_snapshot = CopyQuerySnapshot();
126 * Initialize the plan
128 result = InitPlan(queryDesc->operation,
129 queryDesc->parsetree,
133 queryDesc->tupDesc = result;
138 /* ----------------------------------------------------------------
141 * This is the main routine of the executor module. It accepts
142 * the query descriptor from the traffic cop and executes the
145 * ExecutorStart must have been called already.
147 * If direction is NoMovementScanDirection then nothing is done
148 * except to start up/shut down the destination. Otherwise,
149 * we retrieve up to 'count' tuples in the specified direction.
151 * Note: count = 0 is interpreted as no portal limit, e.g. run to
154 * ----------------------------------------------------------------
157 ExecutorRun(QueryDesc *queryDesc, EState *estate,
158 ScanDirection direction, long count)
163 DestReceiver *destfunc;
164 TupleTableSlot *result;
169 Assert(queryDesc != NULL);
172 * extract information from the query descriptor and the query
175 operation = queryDesc->operation;
176 plan = queryDesc->plantree;
177 dest = queryDesc->dest;
180 * startup tuple receiver
182 estate->es_processed = 0;
183 estate->es_lastoid = InvalidOid;
185 destfunc = DestToFunction(dest);
186 (*destfunc->setup) (destfunc, (int) operation,
187 queryDesc->portalName, queryDesc->tupDesc);
192 if (direction == NoMovementScanDirection)
195 result = ExecutePlan(estate,
205 (*destfunc->cleanup) (destfunc);
210 /* ----------------------------------------------------------------
213 * This routine must be called at the end of execution of any
215 * ----------------------------------------------------------------
218 ExecutorEnd(QueryDesc *queryDesc, EState *estate)
221 Assert(queryDesc != NULL);
223 EndPlan(queryDesc->plantree, estate);
225 if (estate->es_snapshot != NULL)
227 if (estate->es_snapshot->xcnt > 0)
228 pfree(estate->es_snapshot->xip);
229 pfree(estate->es_snapshot);
230 estate->es_snapshot = NULL;
233 if (estate->es_param_exec_vals != NULL)
235 pfree(estate->es_param_exec_vals);
236 estate->es_param_exec_vals = NULL;
242 * ExecCheckQueryPerms
243 * Check access permissions for all relations referenced in a query.
246 ExecCheckQueryPerms(CmdType operation, Query *parseTree, Plan *plan)
249 * Check RTEs in the query's primary rangetable.
251 ExecCheckRTPerms(parseTree->rtable, operation);
254 * Search for subplans and APPEND nodes to check their rangetables.
256 ExecCheckPlanPerms(plan, parseTree->rtable, operation);
261 * Recursively scan the plan tree to check access permissions in
265 ExecCheckPlanPerms(Plan *plan, List *rangeTable, CmdType operation)
272 /* Check subplans, which we assume are plain SELECT queries */
274 foreach(subp, plan->initPlan)
276 SubPlan *subplan = (SubPlan *) lfirst(subp);
278 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
279 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
281 foreach(subp, plan->subPlan)
283 SubPlan *subplan = (SubPlan *) lfirst(subp);
285 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
286 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
289 /* Check lower plan nodes */
291 ExecCheckPlanPerms(plan->lefttree, rangeTable, operation);
292 ExecCheckPlanPerms(plan->righttree, rangeTable, operation);
294 /* Do node-type-specific checks */
296 switch (nodeTag(plan))
300 SubqueryScan *scan = (SubqueryScan *) plan;
303 /* Recursively check the subquery */
304 rte = rt_fetch(scan->scan.scanrelid, rangeTable);
305 Assert(rte->rtekind == RTE_SUBQUERY);
306 ExecCheckQueryPerms(operation, rte->subquery, scan->subplan);
311 Append *app = (Append *) plan;
314 foreach(appendplans, app->appendplans)
316 ExecCheckPlanPerms((Plan *) lfirst(appendplans),
330 * Check access permissions for all relations listed in a range table.
333 ExecCheckRTPerms(List *rangeTable, CmdType operation)
337 foreach(lp, rangeTable)
339 RangeTblEntry *rte = lfirst(lp);
341 ExecCheckRTEPerms(rte, operation);
347 * Check access permissions for a single RTE.
350 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
354 AclResult aclcheck_result;
357 * Only plain-relation RTEs need to be checked here. Subquery RTEs
358 * will be checked when ExecCheckPlanPerms finds the SubqueryScan
359 * node, and function RTEs are checked by init_fcache when the
360 * function is prepared for execution. Join and special RTEs need no
363 if (rte->rtekind != RTE_RELATION)
369 * userid to check as: current user unless we have a setuid
372 * Note: GetUserId() is presently fast enough that there's no harm in
373 * calling it separately for each RTE. If that stops being true, we
374 * could call it once in ExecCheckQueryPerms and pass the userid down
375 * from there. But for now, no need for the extra clutter.
377 userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
379 #define CHECK(MODE) pg_class_aclcheck(relOid, userid, MODE)
381 if (rte->checkForRead)
383 aclcheck_result = CHECK(ACL_SELECT);
384 if (aclcheck_result != ACLCHECK_OK)
385 aclcheck_error(aclcheck_result, get_rel_name(relOid));
388 if (rte->checkForWrite)
391 * Note: write access in a SELECT context means SELECT FOR UPDATE.
