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11 * The old ExecutorMain() has been replaced by ExecutorStart(),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 * $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.232 2004/05/26 04:41:14 neilc 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/clauses.h"
44 #include "optimizer/var.h"
45 #include "parser/parsetree.h"
46 #include "utils/acl.h"
47 #include "utils/guc.h"
48 #include "utils/lsyscache.h"
51 typedef struct execRowMark
58 typedef struct evalPlanQual
63 struct evalPlanQual *next; /* stack of active PlanQual plans */
64 struct evalPlanQual *free; /* list of free PlanQual plans */
67 /* decls for local routines only used within this module */
68 static void InitPlan(QueryDesc *queryDesc, bool explainOnly);
69 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
70 Index resultRelationIndex,
73 static TupleTableSlot *ExecutePlan(EState *estate, PlanState *planstate,
76 ScanDirection direction,
78 static void ExecSelect(TupleTableSlot *slot,
81 static void ExecInsert(TupleTableSlot *slot, ItemPointer tupleid,
83 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
85 static void ExecUpdate(TupleTableSlot *slot, ItemPointer tupleid,
87 static TupleTableSlot *EvalPlanQualNext(EState *estate);
88 static void EndEvalPlanQual(EState *estate);
89 static void ExecCheckRTEPerms(RangeTblEntry *rte);
90 static void ExecCheckXactReadOnly(Query *parsetree);
91 static void EvalPlanQualStart(evalPlanQual *epq, EState *estate,
92 evalPlanQual *priorepq);
93 static void EvalPlanQualStop(evalPlanQual *epq);
95 /* end of local decls */
98 /* ----------------------------------------------------------------
101 * This routine must be called at the beginning of any execution of any
104 * Takes a QueryDesc previously created by CreateQueryDesc (it's not real
105 * clear why we bother to separate the two functions, but...). The tupDesc
106 * field of the QueryDesc is filled in to describe the tuples that will be
107 * returned, and the internal fields (estate and planstate) are set up.
109 * If useCurrentSnapshot is true, run the query with the latest available
110 * snapshot, instead of the normal QuerySnapshot. Also, if it's an update
111 * or delete query, check that the rows to be updated or deleted would be
112 * visible to the normal QuerySnapshot. (This is a special-case behavior
113 * needed for referential integrity updates in serializable transactions.
114 * We must check all currently-committed rows, but we want to throw a
115 * can't-serialize error if any rows that would need updates would not be
116 * visible under the normal serializable snapshot.)
118 * If explainOnly is true, we are not actually intending to run the plan,
119 * only to set up for EXPLAIN; so skip unwanted side-effects.
121 * NB: the CurrentMemoryContext when this is called will become the parent
122 * of the per-query context used for this Executor invocation.
123 * ----------------------------------------------------------------
126 ExecutorStart(QueryDesc *queryDesc, bool useCurrentSnapshot, bool explainOnly)
129 MemoryContext oldcontext;
131 /* sanity checks: queryDesc must not be started already */
132 Assert(queryDesc != NULL);
133 Assert(queryDesc->estate == NULL);
136 * If the transaction is read-only, we need to check if any writes are
137 * planned to non-temporary tables.
139 if (XactReadOnly && !explainOnly)
140 ExecCheckXactReadOnly(queryDesc->parsetree);
143 * Build EState, switch into per-query memory context for startup.
145 estate = CreateExecutorState();
146 queryDesc->estate = estate;
148 oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
151 * Fill in parameters, if any, from queryDesc
153 estate->es_param_list_info = queryDesc->params;
155 if (queryDesc->plantree->nParamExec > 0)
156 estate->es_param_exec_vals = (ParamExecData *)
157 palloc0(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
159 estate->es_instrument = queryDesc->doInstrument;
162 * Make our own private copy of the current query snapshot data.
164 * This "freezes" our idea of which tuples are good and which are not for
165 * the life of this query, even if it outlives the current command and
168 if (useCurrentSnapshot)
170 /* RI update/delete query --- must use an up-to-date snapshot */
171 estate->es_snapshot = CopyCurrentSnapshot();
172 /* crosscheck updates/deletes against transaction snapshot */
173 estate->es_crosscheck_snapshot = CopyQuerySnapshot();
177 /* normal query --- use query snapshot, no crosscheck */
178 estate->es_snapshot = CopyQuerySnapshot();
179 estate->es_crosscheck_snapshot = SnapshotAny;
183 * Initialize the plan state tree
185 InitPlan(queryDesc, explainOnly);
187 MemoryContextSwitchTo(oldcontext);
190 /* ----------------------------------------------------------------
193 * This is the main routine of the executor module. It accepts
194 * the query descriptor from the traffic cop and executes the
197 * ExecutorStart must have been called already.
199 * If direction is NoMovementScanDirection then nothing is done
200 * except to start up/shut down the destination. Otherwise,
201 * we retrieve up to 'count' tuples in the specified direction.
203 * Note: count = 0 is interpreted as no portal limit, i.e., run to
206 * ----------------------------------------------------------------
209 ExecutorRun(QueryDesc *queryDesc,
210 ScanDirection direction, long count)
215 TupleTableSlot *result;
216 MemoryContext oldcontext;
219 Assert(queryDesc != NULL);
221 estate = queryDesc->estate;
223 Assert(estate != NULL);
226 * Switch into per-query memory context
228 oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
231 * extract information from the query descriptor and the query
234 operation = queryDesc->operation;
235 dest = queryDesc->dest;
238 * startup tuple receiver
240 estate->es_processed = 0;
241 estate->es_lastoid = InvalidOid;
243 (*dest->rStartup) (dest, operation, queryDesc->tupDesc);
248 if (direction == NoMovementScanDirection)
251 result = ExecutePlan(estate,
252 queryDesc->planstate,
261 (*dest->rShutdown) (dest);
263 MemoryContextSwitchTo(oldcontext);
268 /* ----------------------------------------------------------------
271 * This routine must be called at the end of execution of any
273 * ----------------------------------------------------------------
276 ExecutorEnd(QueryDesc *queryDesc)
279 MemoryContext oldcontext;
282 Assert(queryDesc != NULL);
284 estate = queryDesc->estate;
286 Assert(estate != NULL);
289 * Switch into per-query memory context to run ExecEndPlan
291 oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
293 ExecEndPlan(queryDesc->planstate, estate);
296 * Must switch out of context before destroying it
298 MemoryContextSwitchTo(oldcontext);
301 * Release EState and per-query memory context. This should release
302 * everything the executor has allocated.
