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11 * The old ExecutorMain() has been replaced by ExecutorStart(),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) 1996-2005, PostgreSQL Global Development Group
25 * Portions Copyright (c) 1994, Regents of the University of California
29 * $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.242 2005/03/16 21:38:06 tgl Exp $
31 *-------------------------------------------------------------------------
35 #include "access/heapam.h"
36 #include "catalog/heap.h"
37 #include "catalog/namespace.h"
38 #include "commands/tablecmds.h"
39 #include "commands/trigger.h"
40 #include "executor/execdebug.h"
41 #include "executor/execdefs.h"
42 #include "miscadmin.h"
43 #include "optimizer/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 explainOnly is true, we are not actually intending to run the plan,
110 * only to set up for EXPLAIN; so skip unwanted side-effects.
112 * NB: the CurrentMemoryContext when this is called will become the parent
113 * of the per-query context used for this Executor invocation.
114 * ----------------------------------------------------------------
117 ExecutorStart(QueryDesc *queryDesc, bool explainOnly)
120 MemoryContext oldcontext;
122 /* sanity checks: queryDesc must not be started already */
123 Assert(queryDesc != NULL);
124 Assert(queryDesc->estate == NULL);
127 * If the transaction is read-only, we need to check if any writes are
128 * planned to non-temporary tables.
130 if (XactReadOnly && !explainOnly)
131 ExecCheckXactReadOnly(queryDesc->parsetree);
134 * Build EState, switch into per-query memory context for startup.
136 estate = CreateExecutorState();
137 queryDesc->estate = estate;
139 oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
142 * Fill in parameters, if any, from queryDesc
144 estate->es_param_list_info = queryDesc->params;
146 if (queryDesc->plantree->nParamExec > 0)
147 estate->es_param_exec_vals = (ParamExecData *)
148 palloc0(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
151 * Copy other important information into the EState
153 estate->es_snapshot = queryDesc->snapshot;
154 estate->es_crosscheck_snapshot = queryDesc->crosscheck_snapshot;
155 estate->es_instrument = queryDesc->doInstrument;
158 * Initialize the plan state tree
160 InitPlan(queryDesc, explainOnly);
162 MemoryContextSwitchTo(oldcontext);
165 /* ----------------------------------------------------------------
168 * This is the main routine of the executor module. It accepts
169 * the query descriptor from the traffic cop and executes the
172 * ExecutorStart must have been called already.
174 * If direction is NoMovementScanDirection then nothing is done
175 * except to start up/shut down the destination. Otherwise,
176 * we retrieve up to 'count' tuples in the specified direction.
178 * Note: count = 0 is interpreted as no portal limit, i.e., run to
181 * ----------------------------------------------------------------
184 ExecutorRun(QueryDesc *queryDesc,
185 ScanDirection direction, long count)
190 TupleTableSlot *result;
191 MemoryContext oldcontext;
194 Assert(queryDesc != NULL);
196 estate = queryDesc->estate;
198 Assert(estate != NULL);
201 * Switch into per-query memory context
203 oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
206 * extract information from the query descriptor and the query
209 operation = queryDesc->operation;
210 dest = queryDesc->dest;
213 * startup tuple receiver
215 estate->es_processed = 0;
216 estate->es_lastoid = InvalidOid;
218 (*dest->rStartup) (dest, operation, queryDesc->tupDesc);
223 if (direction == NoMovementScanDirection)
226 result = ExecutePlan(estate,
227 queryDesc->planstate,
236 (*dest->rShutdown) (dest);
238 MemoryContextSwitchTo(oldcontext);
243 /* ----------------------------------------------------------------
246 * This routine must be called at the end of execution of any
248 * ----------------------------------------------------------------
251 ExecutorEnd(QueryDesc *queryDesc)
254 MemoryContext oldcontext;
257 Assert(queryDesc != NULL);
259 estate = queryDesc->estate;
261 Assert(estate != NULL);
264 * Switch into per-query memory context to run ExecEndPlan
266 oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
268 ExecEndPlan(queryDesc->planstate, estate);
271 * Must switch out of context before destroying it
273 MemoryContextSwitchTo(oldcontext);
276 * Release EState and per-query memory context. This should release
277 * everything the executor has allocated.
279 FreeExecutorState(estate);
281 /* Reset queryDesc fields that no longer point to anything */
282 queryDesc->tupDesc = NULL;
283 queryDesc->estate = NULL;
284 queryDesc->planstate = NULL;
287 /* ----------------------------------------------------------------
290 * This routine may be called on an open queryDesc to rewind it
292 * ----------------------------------------------------------------
295 ExecutorRewind(QueryDesc *queryDesc)
298 MemoryContext oldcontext;
301 Assert(queryDesc != NULL);
303 estate = queryDesc->estate;
305 Assert(estate != NULL);
307 /* It's probably not sensible to rescan updating queries */
308 Assert(queryDesc->operation == CMD_SELECT);
311 * Switch into per-query memory context
313 oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
318 ExecReScan(queryDesc->planstate, NULL);
320 MemoryContextSwitchTo(oldcontext);
326 * Check access permissions for all relations listed in a range table.
329 ExecCheckRTPerms(List *rangeTable)
333 foreach(l, rangeTable)
335 RangeTblEntry *rte = lfirst(l);
337 ExecCheckRTEPerms(rte);
343 * Check access permissions for a single RTE.
346 ExecCheckRTEPerms(RangeTblEntry *rte)
348 AclMode requiredPerms;
353 * If it's a subquery, recursively examine its rangetable.
355 if (rte->rtekind == RTE_SUBQUERY)
357 ExecCheckRTPerms(rte->subquery->rtable);
362 * Otherwise, only plain-relation RTEs need to be checked here.
363 * Function RTEs are checked by init_fcache when the function is
364 * prepared for execution. Join and special RTEs need no checks.
366 if (rte->rtekind != RTE_RELATION)
370 * No work if requiredPerms is empty.