392 * Right now we don't distinguish that from true update as far as
393 * permissions checks are concerned.
398 aclcheck_result = CHECK(ACL_INSERT);
402 aclcheck_result = CHECK(ACL_UPDATE);
405 aclcheck_result = CHECK(ACL_DELETE);
408 elog(ERROR, "ExecCheckRTEPerms: bogus operation %d",
410 aclcheck_result = ACLCHECK_OK; /* keep compiler quiet */
413 if (aclcheck_result != ACLCHECK_OK)
414 aclcheck_error(aclcheck_result, get_rel_name(relOid));
419 /* ===============================================================
420 * ===============================================================
421 static routines follow
422 * ===============================================================
423 * ===============================================================
426 typedef struct execRowMark
433 typedef struct evalPlanQual
438 struct evalPlanQual *free;
441 /* ----------------------------------------------------------------
444 * Initializes the query plan: open files, allocate storage
445 * and start up the rule manager
446 * ----------------------------------------------------------------
449 InitPlan(CmdType operation, Query *parseTree, Plan *plan, EState *estate)
452 Relation intoRelationDesc;
456 * Do permissions checks.
458 ExecCheckQueryPerms(operation, parseTree, plan);
461 * get information from query descriptor
463 rangeTable = parseTree->rtable;
466 * initialize the node's execution state
468 estate->es_range_table = rangeTable;
471 * if there is a result relation, initialize result relation stuff
473 if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
475 List *resultRelations = parseTree->resultRelations;
476 int numResultRelations;
477 ResultRelInfo *resultRelInfos;
479 if (resultRelations != NIL)
482 * Multiple result relations (due to inheritance)
483 * parseTree->resultRelations identifies them all
485 ResultRelInfo *resultRelInfo;
487 numResultRelations = length(resultRelations);
488 resultRelInfos = (ResultRelInfo *)
489 palloc(numResultRelations * sizeof(ResultRelInfo));
490 resultRelInfo = resultRelInfos;
491 while (resultRelations != NIL)
493 initResultRelInfo(resultRelInfo,
494 lfirsti(resultRelations),
498 resultRelations = lnext(resultRelations);
504 * Single result relation identified by
505 * parseTree->resultRelation
507 numResultRelations = 1;
508 resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
509 initResultRelInfo(resultRelInfos,
510 parseTree->resultRelation,
515 estate->es_result_relations = resultRelInfos;
516 estate->es_num_result_relations = numResultRelations;
517 /* Initialize to first or only result rel */
518 estate->es_result_relation_info = resultRelInfos;
523 * if no result relation, then set state appropriately
525 estate->es_result_relations = NULL;
526 estate->es_num_result_relations = 0;
527 estate->es_result_relation_info = NULL;
531 * Have to lock relations selected for update
533 estate->es_rowMark = NIL;
534 if (parseTree->rowMarks != NIL)
538 foreach(l, parseTree->rowMarks)
540 Index rti = lfirsti(l);
541 Oid relid = getrelid(rti, rangeTable);
545 relation = heap_open(relid, RowShareLock);
546 erm = (execRowMark *) palloc(sizeof(execRowMark));
547 erm->relation = relation;
549 snprintf(erm->resname, 32, "ctid%u", rti);
550 estate->es_rowMark = lappend(estate->es_rowMark, erm);
555 * initialize the executor "tuple" table. We need slots for all the
556 * plan nodes, plus possibly output slots for the junkfilter(s). At
557 * this point we aren't sure if we need junkfilters, so just add slots
558 * for them unconditionally.
561 int nSlots = ExecCountSlotsNode(plan);
563 if (parseTree->resultRelations != NIL)
564 nSlots += length(parseTree->resultRelations);
567 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
570 /* mark EvalPlanQual not active */
571 estate->es_origPlan = plan;
572 estate->es_evalPlanQual = NULL;
573 estate->es_evTuple = NULL;
574 estate->es_evTupleNull = NULL;
575 estate->es_useEvalPlan = false;
578 * initialize the private state information for all the nodes in the
579 * query tree. This opens files, allocates storage and leaves us
580 * ready to start processing tuples.
582 ExecInitNode(plan, estate, NULL);
585 * Get the tuple descriptor describing the type of tuples to return.
586 * (this is especially important if we are creating a relation with
589 tupType = ExecGetTupType(plan); /* tuple descriptor */
592 * Initialize the junk filter if needed. SELECT and INSERT queries
593 * need a filter if there are any junk attrs in the tlist. UPDATE and
594 * DELETE always need one, since there's always a junk 'ctid'
595 * attribute present --- no need to look first.
598 bool junk_filter_needed = false;
605 foreach(tlist, plan->targetlist)
607 TargetEntry *tle = (TargetEntry *) lfirst(tlist);
609 if (tle->resdom->resjunk)
611 junk_filter_needed = true;
618 junk_filter_needed = true;
624 if (junk_filter_needed)
627 * If there are multiple result relations, each one needs its
628 * own junk filter. Note this is only possible for
629 * UPDATE/DELETE, so we can't be fooled by some needing a
630 * filter and some not.