304 FreeExecutorState(estate);
306 /* Reset queryDesc fields that no longer point to anything */
307 queryDesc->tupDesc = NULL;
308 queryDesc->estate = NULL;
309 queryDesc->planstate = NULL;
312 /* ----------------------------------------------------------------
315 * This routine may be called on an open queryDesc to rewind it
317 * ----------------------------------------------------------------
320 ExecutorRewind(QueryDesc *queryDesc)
323 MemoryContext oldcontext;
326 Assert(queryDesc != NULL);
328 estate = queryDesc->estate;
330 Assert(estate != NULL);
332 /* It's probably not sensible to rescan updating queries */
333 Assert(queryDesc->operation == CMD_SELECT);
336 * Switch into per-query memory context
338 oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
343 ExecReScan(queryDesc->planstate, NULL);
345 MemoryContextSwitchTo(oldcontext);
351 * Check access permissions for all relations listed in a range table.
354 ExecCheckRTPerms(List *rangeTable)
358 foreach(l, rangeTable)
360 RangeTblEntry *rte = lfirst(l);
362 ExecCheckRTEPerms(rte);
368 * Check access permissions for a single RTE.
371 ExecCheckRTEPerms(RangeTblEntry *rte)
373 AclMode requiredPerms;
378 * If it's a subquery, recursively examine its rangetable.
380 if (rte->rtekind == RTE_SUBQUERY)
382 ExecCheckRTPerms(rte->subquery->rtable);
387 * Otherwise, only plain-relation RTEs need to be checked here.
388 * Function RTEs are checked by init_fcache when the function is
389 * prepared for execution. Join and special RTEs need no checks.
391 if (rte->rtekind != RTE_RELATION)
395 * No work if requiredPerms is empty.
397 requiredPerms = rte->requiredPerms;
398 if (requiredPerms == 0)
404 * userid to check as: current user unless we have a setuid
407 * Note: GetUserId() is presently fast enough that there's no harm in
408 * calling it separately for each RTE. If that stops being true, we
409 * could call it once in ExecCheckRTPerms and pass the userid down
410 * from there. But for now, no need for the extra clutter.
412 userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
415 * We must have *all* the requiredPerms bits, so use aclmask not
418 if (pg_class_aclmask(relOid, userid, requiredPerms, ACLMASK_ALL)
420 aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_CLASS,
421 get_rel_name(relOid));
425 * Check that the query does not imply any writes to non-temp tables.
428 ExecCheckXactReadOnly(Query *parsetree)
433 * CREATE TABLE AS or SELECT INTO?
435 * XXX should we allow this if the destination is temp?
437 if (parsetree->into != NULL)
440 /* Fail if write permissions are requested on any non-temp table */
441 foreach(l, parsetree->rtable)
443 RangeTblEntry *rte = lfirst(l);
445 if (rte->rtekind == RTE_SUBQUERY)
447 ExecCheckXactReadOnly(rte->subquery);
451 if (rte->rtekind != RTE_RELATION)
454 if ((rte->requiredPerms & (~ACL_SELECT)) == 0)
457 if (isTempNamespace(get_rel_namespace(rte->relid)))
467 (errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION),
468 errmsg("transaction is read-only")));
472 /* ----------------------------------------------------------------
475 * Initializes the query plan: open files, allocate storage
476 * and start up the rule manager
477 * ----------------------------------------------------------------
480 InitPlan(QueryDesc *queryDesc, bool explainOnly)
482 CmdType operation = queryDesc->operation;
483 Query *parseTree = queryDesc->parsetree;
484 Plan *plan = queryDesc->plantree;
485 EState *estate = queryDesc->estate;
486 PlanState *planstate;
488 Relation intoRelationDesc;
493 * Do permissions checks. It's sufficient to examine the query's top
494 * rangetable here --- subplan RTEs will be checked during
497 ExecCheckRTPerms(parseTree->rtable);
500 * get information from query descriptor
502 rangeTable = parseTree->rtable;
505 * initialize the node's execution state
507 estate->es_range_table = rangeTable;
510 * if there is a result relation, initialize result relation stuff
512 if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
514 List *resultRelations = parseTree->resultRelations;
515 int numResultRelations;
516 ResultRelInfo *resultRelInfos;
518 if (resultRelations != NIL)
521 * Multiple result relations (due to inheritance)
522 * parseTree->resultRelations identifies them all
524 ResultRelInfo *resultRelInfo;
527 numResultRelations = length(resultRelations);
528 resultRelInfos = (ResultRelInfo *)
529 palloc(numResultRelations * sizeof(ResultRelInfo));
530 resultRelInfo = resultRelInfos;
531 foreach(l, resultRelations)
533 initResultRelInfo(resultRelInfo,
543 * Single result relation identified by
544 * parseTree->resultRelation
546 numResultRelations = 1;
547 resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
548 initResultRelInfo(resultRelInfos,
549 parseTree->resultRelation,
554 estate->es_result_relations = resultRelInfos;
555 estate->es_num_result_relations = numResultRelations;
556 /* Initialize to first or only result rel */
557 estate->es_result_relation_info = resultRelInfos;
562 * if no result relation, then set state appropriately
564 estate->es_result_relations = NULL;
565 estate->es_num_result_relations = 0;
566 estate->es_result_relation_info = NULL;
570 * Detect whether we're doing SELECT INTO. If so, set the force_oids
571 * flag appropriately so that the plan tree will be initialized with
572 * the correct tuple descriptors.
574 do_select_into = false;
576 if (operation == CMD_SELECT && parseTree->into != NULL)
578 do_select_into = true;
579 estate->es_select_into = true;
580 estate->es_into_oids = parseTree->intoHasOids;
584 * Have to lock relations selected for update
586 estate->es_rowMark = NIL;
587 if (parseTree->rowMarks != NIL)
591 foreach(l, parseTree->rowMarks)
593 Index rti = lfirsti(l);
594 Oid relid = getrelid(rti, rangeTable);
598 relation = heap_open(relid, RowShareLock);
599 erm = (execRowMark *) palloc(sizeof(execRowMark));
600 erm->relation = relation;
602 snprintf(erm->resname, sizeof(erm->resname), "ctid%u", rti);
603 estate->es_rowMark = lappend(estate->es_rowMark, erm);
608 * initialize the executor "tuple" table. We need slots for all the
609 * plan nodes, plus possibly output slots for the junkfilter(s). At
610 * this point we aren't sure if we need junkfilters, so just add slots
611 * for them unconditionally.