372 requiredPerms = rte->requiredPerms;
373 if (requiredPerms == 0)
379 * userid to check as: current user unless we have a setuid
382 * Note: GetUserId() is presently fast enough that there's no harm in
383 * calling it separately for each RTE. If that stops being true, we
384 * could call it once in ExecCheckRTPerms and pass the userid down
385 * from there. But for now, no need for the extra clutter.
387 userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
390 * We must have *all* the requiredPerms bits, so use aclmask not
393 if (pg_class_aclmask(relOid, userid, requiredPerms, ACLMASK_ALL)
395 aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_CLASS,
396 get_rel_name(relOid));
400 * Check that the query does not imply any writes to non-temp tables.
403 ExecCheckXactReadOnly(Query *parsetree)
408 * CREATE TABLE AS or SELECT INTO?
410 * XXX should we allow this if the destination is temp?
412 if (parsetree->into != NULL)
415 /* Fail if write permissions are requested on any non-temp table */
416 foreach(l, parsetree->rtable)
418 RangeTblEntry *rte = lfirst(l);
420 if (rte->rtekind == RTE_SUBQUERY)
422 ExecCheckXactReadOnly(rte->subquery);
426 if (rte->rtekind != RTE_RELATION)
429 if ((rte->requiredPerms & (~ACL_SELECT)) == 0)
432 if (isTempNamespace(get_rel_namespace(rte->relid)))
442 (errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION),
443 errmsg("transaction is read-only")));
447 /* ----------------------------------------------------------------
450 * Initializes the query plan: open files, allocate storage
451 * and start up the rule manager
452 * ----------------------------------------------------------------
455 InitPlan(QueryDesc *queryDesc, bool explainOnly)
457 CmdType operation = queryDesc->operation;
458 Query *parseTree = queryDesc->parsetree;
459 Plan *plan = queryDesc->plantree;
460 EState *estate = queryDesc->estate;
461 PlanState *planstate;
463 Relation intoRelationDesc;
468 * Do permissions checks. It's sufficient to examine the query's top
469 * rangetable here --- subplan RTEs will be checked during
472 ExecCheckRTPerms(parseTree->rtable);
475 * get information from query descriptor
477 rangeTable = parseTree->rtable;
480 * initialize the node's execution state
482 estate->es_range_table = rangeTable;
485 * if there is a result relation, initialize result relation stuff
487 if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
489 List *resultRelations = parseTree->resultRelations;
490 int numResultRelations;
491 ResultRelInfo *resultRelInfos;
493 if (resultRelations != NIL)
496 * Multiple result relations (due to inheritance)
497 * parseTree->resultRelations identifies them all
499 ResultRelInfo *resultRelInfo;
502 numResultRelations = list_length(resultRelations);
503 resultRelInfos = (ResultRelInfo *)
504 palloc(numResultRelations * sizeof(ResultRelInfo));
505 resultRelInfo = resultRelInfos;
506 foreach(l, resultRelations)
508 initResultRelInfo(resultRelInfo,
518 * Single result relation identified by
519 * parseTree->resultRelation
521 numResultRelations = 1;
522 resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
523 initResultRelInfo(resultRelInfos,
524 parseTree->resultRelation,
529 estate->es_result_relations = resultRelInfos;
530 estate->es_num_result_relations = numResultRelations;
531 /* Initialize to first or only result rel */
532 estate->es_result_relation_info = resultRelInfos;
537 * if no result relation, then set state appropriately
539 estate->es_result_relations = NULL;
540 estate->es_num_result_relations = 0;
541 estate->es_result_relation_info = NULL;
545 * Detect whether we're doing SELECT INTO. If so, set the es_into_oids
546 * flag appropriately so that the plan tree will be initialized with
547 * the correct tuple descriptors.
549 do_select_into = false;
551 if (operation == CMD_SELECT && parseTree->into != NULL)
553 do_select_into = true;
554 estate->es_select_into = true;
555 estate->es_into_oids = parseTree->intoHasOids;
559 * Have to lock relations selected for update
561 estate->es_rowMark = NIL;
562 if (parseTree->rowMarks != NIL)
566 foreach(l, parseTree->rowMarks)
568 Index rti = lfirst_int(l);
569 Oid relid = getrelid(rti, rangeTable);
573 relation = heap_open(relid, RowShareLock);
574 erm = (execRowMark *) palloc(sizeof(execRowMark));
575 erm->relation = relation;
577 snprintf(erm->resname, sizeof(erm->resname), "ctid%u", rti);
578 estate->es_rowMark = lappend(estate->es_rowMark, erm);
583 * initialize the executor "tuple" table. We need slots for all the
584 * plan nodes, plus possibly output slots for the junkfilter(s). At
585 * this point we aren't sure if we need junkfilters, so just add slots
586 * for them unconditionally.
589 int nSlots = ExecCountSlotsNode(plan);
591 if (parseTree->resultRelations != NIL)
592 nSlots += list_length(parseTree->resultRelations);
595 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
598 /* mark EvalPlanQual not active */
599 estate->es_topPlan = plan;
600 estate->es_evalPlanQual = NULL;
601 estate->es_evTupleNull = NULL;
602 estate->es_evTuple = NULL;
603 estate->es_useEvalPlan = false;
606 * initialize the private state information for all the nodes in the
607 * query tree. This opens files, allocates storage and leaves us
608 * ready to start processing tuples.
610 planstate = ExecInitNode(plan, estate);
613 * Get the tuple descriptor describing the type of tuples to return.
614 * (this is especially important if we are creating a relation with
617 tupType = ExecGetResultType(planstate);
620 * Initialize the junk filter if needed. SELECT and INSERT queries
621 * need a filter if there are any junk attrs in the tlist. INSERT and
622 * SELECT INTO also need a filter if the plan may return raw disk
623 * tuples (else heap_insert will be scribbling on the source
624 * relation!). UPDATE and DELETE always need a filter, since there's
625 * always a junk 'ctid' attribute present --- no need to look first.