632 if (parseTree->resultRelations != NIL)
635 ResultRelInfo *resultRelInfo;
637 /* Top plan had better be an Append here. */
638 Assert(IsA(plan, Append));
639 Assert(((Append *) plan)->isTarget);
640 subplans = ((Append *) plan)->appendplans;
641 Assert(length(subplans) == estate->es_num_result_relations);
642 resultRelInfo = estate->es_result_relations;
643 while (subplans != NIL)
645 Plan *subplan = (Plan *) lfirst(subplans);
648 j = ExecInitJunkFilter(subplan->targetlist,
649 ExecGetTupType(subplan),
650 ExecAllocTableSlot(estate->es_tupleTable));
651 resultRelInfo->ri_junkFilter = j;
653 subplans = lnext(subplans);
657 * Set active junkfilter too; at this point ExecInitAppend
658 * has already selected an active result relation...
660 estate->es_junkFilter =
661 estate->es_result_relation_info->ri_junkFilter;
665 /* Normal case with just one JunkFilter */
668 j = ExecInitJunkFilter(plan->targetlist,
670 ExecAllocTableSlot(estate->es_tupleTable));
671 estate->es_junkFilter = j;
672 if (estate->es_result_relation_info)
673 estate->es_result_relation_info->ri_junkFilter = j;
675 /* For SELECT, want to return the cleaned tuple type */
676 if (operation == CMD_SELECT)
677 tupType = j->jf_cleanTupType;
681 estate->es_junkFilter = NULL;
685 * initialize the "into" relation
687 intoRelationDesc = (Relation) NULL;
689 if (operation == CMD_SELECT)
691 if (!parseTree->isPortal)
694 * a select into table --- need to create the "into" table
696 if (parseTree->into != NULL)
705 * find namespace to create in, check permissions
707 intoName = parseTree->into->relname;
708 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
710 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
712 if (aclresult != ACLCHECK_OK)
713 aclcheck_error(aclresult,
714 get_namespace_name(namespaceId));
717 * have to copy tupType to get rid of constraints
719 tupdesc = CreateTupleDescCopy(tupType);
722 * Formerly we forced the output table to have OIDs, but
723 * as of 7.3 it will not have OIDs, because it's too late
724 * here to change the tupdescs of the already-initialized
725 * plan tree. (Perhaps we could recurse and change them
726 * all, but it's not really worth the trouble IMHO...)
730 heap_create_with_catalog(intoName,
736 allowSystemTableMods);
738 FreeTupleDesc(tupdesc);
741 * Advance command counter so that the newly-created
742 * relation's catalog tuples will be visible to heap_open.
744 CommandCounterIncrement();
747 * If necessary, create a TOAST table for the into
748 * relation. Note that AlterTableCreateToastTable ends
749 * with CommandCounterIncrement(), so that the TOAST table
750 * will be visible for insertion.
752 AlterTableCreateToastTable(intoRelationId, true);
754 intoRelationDesc = heap_open(intoRelationId,
755 AccessExclusiveLock);
760 estate->es_into_relation_descriptor = intoRelationDesc;
766 * Initialize ResultRelInfo data for one result relation
769 initResultRelInfo(ResultRelInfo *resultRelInfo,
770 Index resultRelationIndex,
774 Oid resultRelationOid;
775 Relation resultRelationDesc;
777 resultRelationOid = getrelid(resultRelationIndex, rangeTable);
778 resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
780 switch (resultRelationDesc->rd_rel->relkind)
782 case RELKIND_SEQUENCE:
783 elog(ERROR, "You can't change sequence relation %s",
784 RelationGetRelationName(resultRelationDesc));
786 case RELKIND_TOASTVALUE:
787 elog(ERROR, "You can't change toast relation %s",
788 RelationGetRelationName(resultRelationDesc));
791 elog(ERROR, "You can't change view relation %s",
792 RelationGetRelationName(resultRelationDesc));
796 MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
797 resultRelInfo->type = T_ResultRelInfo;
798 resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
799 resultRelInfo->ri_RelationDesc = resultRelationDesc;
800 resultRelInfo->ri_NumIndices = 0;
801 resultRelInfo->ri_IndexRelationDescs = NULL;
802 resultRelInfo->ri_IndexRelationInfo = NULL;
803 /* make a copy so as not to depend on relcache info not changing... */
804 resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
805 resultRelInfo->ri_TrigFunctions = NULL;
806 resultRelInfo->ri_ConstraintExprs = NULL;
807 resultRelInfo->ri_junkFilter = NULL;
810 * If there are indices on the result relation, open them and save
811 * descriptors in the result relation info, so that we can add new
812 * index entries for the tuples we add/update. We need not do this
813 * for a DELETE, however, since deletion doesn't affect indexes.
815 if (resultRelationDesc->rd_rel->relhasindex &&
816 operation != CMD_DELETE)
817 ExecOpenIndices(resultRelInfo);
820 /* ----------------------------------------------------------------
823 * Cleans up the query plan -- closes files and free up storages
824 * ----------------------------------------------------------------
827 EndPlan(Plan *plan, EState *estate)
829 ResultRelInfo *resultRelInfo;
834 * shut down any PlanQual processing we were doing
836 if (estate->es_evalPlanQual != NULL)
837 EndEvalPlanQual(estate);
840 * shut down the node-type-specific query processing
842 ExecEndNode(plan, NULL);
845 * destroy the executor "tuple" table.
847 ExecDropTupleTable(estate->es_tupleTable, true);
848 estate->es_tupleTable = NULL;
851 * close the result relation(s) if any, but hold locks until xact
852 * commit. Also clean up junkfilters if present.