614 int nSlots = ExecCountSlotsNode(plan);
616 if (parseTree->resultRelations != NIL)
617 nSlots += length(parseTree->resultRelations);
620 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
623 /* mark EvalPlanQual not active */
624 estate->es_topPlan = plan;
625 estate->es_evalPlanQual = NULL;
626 estate->es_evTupleNull = NULL;
627 estate->es_evTuple = NULL;
628 estate->es_useEvalPlan = false;
631 * initialize the private state information for all the nodes in the
632 * query tree. This opens files, allocates storage and leaves us
633 * ready to start processing tuples.
635 planstate = ExecInitNode(plan, estate);
638 * Get the tuple descriptor describing the type of tuples to return.
639 * (this is especially important if we are creating a relation with
642 tupType = ExecGetResultType(planstate);
645 * Initialize the junk filter if needed. SELECT and INSERT queries
646 * need a filter if there are any junk attrs in the tlist. INSERT and
647 * SELECT INTO also need a filter if the plan may return raw disk tuples
648 * (else heap_insert will be scribbling on the source relation!).
649 * UPDATE and DELETE always need a filter, since there's always a junk
650 * 'ctid' attribute present --- no need to look first.
653 bool junk_filter_needed = false;
660 foreach(tlist, plan->targetlist)
662 TargetEntry *tle = (TargetEntry *) lfirst(tlist);
664 if (tle->resdom->resjunk)
666 junk_filter_needed = true;
670 if (!junk_filter_needed &&
671 (operation == CMD_INSERT || do_select_into) &&
672 ExecMayReturnRawTuples(planstate))
673 junk_filter_needed = true;
677 junk_filter_needed = true;
683 if (junk_filter_needed)
686 * If there are multiple result relations, each one needs its
687 * own junk filter. Note this is only possible for
688 * UPDATE/DELETE, so we can't be fooled by some needing a
689 * filter and some not.
691 if (parseTree->resultRelations != NIL)
693 PlanState **appendplans;
695 ResultRelInfo *resultRelInfo;
698 /* Top plan had better be an Append here. */
699 Assert(IsA(plan, Append));
700 Assert(((Append *) plan)->isTarget);
701 Assert(IsA(planstate, AppendState));
702 appendplans = ((AppendState *) planstate)->appendplans;
703 as_nplans = ((AppendState *) planstate)->as_nplans;
704 Assert(as_nplans == estate->es_num_result_relations);
705 resultRelInfo = estate->es_result_relations;
706 for (i = 0; i < as_nplans; i++)
708 PlanState *subplan = appendplans[i];
711 j = ExecInitJunkFilter(subplan->plan->targetlist,
712 ExecGetResultType(subplan),
713 ExecAllocTableSlot(estate->es_tupleTable));
714 resultRelInfo->ri_junkFilter = j;
719 * Set active junkfilter too; at this point ExecInitAppend
720 * has already selected an active result relation...
722 estate->es_junkFilter =
723 estate->es_result_relation_info->ri_junkFilter;
727 /* Normal case with just one JunkFilter */
730 j = ExecInitJunkFilter(planstate->plan->targetlist,
732 ExecAllocTableSlot(estate->es_tupleTable));
733 estate->es_junkFilter = j;
734 if (estate->es_result_relation_info)
735 estate->es_result_relation_info->ri_junkFilter = j;
737 /* For SELECT, want to return the cleaned tuple type */
738 if (operation == CMD_SELECT)
739 tupType = j->jf_cleanTupType;
743 estate->es_junkFilter = NULL;
747 * If doing SELECT INTO, initialize the "into" relation. We must wait
748 * till now so we have the "clean" result tuple type to create the new
751 * If EXPLAIN, skip creating the "into" relation.
753 intoRelationDesc = NULL;
755 if (do_select_into && !explainOnly)
764 * find namespace to create in, check permissions
766 intoName = parseTree->into->relname;
767 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
769 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
771 if (aclresult != ACLCHECK_OK)
772 aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
773 get_namespace_name(namespaceId));
776 * have to copy tupType to get rid of constraints
778 tupdesc = CreateTupleDescCopy(tupType);
780 intoRelationId = heap_create_with_catalog(intoName,
788 allowSystemTableMods);
790 FreeTupleDesc(tupdesc);
793 * Advance command counter so that the newly-created relation's
794 * catalog tuples will be visible to heap_open.
796 CommandCounterIncrement();
799 * If necessary, create a TOAST table for the into relation. Note
800 * that AlterTableCreateToastTable ends with
801 * CommandCounterIncrement(), so that the TOAST table will be
802 * visible for insertion.
804 AlterTableCreateToastTable(intoRelationId, true);
807 * And open the constructed table for writing.
809 intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock);
812 estate->es_into_relation_descriptor = intoRelationDesc;
814 queryDesc->tupDesc = tupType;
815 queryDesc->planstate = planstate;
819 * Initialize ResultRelInfo data for one result relation
822 initResultRelInfo(ResultRelInfo *resultRelInfo,
823 Index resultRelationIndex,
827 Oid resultRelationOid;
828 Relation resultRelationDesc;
830 resultRelationOid = getrelid(resultRelationIndex, rangeTable);
831 resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
833 switch (resultRelationDesc->rd_rel->relkind)
835 case RELKIND_SEQUENCE:
837 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
838 errmsg("cannot change sequence \"%s\"",
839 RelationGetRelationName(resultRelationDesc))));
841 case RELKIND_TOASTVALUE:
843 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
844 errmsg("cannot change TOAST relation \"%s\"",
845 RelationGetRelationName(resultRelationDesc))));
849 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
850 errmsg("cannot change view \"%s\"",
851 RelationGetRelationName(resultRelationDesc))));
855 MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
856 resultRelInfo->type = T_ResultRelInfo;
857 resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
858 resultRelInfo->ri_RelationDesc = resultRelationDesc;
859 resultRelInfo->ri_NumIndices = 0;
860 resultRelInfo->ri_IndexRelationDescs = NULL;
861 resultRelInfo->ri_IndexRelationInfo = NULL;
862 /* make a copy so as not to depend on relcache info not changing... */
863 resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
864 resultRelInfo->ri_TrigFunctions = NULL;
865 resultRelInfo->ri_ConstraintExprs = NULL;
866 resultRelInfo->ri_junkFilter = NULL;
869 * If there are indices on the result relation, open them and save
870 * descriptors in the result relation info, so that we can add new
871 * index entries for the tuples we add/update. We need not do this
872 * for a DELETE, however, since deletion doesn't affect indexes.