628 bool junk_filter_needed = false;
635 foreach(tlist, plan->targetlist)
637 TargetEntry *tle = (TargetEntry *) lfirst(tlist);
639 if (tle->resdom->resjunk)
641 junk_filter_needed = true;
645 if (!junk_filter_needed &&
646 (operation == CMD_INSERT || do_select_into) &&
647 ExecMayReturnRawTuples(planstate))
648 junk_filter_needed = true;
652 junk_filter_needed = true;
658 if (junk_filter_needed)
661 * If there are multiple result relations, each one needs its
662 * own junk filter. Note this is only possible for
663 * UPDATE/DELETE, so we can't be fooled by some needing a
664 * filter and some not.
666 if (parseTree->resultRelations != NIL)
668 PlanState **appendplans;
670 ResultRelInfo *resultRelInfo;
673 /* Top plan had better be an Append here. */
674 Assert(IsA(plan, Append));
675 Assert(((Append *) plan)->isTarget);
676 Assert(IsA(planstate, AppendState));
677 appendplans = ((AppendState *) planstate)->appendplans;
678 as_nplans = ((AppendState *) planstate)->as_nplans;
679 Assert(as_nplans == estate->es_num_result_relations);
680 resultRelInfo = estate->es_result_relations;
681 for (i = 0; i < as_nplans; i++)
683 PlanState *subplan = appendplans[i];
686 j = ExecInitJunkFilter(subplan->plan->targetlist,
687 resultRelInfo->ri_RelationDesc->rd_att->tdhasoid,
688 ExecAllocTableSlot(estate->es_tupleTable));
689 resultRelInfo->ri_junkFilter = j;
694 * Set active junkfilter too; at this point ExecInitAppend
695 * has already selected an active result relation...
697 estate->es_junkFilter =
698 estate->es_result_relation_info->ri_junkFilter;
702 /* Normal case with just one JunkFilter */
705 j = ExecInitJunkFilter(planstate->plan->targetlist,
707 ExecAllocTableSlot(estate->es_tupleTable));
708 estate->es_junkFilter = j;
709 if (estate->es_result_relation_info)
710 estate->es_result_relation_info->ri_junkFilter = j;
712 /* For SELECT, want to return the cleaned tuple type */
713 if (operation == CMD_SELECT)
714 tupType = j->jf_cleanTupType;
718 estate->es_junkFilter = NULL;
722 * If doing SELECT INTO, initialize the "into" relation. We must wait
723 * till now so we have the "clean" result tuple type to create the new
726 * If EXPLAIN, skip creating the "into" relation.
728 intoRelationDesc = NULL;
730 if (do_select_into && !explainOnly)
739 * find namespace to create in, check permissions
741 intoName = parseTree->into->relname;
742 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
744 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
746 if (aclresult != ACLCHECK_OK)
747 aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
748 get_namespace_name(namespaceId));
751 * have to copy tupType to get rid of constraints
753 tupdesc = CreateTupleDescCopy(tupType);
755 intoRelationId = heap_create_with_catalog(intoName,
764 allowSystemTableMods);
766 FreeTupleDesc(tupdesc);
769 * Advance command counter so that the newly-created relation's
770 * catalog tuples will be visible to heap_open.
772 CommandCounterIncrement();
775 * If necessary, create a TOAST table for the into relation. Note
776 * that AlterTableCreateToastTable ends with
777 * CommandCounterIncrement(), so that the TOAST table will be
778 * visible for insertion.
780 AlterTableCreateToastTable(intoRelationId, true);
783 * And open the constructed table for writing.
785 intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock);
788 estate->es_into_relation_descriptor = intoRelationDesc;
790 queryDesc->tupDesc = tupType;
791 queryDesc->planstate = planstate;
795 * Initialize ResultRelInfo data for one result relation
798 initResultRelInfo(ResultRelInfo *resultRelInfo,
799 Index resultRelationIndex,
803 Oid resultRelationOid;
804 Relation resultRelationDesc;
806 resultRelationOid = getrelid(resultRelationIndex, rangeTable);
807 resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
809 switch (resultRelationDesc->rd_rel->relkind)
811 case RELKIND_SEQUENCE:
813 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
814 errmsg("cannot change sequence \"%s\"",
815 RelationGetRelationName(resultRelationDesc))));
817 case RELKIND_TOASTVALUE:
819 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
820 errmsg("cannot change TOAST relation \"%s\"",
821 RelationGetRelationName(resultRelationDesc))));
825 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
826 errmsg("cannot change view \"%s\"",
827 RelationGetRelationName(resultRelationDesc))));
831 MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
832 resultRelInfo->type = T_ResultRelInfo;
833 resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
834 resultRelInfo->ri_RelationDesc = resultRelationDesc;
835 resultRelInfo->ri_NumIndices = 0;
836 resultRelInfo->ri_IndexRelationDescs = NULL;
837 resultRelInfo->ri_IndexRelationInfo = NULL;
838 /* make a copy so as not to depend on relcache info not changing... */
839 resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
840 resultRelInfo->ri_TrigFunctions = NULL;
841 resultRelInfo->ri_ConstraintExprs = NULL;
842 resultRelInfo->ri_junkFilter = NULL;
845 * If there are indices on the result relation, open them and save
846 * descriptors in the result relation info, so that we can add new
847 * index entries for the tuples we add/update. We need not do this
848 * for a DELETE, however, since deletion doesn't affect indexes.
850 if (resultRelationDesc->rd_rel->relhasindex &&
851 operation != CMD_DELETE)
852 ExecOpenIndices(resultRelInfo);
856 * ExecContextForcesOids
858 * This is pretty grotty: when doing INSERT, UPDATE, or SELECT INTO,
859 * we need to ensure that result tuples have space for an OID iff they are
860 * going to be stored into a relation that has OIDs. In other contexts
861 * we are free to choose whether to leave space for OIDs in result tuples
862 * (we generally don't want to, but we do if a physical-tlist optimization
863 * is possible). This routine checks the plan context and returns TRUE if the
864 * choice is forced, FALSE if the choice is not forced. In the TRUE case,
865 * *hasoids is set to the required value.
867 * One reason this is ugly is that all plan nodes in the plan tree will emit
868 * tuples with space for an OID, though we really only need the topmost node
869 * to do so. However, node types like Sort don't project new tuples but just
870 * return their inputs, and in those cases the requirement propagates down
871 * to the input node. Eventually we might make this code smart enough to
872 * recognize how far down the requirement really goes, but for now we just
873 * make all plan nodes do the same thing if the top level forces the choice.