854 resultRelInfo = estate->es_result_relations;
855 for (i = estate->es_num_result_relations; i > 0; i--)
857 /* Close indices and then the relation itself */
858 ExecCloseIndices(resultRelInfo);
859 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
860 /* Delete the junkfilter if any */
861 if (resultRelInfo->ri_junkFilter != NULL)
862 ExecFreeJunkFilter(resultRelInfo->ri_junkFilter);
867 * close the "into" relation if necessary, again keeping lock
869 if (estate->es_into_relation_descriptor != NULL)
870 heap_close(estate->es_into_relation_descriptor, NoLock);
873 * There might be a junkfilter without a result relation.
875 if (estate->es_num_result_relations == 0 &&
876 estate->es_junkFilter != NULL)
878 ExecFreeJunkFilter(estate->es_junkFilter);
879 estate->es_junkFilter = NULL;
883 * close any relations selected FOR UPDATE, again keeping locks
885 foreach(l, estate->es_rowMark)
887 execRowMark *erm = lfirst(l);
889 heap_close(erm->relation, NoLock);
893 /* ----------------------------------------------------------------
896 * processes the query plan to retrieve 'numberTuples' tuples in the
897 * direction specified.
898 * Retrieves all tuples if numberTuples is 0
900 * result is either a slot containing the last tuple in the case
901 * of a SELECT or NULL otherwise.
903 * Note: the ctid attribute is a 'junk' attribute that is removed before the
905 * ----------------------------------------------------------------
907 static TupleTableSlot *
908 ExecutePlan(EState *estate,
912 ScanDirection direction,
913 DestReceiver *destfunc)
915 JunkFilter *junkfilter;
916 TupleTableSlot *slot;
917 ItemPointer tupleid = NULL;
918 ItemPointerData tuple_ctid;
919 long current_tuple_count;
920 TupleTableSlot *result;
923 * initialize local variables
926 current_tuple_count = 0;
932 estate->es_direction = direction;
935 * Loop until we've processed the proper number of tuples from the
941 /* Reset the per-output-tuple exprcontext */
942 ResetPerTupleExprContext(estate);
945 * Execute the plan and obtain a tuple
948 if (estate->es_useEvalPlan)
950 slot = EvalPlanQualNext(estate);
952 slot = ExecProcNode(plan, NULL);
955 slot = ExecProcNode(plan, NULL);
958 * if the tuple is null, then we assume there is nothing more to
959 * process so we just return null...
968 * if we have a junk filter, then project a new tuple with the
971 * Store this new "clean" tuple in the junkfilter's resultSlot.
972 * (Formerly, we stored it back over the "dirty" tuple, which is
973 * WRONG because that tuple slot has the wrong descriptor.)
975 * Also, extract all the junk information we need.
977 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
984 * extract the 'ctid' junk attribute.
986 if (operation == CMD_UPDATE || operation == CMD_DELETE)
988 if (!ExecGetJunkAttribute(junkfilter,
993 elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
995 /* shouldn't ever get a null result... */
997 elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
999 tupleid = (ItemPointer) DatumGetPointer(datum);
1000 tuple_ctid = *tupleid; /* make sure we don't free the
1002 tupleid = &tuple_ctid;
1004 else if (estate->es_rowMark != NIL)
1009 foreach(l, estate->es_rowMark)
1011 execRowMark *erm = lfirst(l);
1013 HeapTupleData tuple;
1014 TupleTableSlot *newSlot;
1017 if (!ExecGetJunkAttribute(junkfilter,
1022 elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
1025 /* shouldn't ever get a null result... */
1027 elog(ERROR, "ExecutePlan: (junk) `%s' is NULL!",
1030 tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1031 test = heap_mark4update(erm->relation, &tuple, &buffer,
1032 estate->es_snapshot->curcid);
1033 ReleaseBuffer(buffer);
1036 case HeapTupleSelfUpdated:
1037 /* treat it as deleted; do not process */
1040 case HeapTupleMayBeUpdated:
1043 case HeapTupleUpdated:
1044 if (XactIsoLevel == XACT_SERIALIZABLE)
1045 elog(ERROR, "Can't serialize access due to concurrent update");
1046 if (!(ItemPointerEquals(&(tuple.t_self),
1047 (ItemPointer) DatumGetPointer(datum))))
1049 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1050 if (!(TupIsNull(newSlot)))
1053 estate->es_useEvalPlan = true;
1059 * if tuple was deleted or PlanQual failed for
1060 * updated tuple - we must not return this
1066 elog(ERROR, "Unknown status %u from heap_mark4update", test);
1073 * Finally create a new "clean" tuple with all junk attributes
1076 newTuple = ExecRemoveJunk(junkfilter, slot);
1078 slot = ExecStoreTuple(newTuple, /* tuple to store */
1079 junkfilter->jf_resultSlot, /* dest slot */
1080 InvalidBuffer, /* this tuple has no
1082 true); /* tuple should be pfreed */
1086 * now that we have a tuple, do the appropriate thing with it..
1087 * either return it to the user, add it to a relation someplace,
1088 * delete it from a relation, or modify some of its attributes.
1093 ExecSelect(slot, /* slot containing tuple */
1094 destfunc, /* destination's tuple-receiver
1101 ExecInsert(slot, tupleid, estate);
1106 ExecDelete(slot, tupleid, estate);
1111 ExecUpdate(slot, tupleid, estate);
1116 elog(LOG, "ExecutePlan: unknown operation in queryDesc");
1122 * check our tuple count.. if we've processed the proper number
1123 * then quit, else loop again and process more tuples..