874 if (resultRelationDesc->rd_rel->relhasindex &&
875 operation != CMD_DELETE)
876 ExecOpenIndices(resultRelInfo);
880 * ExecContextForcesOids
882 * This is pretty grotty: when doing INSERT, UPDATE, or SELECT INTO,
883 * we need to ensure that result tuples have space for an OID iff they are
884 * going to be stored into a relation that has OIDs. In other contexts
885 * we are free to choose whether to leave space for OIDs in result tuples
886 * (we generally don't want to, but we do if a physical-tlist optimization
887 * is possible). This routine checks the plan context and returns TRUE if the
888 * choice is forced, FALSE if the choice is not forced. In the TRUE case,
889 * *hasoids is set to the required value.
891 * One reason this is ugly is that all plan nodes in the plan tree will emit
892 * tuples with space for an OID, though we really only need the topmost node
893 * to do so. However, node types like Sort don't project new tuples but just
894 * return their inputs, and in those cases the requirement propagates down
895 * to the input node. Eventually we might make this code smart enough to
896 * recognize how far down the requirement really goes, but for now we just
897 * make all plan nodes do the same thing if the top level forces the choice.
899 * We assume that estate->es_result_relation_info is already set up to
900 * describe the target relation. Note that in an UPDATE that spans an
901 * inheritance tree, some of the target relations may have OIDs and some not.
902 * We have to make the decisions on a per-relation basis as we initialize
903 * each of the child plans of the topmost Append plan.
905 * SELECT INTO is even uglier, because we don't have the INTO relation's
906 * descriptor available when this code runs; we have to look aside at a
907 * flag set by InitPlan().
910 ExecContextForcesOids(PlanState *planstate, bool *hasoids)
912 if (planstate->state->es_select_into)
914 *hasoids = planstate->state->es_into_oids;
919 ResultRelInfo *ri = planstate->state->es_result_relation_info;
923 Relation rel = ri->ri_RelationDesc;
927 *hasoids = rel->rd_rel->relhasoids;
936 /* ----------------------------------------------------------------
939 * Cleans up the query plan -- closes files and frees up storage
941 * NOTE: we are no longer very worried about freeing storage per se
942 * in this code; FreeExecutorState should be guaranteed to release all
943 * memory that needs to be released. What we are worried about doing
944 * is closing relations and dropping buffer pins. Thus, for example,
945 * tuple tables must be cleared or dropped to ensure pins are released.
946 * ----------------------------------------------------------------
949 ExecEndPlan(PlanState *planstate, EState *estate)
951 ResultRelInfo *resultRelInfo;
956 * shut down any PlanQual processing we were doing
958 if (estate->es_evalPlanQual != NULL)
959 EndEvalPlanQual(estate);
962 * shut down the node-type-specific query processing
964 ExecEndNode(planstate);
967 * destroy the executor "tuple" table.
969 ExecDropTupleTable(estate->es_tupleTable, true);
970 estate->es_tupleTable = NULL;
973 * close the result relation(s) if any, but hold locks until xact
976 resultRelInfo = estate->es_result_relations;
977 for (i = estate->es_num_result_relations; i > 0; i--)
979 /* Close indices and then the relation itself */
980 ExecCloseIndices(resultRelInfo);
981 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
986 * close the "into" relation if necessary, again keeping lock
988 if (estate->es_into_relation_descriptor != NULL)
989 heap_close(estate->es_into_relation_descriptor, NoLock);
992 * close any relations selected FOR UPDATE, again keeping locks
994 foreach(l, estate->es_rowMark)
996 execRowMark *erm = lfirst(l);
998 heap_close(erm->relation, NoLock);
1002 /* ----------------------------------------------------------------
1005 * processes the query plan to retrieve 'numberTuples' tuples in the
1006 * direction specified.
1008 * Retrieves all tuples if numberTuples is 0
1010 * result is either a slot containing the last tuple in the case
1011 * of a SELECT or NULL otherwise.
1013 * Note: the ctid attribute is a 'junk' attribute that is removed before the
1015 * ----------------------------------------------------------------
1017 static TupleTableSlot *
1018 ExecutePlan(EState *estate,
1019 PlanState *planstate,
1022 ScanDirection direction,
1025 JunkFilter *junkfilter;
1026 TupleTableSlot *slot;
1027 ItemPointer tupleid = NULL;
1028 ItemPointerData tuple_ctid;
1029 long current_tuple_count;
1030 TupleTableSlot *result;
1033 * initialize local variables
1036 current_tuple_count = 0;
1040 * Set the direction.
1042 estate->es_direction = direction;
1045 * Process BEFORE EACH STATEMENT triggers
1050 ExecBSUpdateTriggers(estate, estate->es_result_relation_info);
1053 ExecBSDeleteTriggers(estate, estate->es_result_relation_info);
1056 ExecBSInsertTriggers(estate, estate->es_result_relation_info);
1064 * Loop until we've processed the proper number of tuples from the
1070 /* Reset the per-output-tuple exprcontext */
1071 ResetPerTupleExprContext(estate);
1074 * Execute the plan and obtain a tuple
1077 if (estate->es_useEvalPlan)
1079 slot = EvalPlanQualNext(estate);
1080 if (TupIsNull(slot))
1081 slot = ExecProcNode(planstate);
1084 slot = ExecProcNode(planstate);
1087 * if the tuple is null, then we assume there is nothing more to
1088 * process so we just return null...
1090 if (TupIsNull(slot))
1097 * if we have a junk filter, then project a new tuple with the
1100 * Store this new "clean" tuple in the junkfilter's resultSlot.
1101 * (Formerly, we stored it back over the "dirty" tuple, which is
1102 * WRONG because that tuple slot has the wrong descriptor.)
1104 * Also, extract all the junk information we need.