875 * We assume that estate->es_result_relation_info is already set up to
876 * describe the target relation. Note that in an UPDATE that spans an
877 * inheritance tree, some of the target relations may have OIDs and some not.
878 * We have to make the decisions on a per-relation basis as we initialize
879 * each of the child plans of the topmost Append plan.
881 * SELECT INTO is even uglier, because we don't have the INTO relation's
882 * descriptor available when this code runs; we have to look aside at a
883 * flag set by InitPlan().
886 ExecContextForcesOids(PlanState *planstate, bool *hasoids)
888 if (planstate->state->es_select_into)
890 *hasoids = planstate->state->es_into_oids;
895 ResultRelInfo *ri = planstate->state->es_result_relation_info;
899 Relation rel = ri->ri_RelationDesc;
903 *hasoids = rel->rd_rel->relhasoids;
912 /* ----------------------------------------------------------------
915 * Cleans up the query plan -- closes files and frees up storage
917 * NOTE: we are no longer very worried about freeing storage per se
918 * in this code; FreeExecutorState should be guaranteed to release all
919 * memory that needs to be released. What we are worried about doing
920 * is closing relations and dropping buffer pins. Thus, for example,
921 * tuple tables must be cleared or dropped to ensure pins are released.
922 * ----------------------------------------------------------------
925 ExecEndPlan(PlanState *planstate, EState *estate)
927 ResultRelInfo *resultRelInfo;
932 * shut down any PlanQual processing we were doing
934 if (estate->es_evalPlanQual != NULL)
935 EndEvalPlanQual(estate);
938 * shut down the node-type-specific query processing
940 ExecEndNode(planstate);
943 * destroy the executor "tuple" table.
945 ExecDropTupleTable(estate->es_tupleTable, true);
946 estate->es_tupleTable = NULL;
949 * close the result relation(s) if any, but hold locks until xact
952 resultRelInfo = estate->es_result_relations;
953 for (i = estate->es_num_result_relations; i > 0; i--)
955 /* Close indices and then the relation itself */
956 ExecCloseIndices(resultRelInfo);
957 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
962 * close the "into" relation if necessary, again keeping lock
964 if (estate->es_into_relation_descriptor != NULL)
965 heap_close(estate->es_into_relation_descriptor, NoLock);
968 * close any relations selected FOR UPDATE, again keeping locks
970 foreach(l, estate->es_rowMark)
972 execRowMark *erm = lfirst(l);
974 heap_close(erm->relation, NoLock);
978 /* ----------------------------------------------------------------
981 * processes the query plan to retrieve 'numberTuples' tuples in the
982 * direction specified.
984 * Retrieves all tuples if numberTuples is 0
986 * result is either a slot containing the last tuple in the case
987 * of a SELECT or NULL otherwise.
989 * Note: the ctid attribute is a 'junk' attribute that is removed before the
991 * ----------------------------------------------------------------
993 static TupleTableSlot *
994 ExecutePlan(EState *estate,
995 PlanState *planstate,
998 ScanDirection direction,
1001 JunkFilter *junkfilter;
1002 TupleTableSlot *slot;
1003 ItemPointer tupleid = NULL;
1004 ItemPointerData tuple_ctid;
1005 long current_tuple_count;
1006 TupleTableSlot *result;
1009 * initialize local variables
1012 current_tuple_count = 0;
1016 * Set the direction.
1018 estate->es_direction = direction;
1021 * Process BEFORE EACH STATEMENT triggers
1026 ExecBSUpdateTriggers(estate, estate->es_result_relation_info);
1029 ExecBSDeleteTriggers(estate, estate->es_result_relation_info);
1032 ExecBSInsertTriggers(estate, estate->es_result_relation_info);
1040 * Loop until we've processed the proper number of tuples from the
1046 /* Reset the per-output-tuple exprcontext */
1047 ResetPerTupleExprContext(estate);
1050 * Execute the plan and obtain a tuple
1053 if (estate->es_useEvalPlan)
1055 slot = EvalPlanQualNext(estate);
1056 if (TupIsNull(slot))
1057 slot = ExecProcNode(planstate);
1060 slot = ExecProcNode(planstate);
1063 * if the tuple is null, then we assume there is nothing more to
1064 * process so we just return null...
1066 if (TupIsNull(slot))
1073 * if we have a junk filter, then project a new tuple with the
1076 * Store this new "clean" tuple in the junkfilter's resultSlot.
1077 * (Formerly, we stored it back over the "dirty" tuple, which is
1078 * WRONG because that tuple slot has the wrong descriptor.)
1080 * Also, extract all the junk information we need.
1082 if ((junkfilter = estate->es_junkFilter) != NULL)
1088 * extract the 'ctid' junk attribute.
1090 if (operation == CMD_UPDATE || operation == CMD_DELETE)
1092 if (!ExecGetJunkAttribute(junkfilter,
1097 elog(ERROR, "could not find junk ctid column");
1099 /* shouldn't ever get a null result... */
1101 elog(ERROR, "ctid is NULL");
1103 tupleid = (ItemPointer) DatumGetPointer(datum);
1104 tuple_ctid = *tupleid; /* make sure we don't free the
1106 tupleid = &tuple_ctid;
1108 else if (estate->es_rowMark != NIL)
1113 foreach(l, estate->es_rowMark)
1115 execRowMark *erm = lfirst(l);
1117 HeapTupleData tuple;
1118 TupleTableSlot *newSlot;
1121 if (!ExecGetJunkAttribute(junkfilter,
1126 elog(ERROR, "could not find junk \"%s\" column",
1129 /* shouldn't ever get a null result... */
1131 elog(ERROR, "\"%s\" is NULL", erm->resname);
1133 tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1134 test = heap_mark4update(erm->relation, &tuple, &buffer,
1135 estate->es_snapshot->curcid);
1136 ReleaseBuffer(buffer);
1139 case HeapTupleSelfUpdated:
1140 /* treat it as deleted; do not process */
1143 case HeapTupleMayBeUpdated:
1146 case HeapTupleUpdated:
1147 if (IsXactIsoLevelSerializable)
1149 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1150 errmsg("could not serialize access due to concurrent update")));
1151 if (!(ItemPointerEquals(&(tuple.t_self),
1152 (ItemPointer) DatumGetPointer(datum))))
1154 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1155 if (!(TupIsNull(newSlot)))
1158 estate->es_useEvalPlan = true;
1164 * if tuple was deleted or PlanQual failed for
1165 * updated tuple - we must not return this
1171 elog(ERROR, "unrecognized heap_mark4update status: %u",
1179 * Finally create a new "clean" tuple with all junk attributes
1182 slot = ExecFilterJunk(junkfilter, slot);
1186 * now that we have a tuple, do the appropriate thing with it..