1125 current_tuple_count++;
1126 if (numberTuples == current_tuple_count)
1131 * here, result is either a slot containing a tuple in the case of a
1132 * SELECT or NULL otherwise.
1137 /* ----------------------------------------------------------------
1140 * SELECTs are easy.. we just pass the tuple to the appropriate
1141 * print function. The only complexity is when we do a
1142 * "SELECT INTO", in which case we insert the tuple into
1143 * the appropriate relation (note: this is a newly created relation
1144 * so we don't need to worry about indices or locks.)
1145 * ----------------------------------------------------------------
1148 ExecSelect(TupleTableSlot *slot,
1149 DestReceiver *destfunc,
1156 * get the heap tuple out of the tuple table slot
1159 attrtype = slot->ttc_tupleDescriptor;
1162 * insert the tuple into the "into relation"
1164 if (estate->es_into_relation_descriptor != NULL)
1166 heap_insert(estate->es_into_relation_descriptor, tuple,
1167 estate->es_snapshot->curcid);
1172 * send the tuple to the front end (or the screen)
1174 (*destfunc->receiveTuple) (tuple, attrtype, destfunc);
1176 (estate->es_processed)++;
1179 /* ----------------------------------------------------------------
1182 * INSERTs are trickier.. we have to insert the tuple into
1183 * the base relation and insert appropriate tuples into the
1185 * ----------------------------------------------------------------
1188 ExecInsert(TupleTableSlot *slot,
1189 ItemPointer tupleid,
1193 ResultRelInfo *resultRelInfo;
1194 Relation resultRelationDesc;
1199 * get the heap tuple out of the tuple table slot
1204 * get information on the (current) result relation
1206 resultRelInfo = estate->es_result_relation_info;
1207 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1209 /* BEFORE ROW INSERT Triggers */
1210 if (resultRelInfo->ri_TrigDesc &&
1211 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1215 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1217 if (newtuple == NULL) /* "do nothing" */
1220 if (newtuple != tuple) /* modified by Trigger(s) */
1223 * Insert modified tuple into tuple table slot, replacing the
1224 * original. We assume that it was allocated in per-tuple
1225 * memory context, and therefore will go away by itself. The
1226 * tuple table slot should not try to clear it.
1228 ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1234 * Check the constraints of the tuple
1236 if (resultRelationDesc->rd_att->constr)
1237 ExecConstraints("ExecInsert", resultRelInfo, slot, estate);
1242 newId = heap_insert(resultRelationDesc, tuple,
1243 estate->es_snapshot->curcid);
1246 (estate->es_processed)++;
1247 estate->es_lastoid = newId;
1248 setLastTid(&(tuple->t_self));
1253 * Note: heap_insert adds a new tuple to a relation. As a side effect,
1254 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1257 numIndices = resultRelInfo->ri_NumIndices;
1259 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1261 /* AFTER ROW INSERT Triggers */
1262 if (resultRelInfo->ri_TrigDesc)
1263 ExecARInsertTriggers(estate, resultRelInfo, tuple);
1266 /* ----------------------------------------------------------------
1269 * DELETE is like UPDATE, we delete the tuple and its
1271 * ----------------------------------------------------------------
1274 ExecDelete(TupleTableSlot *slot,
1275 ItemPointer tupleid,
1278 ResultRelInfo *resultRelInfo;
1279 Relation resultRelationDesc;
1280 ItemPointerData ctid;
1284 * get information on the (current) result relation
1286 resultRelInfo = estate->es_result_relation_info;
1287 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1289 /* BEFORE ROW DELETE Triggers */
1290 if (resultRelInfo->ri_TrigDesc &&
1291 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1295 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid);
1297 if (!dodelete) /* "do nothing" */
1305 result = heap_delete(resultRelationDesc, tupleid,
1307 estate->es_snapshot->curcid);
1310 case HeapTupleSelfUpdated:
1311 /* already deleted by self; nothing to do */
1314 case HeapTupleMayBeUpdated:
1317 case HeapTupleUpdated:
1318 if (XactIsoLevel == XACT_SERIALIZABLE)
1319 elog(ERROR, "Can't serialize access due to concurrent update");
1320 else if (!(ItemPointerEquals(tupleid, &ctid)))
1322 TupleTableSlot *epqslot = EvalPlanQual(estate,
1323 resultRelInfo->ri_RangeTableIndex, &ctid);
1325 if (!TupIsNull(epqslot))
1331 /* tuple already deleted; nothing to do */
1335 elog(ERROR, "Unknown status %u from heap_delete", result);
1340 (estate->es_processed)++;
1343 * Note: Normally one would think that we have to delete index tuples
1344 * associated with the heap tuple now..
1346 * ... but in POSTGRES, we have no need to do this because the vacuum
1347 * daemon automatically opens an index scan and deletes index tuples
1348 * when it finds deleted heap tuples. -cim 9/27/89
1351 /* AFTER ROW DELETE Triggers */
1352 if (resultRelInfo->ri_TrigDesc)
1353 ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1356 /* ----------------------------------------------------------------
1359 * note: we can't run UPDATE queries with transactions
1360 * off because UPDATEs are actually INSERTs and our
1361 * scan will mistakenly loop forever, updating the tuple
1362 * it just inserted.. This should be fixed but until it
1363 * is, we don't want to get stuck in an infinite loop
1364 * which corrupts your database..