1106 if ((junkfilter = estate->es_junkFilter) != NULL)
1113 * extract the 'ctid' junk attribute.
1115 if (operation == CMD_UPDATE || operation == CMD_DELETE)
1117 if (!ExecGetJunkAttribute(junkfilter,
1122 elog(ERROR, "could not find junk ctid column");
1124 /* shouldn't ever get a null result... */
1126 elog(ERROR, "ctid is NULL");
1128 tupleid = (ItemPointer) DatumGetPointer(datum);
1129 tuple_ctid = *tupleid; /* make sure we don't free the
1131 tupleid = &tuple_ctid;
1133 else if (estate->es_rowMark != NIL)
1138 foreach(l, estate->es_rowMark)
1140 execRowMark *erm = lfirst(l);
1142 HeapTupleData tuple;
1143 TupleTableSlot *newSlot;
1146 if (!ExecGetJunkAttribute(junkfilter,
1151 elog(ERROR, "could not find junk \"%s\" column",
1154 /* shouldn't ever get a null result... */
1156 elog(ERROR, "\"%s\" is NULL", erm->resname);
1158 tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1159 test = heap_mark4update(erm->relation, &tuple, &buffer,
1160 estate->es_snapshot->curcid);
1161 ReleaseBuffer(buffer);
1164 case HeapTupleSelfUpdated:
1165 /* treat it as deleted; do not process */
1168 case HeapTupleMayBeUpdated:
1171 case HeapTupleUpdated:
1172 if (IsXactIsoLevelSerializable)
1174 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1175 errmsg("could not serialize access due to concurrent update")));
1176 if (!(ItemPointerEquals(&(tuple.t_self),
1177 (ItemPointer) DatumGetPointer(datum))))
1179 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1180 if (!(TupIsNull(newSlot)))
1183 estate->es_useEvalPlan = true;
1189 * if tuple was deleted or PlanQual failed for
1190 * updated tuple - we must not return this
1196 elog(ERROR, "unrecognized heap_mark4update status: %u",
1204 * Finally create a new "clean" tuple with all junk attributes
1207 newTuple = ExecRemoveJunk(junkfilter, slot);
1209 slot = ExecStoreTuple(newTuple, /* tuple to store */
1210 junkfilter->jf_resultSlot, /* dest slot */
1211 InvalidBuffer, /* this tuple has no
1213 true); /* tuple should be pfreed */
1217 * now that we have a tuple, do the appropriate thing with it..
1218 * either return it to the user, add it to a relation someplace,
1219 * delete it from a relation, or modify some of its attributes.
1224 ExecSelect(slot, /* slot containing tuple */
1225 dest, /* destination's tuple-receiver obj */
1231 ExecInsert(slot, tupleid, estate);
1236 ExecDelete(slot, tupleid, estate);
1241 ExecUpdate(slot, tupleid, estate);
1246 elog(ERROR, "unrecognized operation code: %d",
1253 * check our tuple count.. if we've processed the proper number
1254 * then quit, else loop again and process more tuples. Zero
1255 * numberTuples means no limit.
1257 current_tuple_count++;
1258 if (numberTuples && numberTuples == current_tuple_count)
1263 * Process AFTER EACH STATEMENT triggers
1268 ExecASUpdateTriggers(estate, estate->es_result_relation_info);
1271 ExecASDeleteTriggers(estate, estate->es_result_relation_info);
1274 ExecASInsertTriggers(estate, estate->es_result_relation_info);
1282 * here, result is either a slot containing a tuple in the case of a
1283 * SELECT or NULL otherwise.
1288 /* ----------------------------------------------------------------
1291 * SELECTs are easy.. we just pass the tuple to the appropriate
1292 * print function. The only complexity is when we do a
1293 * "SELECT INTO", in which case we insert the tuple into
1294 * the appropriate relation (note: this is a newly created relation
1295 * so we don't need to worry about indices or locks.)
1296 * ----------------------------------------------------------------
1299 ExecSelect(TupleTableSlot *slot,
1307 * get the heap tuple out of the tuple table slot
1310 attrtype = slot->ttc_tupleDescriptor;
1313 * insert the tuple into the "into relation"
1315 * XXX this probably ought to be replaced by a separate destination
1317 if (estate->es_into_relation_descriptor != NULL)
1319 heap_insert(estate->es_into_relation_descriptor, tuple,
1320 estate->es_snapshot->curcid);
1325 * send the tuple to the destination
1327 (*dest->receiveTuple) (tuple, attrtype, dest);
1329 (estate->es_processed)++;
1332 /* ----------------------------------------------------------------
1335 * INSERTs are trickier.. we have to insert the tuple into
1336 * the base relation and insert appropriate tuples into the
1338 * ----------------------------------------------------------------
1341 ExecInsert(TupleTableSlot *slot,
1342 ItemPointer tupleid,
1346 ResultRelInfo *resultRelInfo;
1347 Relation resultRelationDesc;
1352 * get the heap tuple out of the tuple table slot
1357 * get information on the (current) result relation
1359 resultRelInfo = estate->es_result_relation_info;
1360 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1362 /* BEFORE ROW INSERT Triggers */
1363 if (resultRelInfo->ri_TrigDesc &&
1364 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1368 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1370 if (newtuple == NULL) /* "do nothing" */
1373 if (newtuple != tuple) /* modified by Trigger(s) */
1376 * Insert modified tuple into tuple table slot, replacing the
1377 * original. We assume that it was allocated in per-tuple
1378 * memory context, and therefore will go away by itself. The
1379 * tuple table slot should not try to clear it.