1187 * either return it to the user, add it to a relation someplace,
1188 * delete it from a relation, or modify some of its attributes.
1193 ExecSelect(slot, /* slot containing tuple */
1194 dest, /* destination's tuple-receiver obj */
1200 ExecInsert(slot, tupleid, estate);
1205 ExecDelete(slot, tupleid, estate);
1210 ExecUpdate(slot, tupleid, estate);
1215 elog(ERROR, "unrecognized operation code: %d",
1222 * check our tuple count.. if we've processed the proper number
1223 * then quit, else loop again and process more tuples. Zero
1224 * numberTuples means no limit.
1226 current_tuple_count++;
1227 if (numberTuples && numberTuples == current_tuple_count)
1232 * Process AFTER EACH STATEMENT triggers
1237 ExecASUpdateTriggers(estate, estate->es_result_relation_info);
1240 ExecASDeleteTriggers(estate, estate->es_result_relation_info);
1243 ExecASInsertTriggers(estate, estate->es_result_relation_info);
1251 * here, result is either a slot containing a tuple in the case of a
1252 * SELECT or NULL otherwise.
1257 /* ----------------------------------------------------------------
1260 * SELECTs are easy.. we just pass the tuple to the appropriate
1261 * print function. The only complexity is when we do a
1262 * "SELECT INTO", in which case we insert the tuple into
1263 * the appropriate relation (note: this is a newly created relation
1264 * so we don't need to worry about indices or locks.)
1265 * ----------------------------------------------------------------
1268 ExecSelect(TupleTableSlot *slot,
1273 * insert the tuple into the "into relation"
1275 * XXX this probably ought to be replaced by a separate destination
1277 if (estate->es_into_relation_descriptor != NULL)
1281 tuple = ExecCopySlotTuple(slot);
1282 heap_insert(estate->es_into_relation_descriptor, tuple,
1283 estate->es_snapshot->curcid);
1284 /* we know there are no indexes to update */
1285 heap_freetuple(tuple);
1290 * send the tuple to the destination
1292 (*dest->receiveSlot) (slot, dest);
1294 (estate->es_processed)++;
1297 /* ----------------------------------------------------------------
1300 * INSERTs are trickier.. we have to insert the tuple into
1301 * the base relation and insert appropriate tuples into the
1303 * ----------------------------------------------------------------
1306 ExecInsert(TupleTableSlot *slot,
1307 ItemPointer tupleid,
1311 ResultRelInfo *resultRelInfo;
1312 Relation resultRelationDesc;
1317 * get the heap tuple out of the tuple table slot, making sure
1318 * we have a writable copy
1320 tuple = ExecMaterializeSlot(slot);
1323 * get information on the (current) result relation
1325 resultRelInfo = estate->es_result_relation_info;
1326 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1328 /* BEFORE ROW INSERT Triggers */
1329 if (resultRelInfo->ri_TrigDesc &&
1330 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1334 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1336 if (newtuple == NULL) /* "do nothing" */
1339 if (newtuple != tuple) /* modified by Trigger(s) */
1342 * Insert modified tuple into tuple table slot, replacing the
1343 * original. We assume that it was allocated in per-tuple
1344 * memory context, and therefore will go away by itself. The
1345 * tuple table slot should not try to clear it.
1347 ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1353 * Check the constraints of the tuple
1355 if (resultRelationDesc->rd_att->constr)
1356 ExecConstraints(resultRelInfo, slot, estate);
1361 newId = heap_insert(resultRelationDesc, tuple,
1362 estate->es_snapshot->curcid);
1365 (estate->es_processed)++;
1366 estate->es_lastoid = newId;
1367 setLastTid(&(tuple->t_self));
1372 * Note: heap_insert adds a new tuple to a relation. As a side effect,
1373 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1376 numIndices = resultRelInfo->ri_NumIndices;
1378 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1380 /* AFTER ROW INSERT Triggers */
1381 ExecARInsertTriggers(estate, resultRelInfo, tuple);
1384 /* ----------------------------------------------------------------
1387 * DELETE is like UPDATE, we delete the tuple and its
1389 * ----------------------------------------------------------------
1392 ExecDelete(TupleTableSlot *slot,
1393 ItemPointer tupleid,
1396 ResultRelInfo *resultRelInfo;
1397 Relation resultRelationDesc;
1398 ItemPointerData ctid;
1402 * get information on the (current) result relation
1404 resultRelInfo = estate->es_result_relation_info;
1405 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1407 /* BEFORE ROW DELETE Triggers */
1408 if (resultRelInfo->ri_TrigDesc &&
1409 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1413 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid,
1414 estate->es_snapshot->curcid);
1416 if (!dodelete) /* "do nothing" */
1423 * Note: if es_crosscheck_snapshot isn't InvalidSnapshot, we check that
1424 * the row to be deleted is visible to that snapshot, and throw a can't-
1425 * serialize error if not. This is a special-case behavior needed for
1426 * referential integrity updates in serializable transactions.