1365 * ----------------------------------------------------------------
1368 ExecUpdate(TupleTableSlot *slot,
1369 ItemPointer tupleid,
1373 ResultRelInfo *resultRelInfo;
1374 Relation resultRelationDesc;
1375 ItemPointerData ctid;
1380 * abort the operation if not running transactions
1382 if (IsBootstrapProcessingMode())
1384 elog(WARNING, "ExecUpdate: UPDATE can't run without transactions");
1389 * get the heap tuple out of the tuple table slot
1394 * get information on the (current) result relation
1396 resultRelInfo = estate->es_result_relation_info;
1397 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1399 /* BEFORE ROW UPDATE Triggers */
1400 if (resultRelInfo->ri_TrigDesc &&
1401 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1405 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1408 if (newtuple == NULL) /* "do nothing" */
1411 if (newtuple != tuple) /* modified by Trigger(s) */
1414 * Insert modified tuple into tuple table slot, replacing the
1415 * original. We assume that it was allocated in per-tuple
1416 * memory context, and therefore will go away by itself. The
1417 * tuple table slot should not try to clear it.
1419 ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1425 * Check the constraints of the tuple
1427 * If we generate a new candidate tuple after EvalPlanQual testing, we
1428 * must loop back here and recheck constraints. (We don't need to
1429 * redo triggers, however. If there are any BEFORE triggers then
1430 * trigger.c will have done mark4update to lock the correct tuple, so
1431 * there's no need to do them again.)
1434 if (resultRelationDesc->rd_att->constr)
1435 ExecConstraints("ExecUpdate", resultRelInfo, slot, estate);
1438 * replace the heap tuple
1440 result = heap_update(resultRelationDesc, tupleid, tuple,
1442 estate->es_snapshot->curcid);
1445 case HeapTupleSelfUpdated:
1446 /* already deleted by self; nothing to do */
1449 case HeapTupleMayBeUpdated:
1452 case HeapTupleUpdated:
1453 if (XactIsoLevel == XACT_SERIALIZABLE)
1454 elog(ERROR, "Can't serialize access due to concurrent update");
1455 else if (!(ItemPointerEquals(tupleid, &ctid)))
1457 TupleTableSlot *epqslot = EvalPlanQual(estate,
1458 resultRelInfo->ri_RangeTableIndex, &ctid);
1460 if (!TupIsNull(epqslot))
1463 tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1464 slot = ExecStoreTuple(tuple,
1465 estate->es_junkFilter->jf_resultSlot,
1466 InvalidBuffer, true);
1470 /* tuple already deleted; nothing to do */
1474 elog(ERROR, "Unknown status %u from heap_update", result);
1479 (estate->es_processed)++;
1482 * Note: instead of having to update the old index tuples associated
1483 * with the heap tuple, all we do is form and insert new index tuples.
1484 * This is because UPDATEs are actually DELETEs and INSERTs and index
1485 * tuple deletion is done automagically by the vacuum daemon. All we
1486 * do is insert new index tuples. -cim 9/27/89
1492 * heap_update updates a tuple in the base relation by invalidating it
1493 * and then inserting a new tuple to the relation. As a side effect,
1494 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1495 * field. So we now insert index tuples using the new tupleid stored
1499 numIndices = resultRelInfo->ri_NumIndices;
1501 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1503 /* AFTER ROW UPDATE Triggers */
1504 if (resultRelInfo->ri_TrigDesc)
1505 ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1509 ExecRelCheck(ResultRelInfo *resultRelInfo,
1510 TupleTableSlot *slot, EState *estate)
1512 Relation rel = resultRelInfo->ri_RelationDesc;
1513 int ncheck = rel->rd_att->constr->num_check;
1514 ConstrCheck *check = rel->rd_att->constr->check;
1515 ExprContext *econtext;
1516 MemoryContext oldContext;
1521 * If first time through for this result relation, build expression
1522 * nodetrees for rel's constraint expressions. Keep them in the
1523 * per-query memory context so they'll survive throughout the query.
1525 if (resultRelInfo->ri_ConstraintExprs == NULL)
1527 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1528 resultRelInfo->ri_ConstraintExprs =
1529 (List **) palloc(ncheck * sizeof(List *));
1530 for (i = 0; i < ncheck; i++)
1532 qual = (List *) stringToNode(check[i].ccbin);
1533 resultRelInfo->ri_ConstraintExprs[i] = qual;
1535 MemoryContextSwitchTo(oldContext);
1539 * We will use the EState's per-tuple context for evaluating
1540 * constraint expressions (creating it if it's not already there).
1542 econtext = GetPerTupleExprContext(estate);
1544 /* Arrange for econtext's scan tuple to be the tuple under test */
1545 econtext->ecxt_scantuple = slot;
1547 /* And evaluate the constraints */
1548 for (i = 0; i < ncheck; i++)
1550 qual = resultRelInfo->ri_ConstraintExprs[i];
1553 * NOTE: SQL92 specifies that a NULL result from a constraint
1554 * expression is not to be treated as a failure. Therefore, tell
1555 * ExecQual to return TRUE for NULL.