1381 ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1387 * Check the constraints of the tuple
1389 if (resultRelationDesc->rd_att->constr)
1390 ExecConstraints(resultRelInfo, slot, estate);
1395 newId = heap_insert(resultRelationDesc, tuple,
1396 estate->es_snapshot->curcid);
1399 (estate->es_processed)++;
1400 estate->es_lastoid = newId;
1401 setLastTid(&(tuple->t_self));
1406 * Note: heap_insert adds a new tuple to a relation. As a side effect,
1407 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1410 numIndices = resultRelInfo->ri_NumIndices;
1412 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1414 /* AFTER ROW INSERT Triggers */
1415 ExecARInsertTriggers(estate, resultRelInfo, tuple);
1418 /* ----------------------------------------------------------------
1421 * DELETE is like UPDATE, we delete the tuple and its
1423 * ----------------------------------------------------------------
1426 ExecDelete(TupleTableSlot *slot,
1427 ItemPointer tupleid,
1430 ResultRelInfo *resultRelInfo;
1431 Relation resultRelationDesc;
1432 ItemPointerData ctid;
1436 * get information on the (current) result relation
1438 resultRelInfo = estate->es_result_relation_info;
1439 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1441 /* BEFORE ROW DELETE Triggers */
1442 if (resultRelInfo->ri_TrigDesc &&
1443 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1447 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid,
1448 estate->es_snapshot->curcid);
1450 if (!dodelete) /* "do nothing" */
1458 result = heap_delete(resultRelationDesc, tupleid,
1460 estate->es_snapshot->curcid,
1461 estate->es_crosscheck_snapshot,
1462 true /* wait for commit */);
1465 case HeapTupleSelfUpdated:
1466 /* already deleted by self; nothing to do */
1469 case HeapTupleMayBeUpdated:
1472 case HeapTupleUpdated:
1473 if (IsXactIsoLevelSerializable)
1475 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1476 errmsg("could not serialize access due to concurrent update")));
1477 else if (!(ItemPointerEquals(tupleid, &ctid)))
1479 TupleTableSlot *epqslot = EvalPlanQual(estate,
1480 resultRelInfo->ri_RangeTableIndex, &ctid);
1482 if (!TupIsNull(epqslot))
1488 /* tuple already deleted; nothing to do */
1492 elog(ERROR, "unrecognized heap_delete status: %u", result);
1497 (estate->es_processed)++;
1500 * Note: Normally one would think that we have to delete index tuples
1501 * associated with the heap tuple now..
1503 * ... but in POSTGRES, we have no need to do this because the vacuum
1504 * daemon automatically opens an index scan and deletes index tuples
1505 * when it finds deleted heap tuples. -cim 9/27/89
1508 /* AFTER ROW DELETE Triggers */
1509 ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1512 /* ----------------------------------------------------------------
1515 * note: we can't run UPDATE queries with transactions
1516 * off because UPDATEs are actually INSERTs and our
1517 * scan will mistakenly loop forever, updating the tuple
1518 * it just inserted.. This should be fixed but until it
1519 * is, we don't want to get stuck in an infinite loop
1520 * which corrupts your database..
1521 * ----------------------------------------------------------------
1524 ExecUpdate(TupleTableSlot *slot,
1525 ItemPointer tupleid,
1529 ResultRelInfo *resultRelInfo;
1530 Relation resultRelationDesc;
1531 ItemPointerData ctid;
1536 * abort the operation if not running transactions
1538 if (IsBootstrapProcessingMode())
1539 elog(ERROR, "cannot UPDATE during bootstrap");
1542 * get the heap tuple out of the tuple table slot
1547 * get information on the (current) result relation
1549 resultRelInfo = estate->es_result_relation_info;
1550 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1552 /* BEFORE ROW UPDATE Triggers */
1553 if (resultRelInfo->ri_TrigDesc &&
1554 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1558 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1560 estate->es_snapshot->curcid);
1562 if (newtuple == NULL) /* "do nothing" */
1565 if (newtuple != tuple) /* modified by Trigger(s) */
1568 * Insert modified tuple into tuple table slot, replacing the
1569 * original. We assume that it was allocated in per-tuple
1570 * memory context, and therefore will go away by itself. The
1571 * tuple table slot should not try to clear it.
1573 ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1579 * Check the constraints of the tuple
1581 * If we generate a new candidate tuple after EvalPlanQual testing, we
1582 * must loop back here and recheck constraints. (We don't need to
1583 * redo triggers, however. If there are any BEFORE triggers then
1584 * trigger.c will have done mark4update to lock the correct tuple, so
1585 * there's no need to do them again.)
1588 if (resultRelationDesc->rd_att->constr)
1589 ExecConstraints(resultRelInfo, slot, estate);
1592 * replace the heap tuple
1594 result = heap_update(resultRelationDesc, tupleid, tuple,
1596 estate->es_snapshot->curcid,
1597 estate->es_crosscheck_snapshot,
1598 true /* wait for commit */);
1601 case HeapTupleSelfUpdated:
1602 /* already deleted by self; nothing to do */
1605 case HeapTupleMayBeUpdated:
1608 case HeapTupleUpdated:
1609 if (IsXactIsoLevelSerializable)
1611 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1612 errmsg("could not serialize access due to concurrent update")));
1613 else if (!(ItemPointerEquals(tupleid, &ctid)))
1615 TupleTableSlot *epqslot = EvalPlanQual(estate,
1616 resultRelInfo->ri_RangeTableIndex, &ctid);
1618 if (!TupIsNull(epqslot))
1621 tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1622 slot = ExecStoreTuple(tuple,
1623 estate->es_junkFilter->jf_resultSlot,
1624 InvalidBuffer, true);
1628 /* tuple already deleted; nothing to do */
1632 elog(ERROR, "unrecognized heap_update status: %u", result);
1637 (estate->es_processed)++;
1640 * Note: instead of having to update the old index tuples associated
1641 * with the heap tuple, all we do is form and insert new index tuples.
1642 * This is because UPDATEs are actually DELETEs and INSERTs and index
1643 * tuple deletion is done automagically by the vacuum daemon. All we
1644 * do is insert new index tuples. -cim 9/27/89
1650 * heap_update updates a tuple in the base relation by invalidating it
1651 * and then inserting a new tuple to the relation. As a side effect,
1652 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1653 * field. So we now insert index tuples using the new tupleid stored
1657 numIndices = resultRelInfo->ri_NumIndices;
1659 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1661 /* AFTER ROW UPDATE Triggers */
1662 ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1666 ExecRelCheck(ResultRelInfo *resultRelInfo,
1667 TupleTableSlot *slot, EState *estate)
1669 Relation rel = resultRelInfo->ri_RelationDesc;
1670 int ncheck = rel->rd_att->constr->num_check;
1671 ConstrCheck *check = rel->rd_att->constr->check;
1672 ExprContext *econtext;
1673 MemoryContext oldContext;
1678 * If first time through for this result relation, build expression
1679 * nodetrees for rel's constraint expressions. Keep them in the
1680 * per-query memory context so they'll survive throughout the query.