1429 result = heap_delete(resultRelationDesc, tupleid,
1431 estate->es_snapshot->curcid,
1432 estate->es_crosscheck_snapshot,
1433 true /* wait for commit */ );
1436 case HeapTupleSelfUpdated:
1437 /* already deleted by self; nothing to do */
1440 case HeapTupleMayBeUpdated:
1443 case HeapTupleUpdated:
1444 if (IsXactIsoLevelSerializable)
1446 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1447 errmsg("could not serialize access due to concurrent update")));
1448 else if (!(ItemPointerEquals(tupleid, &ctid)))
1450 TupleTableSlot *epqslot = EvalPlanQual(estate,
1451 resultRelInfo->ri_RangeTableIndex, &ctid);
1453 if (!TupIsNull(epqslot))
1459 /* tuple already deleted; nothing to do */
1463 elog(ERROR, "unrecognized heap_delete status: %u", result);
1468 (estate->es_processed)++;
1471 * Note: Normally one would think that we have to delete index tuples
1472 * associated with the heap tuple now..
1474 * ... but in POSTGRES, we have no need to do this because the vacuum
1475 * daemon automatically opens an index scan and deletes index tuples
1476 * when it finds deleted heap tuples. -cim 9/27/89
1479 /* AFTER ROW DELETE Triggers */
1480 ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1483 /* ----------------------------------------------------------------
1486 * note: we can't run UPDATE queries with transactions
1487 * off because UPDATEs are actually INSERTs and our
1488 * scan will mistakenly loop forever, updating the tuple
1489 * it just inserted.. This should be fixed but until it
1490 * is, we don't want to get stuck in an infinite loop
1491 * which corrupts your database..
1492 * ----------------------------------------------------------------
1495 ExecUpdate(TupleTableSlot *slot,
1496 ItemPointer tupleid,
1500 ResultRelInfo *resultRelInfo;
1501 Relation resultRelationDesc;
1502 ItemPointerData ctid;
1507 * abort the operation if not running transactions
1509 if (IsBootstrapProcessingMode())
1510 elog(ERROR, "cannot UPDATE during bootstrap");
1513 * get the heap tuple out of the tuple table slot, making sure
1514 * we have a writable copy
1516 tuple = ExecMaterializeSlot(slot);
1519 * get information on the (current) result relation
1521 resultRelInfo = estate->es_result_relation_info;
1522 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1524 /* BEFORE ROW UPDATE Triggers */
1525 if (resultRelInfo->ri_TrigDesc &&
1526 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1530 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1532 estate->es_snapshot->curcid);
1534 if (newtuple == NULL) /* "do nothing" */
1537 if (newtuple != tuple) /* modified by Trigger(s) */
1540 * Insert modified tuple into tuple table slot, replacing the
1541 * original. We assume that it was allocated in per-tuple
1542 * memory context, and therefore will go away by itself. The
1543 * tuple table slot should not try to clear it.
1545 ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1551 * Check the constraints of the tuple
1553 * If we generate a new candidate tuple after EvalPlanQual testing, we
1554 * must loop back here and recheck constraints. (We don't need to
1555 * redo triggers, however. If there are any BEFORE triggers then
1556 * trigger.c will have done mark4update to lock the correct tuple, so
1557 * there's no need to do them again.)
1560 if (resultRelationDesc->rd_att->constr)
1561 ExecConstraints(resultRelInfo, slot, estate);
1564 * replace the heap tuple
1566 * Note: if es_crosscheck_snapshot isn't InvalidSnapshot, we check that
1567 * the row to be updated is visible to that snapshot, and throw a can't-
1568 * serialize error if not. This is a special-case behavior needed for
1569 * referential integrity updates in serializable transactions.
1571 result = heap_update(resultRelationDesc, tupleid, tuple,
1573 estate->es_snapshot->curcid,
1574 estate->es_crosscheck_snapshot,
1575 true /* wait for commit */ );
1578 case HeapTupleSelfUpdated:
1579 /* already deleted by self; nothing to do */
1582 case HeapTupleMayBeUpdated:
1585 case HeapTupleUpdated:
1586 if (IsXactIsoLevelSerializable)
1588 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1589 errmsg("could not serialize access due to concurrent update")));
1590 else if (!(ItemPointerEquals(tupleid, &ctid)))
1592 TupleTableSlot *epqslot = EvalPlanQual(estate,
1593 resultRelInfo->ri_RangeTableIndex, &ctid);
1595 if (!TupIsNull(epqslot))
1598 slot = ExecFilterJunk(estate->es_junkFilter, epqslot);
1599 tuple = ExecMaterializeSlot(slot);
1603 /* tuple already deleted; nothing to do */
1607 elog(ERROR, "unrecognized heap_update status: %u", result);
1612 (estate->es_processed)++;
1615 * Note: instead of having to update the old index tuples associated
1616 * with the heap tuple, all we do is form and insert new index tuples.
1617 * This is because UPDATEs are actually DELETEs and INSERTs and index
1618 * tuple deletion is done automagically by the vacuum daemon. All we
1619 * do is insert new index tuples. -cim 9/27/89
1625 * heap_update updates a tuple in the base relation by invalidating it
1626 * and then inserting a new tuple to the relation. As a side effect,
1627 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1628 * field. So we now insert index tuples using the new tupleid stored
1632 numIndices = resultRelInfo->ri_NumIndices;
1634 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1636 /* AFTER ROW UPDATE Triggers */
1637 ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1641 ExecRelCheck(ResultRelInfo *resultRelInfo,
1642 TupleTableSlot *slot, EState *estate)
1644 Relation rel = resultRelInfo->ri_RelationDesc;
1645 int ncheck = rel->rd_att->constr->num_check;
1646 ConstrCheck *check = rel->rd_att->constr->check;
1647 ExprContext *econtext;
1648 MemoryContext oldContext;
1653 * If first time through for this result relation, build expression
1654 * nodetrees for rel's constraint expressions. Keep them in the
1655 * per-query memory context so they'll survive throughout the query.
1657 if (resultRelInfo->ri_ConstraintExprs == NULL)
1659 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1660 resultRelInfo->ri_ConstraintExprs =
1661 (List **) palloc(ncheck * sizeof(List *));
1662 for (i = 0; i < ncheck; i++)
1664 /* ExecQual wants implicit-AND form */
1665 qual = make_ands_implicit(stringToNode(check[i].ccbin));
1666 resultRelInfo->ri_ConstraintExprs[i] = (List *)
1667 ExecPrepareExpr((Expr *) qual, estate);
1669 MemoryContextSwitchTo(oldContext);
1673 * We will use the EState's per-tuple context for evaluating
1674 * constraint expressions (creating it if it's not already there).