1557 if (!ExecQual(qual, econtext, true))
1558 return check[i].ccname;
1561 /* NULL result means no error */
1562 return (char *) NULL;
1566 ExecConstraints(const char *caller, ResultRelInfo *resultRelInfo,
1567 TupleTableSlot *slot, EState *estate)
1569 Relation rel = resultRelInfo->ri_RelationDesc;
1570 HeapTuple tuple = slot->val;
1571 TupleConstr *constr = rel->rd_att->constr;
1575 if (constr->has_not_null)
1577 int natts = rel->rd_att->natts;
1580 for (attrChk = 1; attrChk <= natts; attrChk++)
1582 if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1583 heap_attisnull(tuple, attrChk))
1584 elog(ERROR, "%s: Fail to add null value in not null attribute %s",
1585 caller, NameStr(rel->rd_att->attrs[attrChk - 1]->attname));
1589 if (constr->num_check > 0)
1593 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1594 elog(ERROR, "%s: rejected due to CHECK constraint \"%s\" on \"%s\"",
1595 caller, failed, RelationGetRelationName(rel));
1600 * Check a modified tuple to see if we want to process its updated version
1601 * under READ COMMITTED rules.
1603 * See backend/executor/README for some info about how this works.
1606 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1611 HeapTupleData tuple;
1612 HeapTuple copyTuple = NULL;
1619 * find relation containing target tuple
1621 if (estate->es_result_relation_info != NULL &&
1622 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1623 relation = estate->es_result_relation_info->ri_RelationDesc;
1629 foreach(l, estate->es_rowMark)
1631 if (((execRowMark *) lfirst(l))->rti == rti)
1633 relation = ((execRowMark *) lfirst(l))->relation;
1637 if (relation == NULL)
1638 elog(ERROR, "EvalPlanQual: can't find RTE %d", (int) rti);
1644 * Loop here to deal with updated or busy tuples
1646 tuple.t_self = *tid;
1651 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1653 TransactionId xwait = SnapshotDirty->xmax;
1655 if (TransactionIdIsValid(SnapshotDirty->xmin))
1656 elog(ERROR, "EvalPlanQual: t_xmin is uncommitted ?!");
1659 * If tuple is being updated by other transaction then we have
1660 * to wait for its commit/abort.
1662 if (TransactionIdIsValid(xwait))
1664 ReleaseBuffer(buffer);
1665 XactLockTableWait(xwait);
1670 * We got tuple - now copy it for use by recheck query.
1672 copyTuple = heap_copytuple(&tuple);
1673 ReleaseBuffer(buffer);
1678 * Oops! Invalid tuple. Have to check is it updated or deleted.
1679 * Note that it's possible to get invalid SnapshotDirty->tid if
1680 * tuple updated by this transaction. Have we to check this ?
1682 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1683 !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1685 /* updated, so look at the updated copy */
1686 tuple.t_self = SnapshotDirty->tid;
1691 * Deleted or updated by this transaction; forget it.
1697 * For UPDATE/DELETE we have to return tid of actual row we're
1700 *tid = tuple.t_self;
1703 * Need to run a recheck subquery. Find or create a PQ stack entry.
1705 epq = (evalPlanQual *) estate->es_evalPlanQual;
1706 rtsize = length(estate->es_range_table);
1709 if (epq != NULL && epq->rti == 0)
1711 /* Top PQ stack entry is idle, so re-use it */
1712 Assert(!(estate->es_useEvalPlan) &&
1713 epq->estate.es_evalPlanQual == NULL);
1719 * If this is request for another RTE - Ra, - then we have to check
1720 * wasn't PlanQual requested for Ra already and if so then Ra' row was
1721 * updated again and we have to re-start old execution for Ra and
1722 * forget all what we done after Ra was suspended. Cool? -:))
1724 if (epq != NULL && epq->rti != rti &&
1725 epq->estate.es_evTuple[rti - 1] != NULL)
1729 evalPlanQual *oldepq;
1731 /* pop previous PlanQual from the stack */
1732 epqstate = &(epq->estate);
1733 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1734 Assert(oldepq->rti != 0);
1735 /* stop execution */
1736 ExecEndNode(epq->plan, NULL);
1737 ExecDropTupleTable(epqstate->es_tupleTable, true);
1738 epqstate->es_tupleTable = NULL;
1739 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1740 epqstate->es_evTuple[epq->rti - 1] = NULL;
1741 /* push current PQ to freePQ stack */
1744 estate->es_evalPlanQual = (Pointer) epq;
1745 } while (epq->rti != rti);
1749 * If we are requested for another RTE then we have to suspend
1750 * execution of current PlanQual and start execution for new one.
1752 if (epq == NULL || epq->rti != rti)
1754 /* try to reuse plan used previously */
1755 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1757 if (newepq == NULL) /* first call or freePQ stack is empty */
1759 newepq = (evalPlanQual *) palloc(sizeof(evalPlanQual));
1760 newepq->free = NULL;
1763 * Each stack level has its own copy of the plan tree. This
1764 * is wasteful, but necessary as long as plan nodes point to
1765 * exec state nodes rather than vice versa. Note that
1766 * copyfuncs.c doesn't attempt to copy the exec state nodes,
1767 * which is a good thing in this situation.