1682 if (resultRelInfo->ri_ConstraintExprs == NULL)
1684 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1685 resultRelInfo->ri_ConstraintExprs =
1686 (List **) palloc(ncheck * sizeof(List *));
1687 for (i = 0; i < ncheck; i++)
1689 /* ExecQual wants implicit-AND form */
1690 qual = make_ands_implicit(stringToNode(check[i].ccbin));
1691 resultRelInfo->ri_ConstraintExprs[i] = (List *)
1692 ExecPrepareExpr((Expr *) qual, estate);
1694 MemoryContextSwitchTo(oldContext);
1698 * We will use the EState's per-tuple context for evaluating
1699 * constraint expressions (creating it if it's not already there).
1701 econtext = GetPerTupleExprContext(estate);
1703 /* Arrange for econtext's scan tuple to be the tuple under test */
1704 econtext->ecxt_scantuple = slot;
1706 /* And evaluate the constraints */
1707 for (i = 0; i < ncheck; i++)
1709 qual = resultRelInfo->ri_ConstraintExprs[i];
1712 * NOTE: SQL92 specifies that a NULL result from a constraint
1713 * expression is not to be treated as a failure. Therefore, tell
1714 * ExecQual to return TRUE for NULL.
1716 if (!ExecQual(qual, econtext, true))
1717 return check[i].ccname;
1720 /* NULL result means no error */
1725 ExecConstraints(ResultRelInfo *resultRelInfo,
1726 TupleTableSlot *slot, EState *estate)
1728 Relation rel = resultRelInfo->ri_RelationDesc;
1729 HeapTuple tuple = slot->val;
1730 TupleConstr *constr = rel->rd_att->constr;
1734 if (constr->has_not_null)
1736 int natts = rel->rd_att->natts;
1739 for (attrChk = 1; attrChk <= natts; attrChk++)
1741 if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1742 heap_attisnull(tuple, attrChk))
1744 (errcode(ERRCODE_NOT_NULL_VIOLATION),
1745 errmsg("null value in column \"%s\" violates not-null constraint",
1746 NameStr(rel->rd_att->attrs[attrChk - 1]->attname))));
1750 if (constr->num_check > 0)
1754 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1756 (errcode(ERRCODE_CHECK_VIOLATION),
1757 errmsg("new row for relation \"%s\" violates check constraint \"%s\"",
1758 RelationGetRelationName(rel), failed)));
1763 * Check a modified tuple to see if we want to process its updated version
1764 * under READ COMMITTED rules.
1766 * See backend/executor/README for some info about how this works.
1769 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1774 HeapTupleData tuple;
1775 HeapTuple copyTuple = NULL;
1781 * find relation containing target tuple
1783 if (estate->es_result_relation_info != NULL &&
1784 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1785 relation = estate->es_result_relation_info->ri_RelationDesc;
1791 foreach(l, estate->es_rowMark)
1793 if (((execRowMark *) lfirst(l))->rti == rti)
1795 relation = ((execRowMark *) lfirst(l))->relation;
1799 if (relation == NULL)
1800 elog(ERROR, "could not find RowMark for RT index %u", rti);
1806 * Loop here to deal with updated or busy tuples
1808 tuple.t_self = *tid;
1813 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1815 TransactionId xwait = SnapshotDirty->xmax;
1817 /* xmin should not be dirty... */
1818 if (TransactionIdIsValid(SnapshotDirty->xmin))
1819 elog(ERROR, "t_xmin is uncommitted in tuple to be updated");
1822 * If tuple is being updated by other transaction then we have
1823 * to wait for its commit/abort.
1825 if (TransactionIdIsValid(xwait))
1827 ReleaseBuffer(buffer);
1828 XactLockTableWait(xwait);
1833 * We got tuple - now copy it for use by recheck query.
1835 copyTuple = heap_copytuple(&tuple);
1836 ReleaseBuffer(buffer);
1841 * Oops! Invalid tuple. Have to check is it updated or deleted.
1842 * Note that it's possible to get invalid SnapshotDirty->tid if
1843 * tuple updated by this transaction. Have we to check this ?
1845 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1846 !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1848 /* updated, so look at the updated copy */
1849 tuple.t_self = SnapshotDirty->tid;
1854 * Deleted or updated by this transaction; forget it.
1860 * For UPDATE/DELETE we have to return tid of actual row we're
1863 *tid = tuple.t_self;
1866 * Need to run a recheck subquery. Find or create a PQ stack entry.
1868 epq = estate->es_evalPlanQual;
1871 if (epq != NULL && epq->rti == 0)
1873 /* Top PQ stack entry is idle, so re-use it */
1874 Assert(!(estate->es_useEvalPlan) && epq->next == NULL);
1880 * If this is request for another RTE - Ra, - then we have to check
1881 * wasn't PlanQual requested for Ra already and if so then Ra' row was
1882 * updated again and we have to re-start old execution for Ra and
1883 * forget all what we done after Ra was suspended. Cool? -:))
1885 if (epq != NULL && epq->rti != rti &&
1886 epq->estate->es_evTuple[rti - 1] != NULL)
1890 evalPlanQual *oldepq;
1892 /* stop execution */
1893 EvalPlanQualStop(epq);
1894 /* pop previous PlanQual from the stack */
1896 Assert(oldepq && oldepq->rti != 0);
1897 /* push current PQ to freePQ stack */
1900 estate->es_evalPlanQual = epq;
1901 } while (epq->rti != rti);
1905 * If we are requested for another RTE then we have to suspend
1906 * execution of current PlanQual and start execution for new one.
1908 if (epq == NULL || epq->rti != rti)
1910 /* try to reuse plan used previously */
1911 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1913 if (newepq == NULL) /* first call or freePQ stack is empty */
1915 newepq = (evalPlanQual *) palloc0(sizeof(evalPlanQual));
1916 newepq->free = NULL;
1917 newepq->estate = NULL;
1918 newepq->planstate = NULL;
1922 /* recycle previously used PlanQual */
1923 Assert(newepq->estate == NULL);
1926 /* push current PQ to the stack */
1929 estate->es_evalPlanQual = epq;
1934 Assert(epq->rti == rti);
1937 * Ok - we're requested for the same RTE. Unfortunately we still have
1938 * to end and restart execution of the plan, because ExecReScan
1939 * wouldn't ensure that upper plan nodes would reset themselves. We
1940 * could make that work if insertion of the target tuple were
1941 * integrated with the Param mechanism somehow, so that the upper plan
1942 * nodes know that their children's outputs have changed.