1676 econtext = GetPerTupleExprContext(estate);
1678 /* Arrange for econtext's scan tuple to be the tuple under test */
1679 econtext->ecxt_scantuple = slot;
1681 /* And evaluate the constraints */
1682 for (i = 0; i < ncheck; i++)
1684 qual = resultRelInfo->ri_ConstraintExprs[i];
1687 * NOTE: SQL92 specifies that a NULL result from a constraint
1688 * expression is not to be treated as a failure. Therefore, tell
1689 * ExecQual to return TRUE for NULL.
1691 if (!ExecQual(qual, econtext, true))
1692 return check[i].ccname;
1695 /* NULL result means no error */
1700 ExecConstraints(ResultRelInfo *resultRelInfo,
1701 TupleTableSlot *slot, EState *estate)
1703 Relation rel = resultRelInfo->ri_RelationDesc;
1704 TupleConstr *constr = rel->rd_att->constr;
1708 if (constr->has_not_null)
1710 int natts = rel->rd_att->natts;
1713 for (attrChk = 1; attrChk <= natts; attrChk++)
1715 if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1716 slot_attisnull(slot, attrChk))
1718 (errcode(ERRCODE_NOT_NULL_VIOLATION),
1719 errmsg("null value in column \"%s\" violates not-null constraint",
1720 NameStr(rel->rd_att->attrs[attrChk - 1]->attname))));
1724 if (constr->num_check > 0)
1728 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1730 (errcode(ERRCODE_CHECK_VIOLATION),
1731 errmsg("new row for relation \"%s\" violates check constraint \"%s\"",
1732 RelationGetRelationName(rel), failed)));
1737 * Check a modified tuple to see if we want to process its updated version
1738 * under READ COMMITTED rules.
1740 * See backend/executor/README for some info about how this works.
1743 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1748 HeapTupleData tuple;
1749 HeapTuple copyTuple = NULL;
1755 * find relation containing target tuple
1757 if (estate->es_result_relation_info != NULL &&
1758 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1759 relation = estate->es_result_relation_info->ri_RelationDesc;
1765 foreach(l, estate->es_rowMark)
1767 if (((execRowMark *) lfirst(l))->rti == rti)
1769 relation = ((execRowMark *) lfirst(l))->relation;
1773 if (relation == NULL)
1774 elog(ERROR, "could not find RowMark for RT index %u", rti);
1780 * Loop here to deal with updated or busy tuples
1782 tuple.t_self = *tid;
1787 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1789 TransactionId xwait = SnapshotDirty->xmax;
1791 /* xmin should not be dirty... */
1792 if (TransactionIdIsValid(SnapshotDirty->xmin))
1793 elog(ERROR, "t_xmin is uncommitted in tuple to be updated");
1796 * If tuple is being updated by other transaction then we have
1797 * to wait for its commit/abort.
1799 if (TransactionIdIsValid(xwait))
1801 ReleaseBuffer(buffer);
1802 XactLockTableWait(xwait);
1807 * We got tuple - now copy it for use by recheck query.
1809 copyTuple = heap_copytuple(&tuple);
1810 ReleaseBuffer(buffer);
1815 * Oops! Invalid tuple. Have to check is it updated or deleted.
1816 * Note that it's possible to get invalid SnapshotDirty->tid if
1817 * tuple updated by this transaction. Have we to check this ?
1819 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1820 !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1822 /* updated, so look at the updated copy */
1823 tuple.t_self = SnapshotDirty->tid;
1828 * Deleted or updated by this transaction; forget it.
1834 * For UPDATE/DELETE we have to return tid of actual row we're
1837 *tid = tuple.t_self;
1840 * Need to run a recheck subquery. Find or create a PQ stack entry.
1842 epq = estate->es_evalPlanQual;
1845 if (epq != NULL && epq->rti == 0)
1847 /* Top PQ stack entry is idle, so re-use it */
1848 Assert(!(estate->es_useEvalPlan) && epq->next == NULL);
1854 * If this is request for another RTE - Ra, - then we have to check
1855 * wasn't PlanQual requested for Ra already and if so then Ra' row was
1856 * updated again and we have to re-start old execution for Ra and
1857 * forget all what we done after Ra was suspended. Cool? -:))
1859 if (epq != NULL && epq->rti != rti &&
1860 epq->estate->es_evTuple[rti - 1] != NULL)
1864 evalPlanQual *oldepq;
1866 /* stop execution */
1867 EvalPlanQualStop(epq);
1868 /* pop previous PlanQual from the stack */
1870 Assert(oldepq && oldepq->rti != 0);
1871 /* push current PQ to freePQ stack */
1874 estate->es_evalPlanQual = epq;
1875 } while (epq->rti != rti);
1879 * If we are requested for another RTE then we have to suspend
1880 * execution of current PlanQual and start execution for new one.
1882 if (epq == NULL || epq->rti != rti)
1884 /* try to reuse plan used previously */
1885 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1887 if (newepq == NULL) /* first call or freePQ stack is empty */
1889 newepq = (evalPlanQual *) palloc0(sizeof(evalPlanQual));
1890 newepq->free = NULL;
1891 newepq->estate = NULL;
1892 newepq->planstate = NULL;
1896 /* recycle previously used PlanQual */
1897 Assert(newepq->estate == NULL);
1900 /* push current PQ to the stack */
1903 estate->es_evalPlanQual = epq;
1908 Assert(epq->rti == rti);
1911 * Ok - we're requested for the same RTE. Unfortunately we still have
1912 * to end and restart execution of the plan, because ExecReScan
1913 * wouldn't ensure that upper plan nodes would reset themselves. We
1914 * could make that work if insertion of the target tuple were
1915 * integrated with the Param mechanism somehow, so that the upper plan
1916 * nodes know that their children's outputs have changed.