1769 newepq->plan = copyObject(estate->es_origPlan);
1772 * Init stack level's EState. We share top level's copy of
1773 * es_result_relations array and other non-changing status. We
1774 * need our own tupletable, es_param_exec_vals, and other
1777 epqstate = &(newepq->estate);
1778 memcpy(epqstate, estate, sizeof(EState));
1779 epqstate->es_direction = ForwardScanDirection;
1780 if (estate->es_origPlan->nParamExec > 0)
1781 epqstate->es_param_exec_vals = (ParamExecData *)
1782 palloc(estate->es_origPlan->nParamExec *
1783 sizeof(ParamExecData));
1784 epqstate->es_tupleTable = NULL;
1785 epqstate->es_per_tuple_exprcontext = NULL;
1788 * Each epqstate must have its own es_evTupleNull state, but
1789 * all the stack entries share es_evTuple state. This allows
1790 * sub-rechecks to inherit the value being examined by an
1793 epqstate->es_evTupleNull = (bool *) palloc(rtsize * sizeof(bool));
1796 /* first PQ stack entry */
1797 epqstate->es_evTuple = (HeapTuple *)
1798 palloc(rtsize * sizeof(HeapTuple));
1799 memset(epqstate->es_evTuple, 0, rtsize * sizeof(HeapTuple));
1803 /* later stack entries share the same storage */
1804 epqstate->es_evTuple = epq->estate.es_evTuple;
1809 /* recycle previously used EState */
1810 epqstate = &(newepq->estate);
1812 /* push current PQ to the stack */
1813 epqstate->es_evalPlanQual = (Pointer) epq;
1815 estate->es_evalPlanQual = (Pointer) epq;
1820 Assert(epq->rti == rti);
1821 epqstate = &(epq->estate);
1824 * Ok - we're requested for the same RTE. Unfortunately we still have
1825 * to end and restart execution of the plan, because ExecReScan
1826 * wouldn't ensure that upper plan nodes would reset themselves. We
1827 * could make that work if insertion of the target tuple were
1828 * integrated with the Param mechanism somehow, so that the upper plan
1829 * nodes know that their children's outputs have changed.
1833 /* stop execution */
1834 ExecEndNode(epq->plan, NULL);
1835 ExecDropTupleTable(epqstate->es_tupleTable, true);
1836 epqstate->es_tupleTable = NULL;
1840 * free old RTE' tuple, if any, and store target tuple where
1841 * relation's scan node will see it
1843 if (epqstate->es_evTuple[rti - 1] != NULL)
1844 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1845 epqstate->es_evTuple[rti - 1] = copyTuple;
1848 * Initialize for new recheck query; be careful to copy down state
1849 * that might have changed in top EState.
1851 epqstate->es_result_relation_info = estate->es_result_relation_info;
1852 epqstate->es_junkFilter = estate->es_junkFilter;
1853 if (estate->es_origPlan->nParamExec > 0)
1854 memset(epqstate->es_param_exec_vals, 0,
1855 estate->es_origPlan->nParamExec * sizeof(ParamExecData));
1856 memset(epqstate->es_evTupleNull, false, rtsize * sizeof(bool));
1857 epqstate->es_useEvalPlan = false;
1858 Assert(epqstate->es_tupleTable == NULL);
1859 epqstate->es_tupleTable =
1860 ExecCreateTupleTable(estate->es_tupleTable->size);
1862 ExecInitNode(epq->plan, epqstate, NULL);
1864 return EvalPlanQualNext(estate);
1867 static TupleTableSlot *
1868 EvalPlanQualNext(EState *estate)
1870 evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1871 EState *epqstate = &(epq->estate);
1872 evalPlanQual *oldepq;
1873 TupleTableSlot *slot;
1875 Assert(epq->rti != 0);
1878 slot = ExecProcNode(epq->plan, NULL);
1881 * No more tuples for this PQ. Continue previous one.
1883 if (TupIsNull(slot))
1885 /* stop execution */
1886 ExecEndNode(epq->plan, NULL);
1887 ExecDropTupleTable(epqstate->es_tupleTable, true);
1888 epqstate->es_tupleTable = NULL;
1889 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1890 epqstate->es_evTuple[epq->rti - 1] = NULL;
1891 /* pop old PQ from the stack */
1892 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1893 if (oldepq == (evalPlanQual *) NULL)
1895 epq->rti = 0; /* this is the first (oldest) */
1896 estate->es_useEvalPlan = false; /* PQ - mark as free and */
1897 return (NULL); /* continue Query execution */
1899 Assert(oldepq->rti != 0);
1900 /* push current PQ to freePQ stack */
1903 epqstate = &(epq->estate);
1904 estate->es_evalPlanQual = (Pointer) epq;
1912 EndEvalPlanQual(EState *estate)
1914 evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1915 EState *epqstate = &(epq->estate);
1916 evalPlanQual *oldepq;
1918 if (epq->rti == 0) /* plans already shutdowned */
1920 Assert(epq->estate.es_evalPlanQual == NULL);
1926 /* stop execution */
1927 ExecEndNode(epq->plan, NULL);
1928 ExecDropTupleTable(epqstate->es_tupleTable, true);
1929 epqstate->es_tupleTable = NULL;
1930 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1932 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1933 epqstate->es_evTuple[epq->rti - 1] = NULL;
1935 /* pop old PQ from the stack */
1936 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1937 if (oldepq == (evalPlanQual *) NULL)
1939 epq->rti = 0; /* this is the first (oldest) */
1940 estate->es_useEvalPlan = false; /* PQ - mark as free */
1943 Assert(oldepq->rti != 0);
1944 /* push current PQ to freePQ stack */
1947 epqstate = &(epq->estate);
1948 estate->es_evalPlanQual = (Pointer) epq;