1944 * Note that the stack of free evalPlanQual nodes is quite useless at the
1945 * moment, since it only saves us from pallocing/releasing the
1946 * evalPlanQual nodes themselves. But it will be useful once we
1947 * implement ReScan instead of end/restart for re-using PlanQual
1952 /* stop execution */
1953 EvalPlanQualStop(epq);
1957 * Initialize new recheck query.
1959 * Note: if we were re-using PlanQual plans via ExecReScan, we'd need to
1960 * instead copy down changeable state from the top plan (including
1961 * es_result_relation_info, es_junkFilter) and reset locally
1962 * changeable state in the epq (including es_param_exec_vals,
1965 EvalPlanQualStart(epq, estate, epq->next);
1968 * free old RTE' tuple, if any, and store target tuple where
1969 * relation's scan node will see it
1971 epqstate = epq->estate;
1972 if (epqstate->es_evTuple[rti - 1] != NULL)
1973 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1974 epqstate->es_evTuple[rti - 1] = copyTuple;
1976 return EvalPlanQualNext(estate);
1979 static TupleTableSlot *
1980 EvalPlanQualNext(EState *estate)
1982 evalPlanQual *epq = estate->es_evalPlanQual;
1983 MemoryContext oldcontext;
1984 TupleTableSlot *slot;
1986 Assert(epq->rti != 0);
1989 oldcontext = MemoryContextSwitchTo(epq->estate->es_query_cxt);
1990 slot = ExecProcNode(epq->planstate);
1991 MemoryContextSwitchTo(oldcontext);
1994 * No more tuples for this PQ. Continue previous one.
1996 if (TupIsNull(slot))
1998 evalPlanQual *oldepq;
2000 /* stop execution */
2001 EvalPlanQualStop(epq);
2002 /* pop old PQ from the stack */
2006 /* this is the first (oldest) PQ - mark as free */
2008 estate->es_useEvalPlan = false;
2009 /* and continue Query execution */
2012 Assert(oldepq->rti != 0);
2013 /* push current PQ to freePQ stack */
2016 estate->es_evalPlanQual = epq;
2024 EndEvalPlanQual(EState *estate)
2026 evalPlanQual *epq = estate->es_evalPlanQual;
2028 if (epq->rti == 0) /* plans already shutdowned */
2030 Assert(epq->next == NULL);
2036 evalPlanQual *oldepq;
2038 /* stop execution */
2039 EvalPlanQualStop(epq);
2040 /* pop old PQ from the stack */
2044 /* this is the first (oldest) PQ - mark as free */
2046 estate->es_useEvalPlan = false;
2049 Assert(oldepq->rti != 0);
2050 /* push current PQ to freePQ stack */
2053 estate->es_evalPlanQual = epq;
2058 * Start execution of one level of PlanQual.
2060 * This is a cut-down version of ExecutorStart(): we copy some state from
2061 * the top-level estate rather than initializing it fresh.
2064 EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
2068 MemoryContext oldcontext;
2070 rtsize = length(estate->es_range_table);
2072 epq->estate = epqstate = CreateExecutorState();
2074 oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2077 * The epqstates share the top query's copy of unchanging state such
2078 * as the snapshot, rangetable, result-rel info, and external Param
2079 * info. They need their own copies of local state, including a tuple
2080 * table, es_param_exec_vals, etc.
2082 epqstate->es_direction = ForwardScanDirection;
2083 epqstate->es_snapshot = estate->es_snapshot;
2084 epqstate->es_crosscheck_snapshot = estate->es_crosscheck_snapshot;
2085 epqstate->es_range_table = estate->es_range_table;
2086 epqstate->es_result_relations = estate->es_result_relations;
2087 epqstate->es_num_result_relations = estate->es_num_result_relations;
2088 epqstate->es_result_relation_info = estate->es_result_relation_info;
2089 epqstate->es_junkFilter = estate->es_junkFilter;
2090 epqstate->es_into_relation_descriptor = estate->es_into_relation_descriptor;
2091 epqstate->es_param_list_info = estate->es_param_list_info;
2092 if (estate->es_topPlan->nParamExec > 0)
2093 epqstate->es_param_exec_vals = (ParamExecData *)
2094 palloc0(estate->es_topPlan->nParamExec * sizeof(ParamExecData));
2095 epqstate->es_rowMark = estate->es_rowMark;
2096 epqstate->es_instrument = estate->es_instrument;
2097 epqstate->es_select_into = estate->es_select_into;
2098 epqstate->es_into_oids = estate->es_into_oids;
2099 epqstate->es_topPlan = estate->es_topPlan;
2102 * Each epqstate must have its own es_evTupleNull state, but all the
2103 * stack entries share es_evTuple state. This allows sub-rechecks to
2104 * inherit the value being examined by an outer recheck.
2106 epqstate->es_evTupleNull = (bool *) palloc0(rtsize * sizeof(bool));
2107 if (priorepq == NULL)
2108 /* first PQ stack entry */
2109 epqstate->es_evTuple = (HeapTuple *)
2110 palloc0(rtsize * sizeof(HeapTuple));
2112 /* later stack entries share the same storage */
2113 epqstate->es_evTuple = priorepq->estate->es_evTuple;
2115 epqstate->es_tupleTable =
2116 ExecCreateTupleTable(estate->es_tupleTable->size);
2118 epq->planstate = ExecInitNode(estate->es_topPlan, epqstate);
2120 MemoryContextSwitchTo(oldcontext);
2124 * End execution of one level of PlanQual.
2126 * This is a cut-down version of ExecutorEnd(); basically we want to do most
2127 * of the normal cleanup, but *not* close result relations (which we are
2128 * just sharing from the outer query).
2131 EvalPlanQualStop(evalPlanQual *epq)
2133 EState *epqstate = epq->estate;
2134 MemoryContext oldcontext;
2136 oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2138 ExecEndNode(epq->planstate);
2140 ExecDropTupleTable(epqstate->es_tupleTable, true);
2141 epqstate->es_tupleTable = NULL;
2143 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
2145 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
2146 epqstate->es_evTuple[epq->rti - 1] = NULL;
2149 MemoryContextSwitchTo(oldcontext);
2151 FreeExecutorState(epqstate);
2154 epq->planstate = NULL;