1918 * Note that the stack of free evalPlanQual nodes is quite useless at the
1919 * moment, since it only saves us from pallocing/releasing the
1920 * evalPlanQual nodes themselves. But it will be useful once we
1921 * implement ReScan instead of end/restart for re-using PlanQual
1926 /* stop execution */
1927 EvalPlanQualStop(epq);
1931 * Initialize new recheck query.
1933 * Note: if we were re-using PlanQual plans via ExecReScan, we'd need to
1934 * instead copy down changeable state from the top plan (including
1935 * es_result_relation_info, es_junkFilter) and reset locally
1936 * changeable state in the epq (including es_param_exec_vals,
1939 EvalPlanQualStart(epq, estate, epq->next);
1942 * free old RTE' tuple, if any, and store target tuple where
1943 * relation's scan node will see it
1945 epqstate = epq->estate;
1946 if (epqstate->es_evTuple[rti - 1] != NULL)
1947 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1948 epqstate->es_evTuple[rti - 1] = copyTuple;
1950 return EvalPlanQualNext(estate);
1953 static TupleTableSlot *
1954 EvalPlanQualNext(EState *estate)
1956 evalPlanQual *epq = estate->es_evalPlanQual;
1957 MemoryContext oldcontext;
1958 TupleTableSlot *slot;
1960 Assert(epq->rti != 0);
1963 oldcontext = MemoryContextSwitchTo(epq->estate->es_query_cxt);
1964 slot = ExecProcNode(epq->planstate);
1965 MemoryContextSwitchTo(oldcontext);
1968 * No more tuples for this PQ. Continue previous one.
1970 if (TupIsNull(slot))
1972 evalPlanQual *oldepq;
1974 /* stop execution */
1975 EvalPlanQualStop(epq);
1976 /* pop old PQ from the stack */
1980 /* this is the first (oldest) PQ - mark as free */
1982 estate->es_useEvalPlan = false;
1983 /* and continue Query execution */
1986 Assert(oldepq->rti != 0);
1987 /* push current PQ to freePQ stack */
1990 estate->es_evalPlanQual = epq;
1998 EndEvalPlanQual(EState *estate)
2000 evalPlanQual *epq = estate->es_evalPlanQual;
2002 if (epq->rti == 0) /* plans already shutdowned */
2004 Assert(epq->next == NULL);
2010 evalPlanQual *oldepq;
2012 /* stop execution */
2013 EvalPlanQualStop(epq);
2014 /* pop old PQ from the stack */
2018 /* this is the first (oldest) PQ - mark as free */
2020 estate->es_useEvalPlan = false;
2023 Assert(oldepq->rti != 0);
2024 /* push current PQ to freePQ stack */
2027 estate->es_evalPlanQual = epq;
2032 * Start execution of one level of PlanQual.
2034 * This is a cut-down version of ExecutorStart(): we copy some state from
2035 * the top-level estate rather than initializing it fresh.
2038 EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
2042 MemoryContext oldcontext;
2044 rtsize = list_length(estate->es_range_table);
2046 epq->estate = epqstate = CreateExecutorState();
2048 oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2051 * The epqstates share the top query's copy of unchanging state such
2052 * as the snapshot, rangetable, result-rel info, and external Param
2053 * info. They need their own copies of local state, including a tuple
2054 * table, es_param_exec_vals, etc.
2056 epqstate->es_direction = ForwardScanDirection;
2057 epqstate->es_snapshot = estate->es_snapshot;
2058 epqstate->es_crosscheck_snapshot = estate->es_crosscheck_snapshot;
2059 epqstate->es_range_table = estate->es_range_table;
2060 epqstate->es_result_relations = estate->es_result_relations;
2061 epqstate->es_num_result_relations = estate->es_num_result_relations;
2062 epqstate->es_result_relation_info = estate->es_result_relation_info;
2063 epqstate->es_junkFilter = estate->es_junkFilter;
2064 epqstate->es_into_relation_descriptor = estate->es_into_relation_descriptor;
2065 epqstate->es_param_list_info = estate->es_param_list_info;
2066 if (estate->es_topPlan->nParamExec > 0)
2067 epqstate->es_param_exec_vals = (ParamExecData *)
2068 palloc0(estate->es_topPlan->nParamExec * sizeof(ParamExecData));
2069 epqstate->es_rowMark = estate->es_rowMark;
2070 epqstate->es_instrument = estate->es_instrument;
2071 epqstate->es_select_into = estate->es_select_into;
2072 epqstate->es_into_oids = estate->es_into_oids;
2073 epqstate->es_topPlan = estate->es_topPlan;
2076 * Each epqstate must have its own es_evTupleNull state, but all the
2077 * stack entries share es_evTuple state. This allows sub-rechecks to
2078 * inherit the value being examined by an outer recheck.
2080 epqstate->es_evTupleNull = (bool *) palloc0(rtsize * sizeof(bool));
2081 if (priorepq == NULL)
2082 /* first PQ stack entry */
2083 epqstate->es_evTuple = (HeapTuple *)
2084 palloc0(rtsize * sizeof(HeapTuple));
2086 /* later stack entries share the same storage */
2087 epqstate->es_evTuple = priorepq->estate->es_evTuple;
2089 epqstate->es_tupleTable =
2090 ExecCreateTupleTable(estate->es_tupleTable->size);
2092 epq->planstate = ExecInitNode(estate->es_topPlan, epqstate);
2094 MemoryContextSwitchTo(oldcontext);
2098 * End execution of one level of PlanQual.
2100 * This is a cut-down version of ExecutorEnd(); basically we want to do most
2101 * of the normal cleanup, but *not* close result relations (which we are
2102 * just sharing from the outer query).
2105 EvalPlanQualStop(evalPlanQual *epq)
2107 EState *epqstate = epq->estate;
2108 MemoryContext oldcontext;
2110 oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2112 ExecEndNode(epq->planstate);
2114 ExecDropTupleTable(epqstate->es_tupleTable, true);
2115 epqstate->es_tupleTable = NULL;
2117 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
2119 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
2120 epqstate->es_evTuple[epq->rti - 1] = NULL;
2123 MemoryContextSwitchTo(oldcontext);
2125 FreeExecutorState(epqstate);
2128 epq->planstate = NULL;