1 /*-------------------------------------------------------------------------
4 * top level executor interface routines
11 * The old ExecutorMain() has been replaced by ExecutorStart(),
12 * ExecutorRun() and ExecutorEnd()
14 * These three procedures are the external interfaces to the executor.
15 * In each case, the query descriptor and the execution state is required
18 * ExecutorStart() must be called at the beginning of any execution of any
19 * query plan and ExecutorEnd() should always be called at the end of
20 * execution of a plan.
22 * ExecutorRun accepts direction and count arguments that specify whether
23 * the plan is to be executed forwards, backwards, and for how many tuples.
25 * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
26 * Portions Copyright (c) 1994, Regents of the University of California
30 * $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.176 2002/08/29 00:17:03 tgl Exp $
32 *-------------------------------------------------------------------------
36 #include "access/heapam.h"
37 #include "catalog/heap.h"
38 #include "catalog/namespace.h"
39 #include "commands/tablecmds.h"
40 #include "commands/trigger.h"
41 #include "executor/execdebug.h"
42 #include "executor/execdefs.h"
43 #include "miscadmin.h"
44 #include "optimizer/var.h"
45 #include "parser/parsetree.h"
46 #include "utils/acl.h"
47 #include "utils/lsyscache.h"
50 /* decls for local routines only used within this module */
51 static TupleDesc InitPlan(CmdType operation,
55 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
56 Index resultRelationIndex,
59 static void EndPlan(Plan *plan, EState *estate);
60 static TupleTableSlot *ExecutePlan(EState *estate, Plan *plan,
63 ScanDirection direction,
64 DestReceiver *destfunc);
65 static void ExecSelect(TupleTableSlot *slot,
66 DestReceiver *destfunc,
68 static void ExecInsert(TupleTableSlot *slot, ItemPointer tupleid,
70 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
72 static void ExecUpdate(TupleTableSlot *slot, ItemPointer tupleid,
74 static TupleTableSlot *EvalPlanQualNext(EState *estate);
75 static void EndEvalPlanQual(EState *estate);
76 static void ExecCheckQueryPerms(CmdType operation, Query *parseTree,
78 static void ExecCheckPlanPerms(Plan *plan, List *rangeTable,
80 static void ExecCheckRTPerms(List *rangeTable, CmdType operation);
81 static void ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation);
83 /* end of local decls */
86 /* ----------------------------------------------------------------
89 * This routine must be called at the beginning of any execution of any
92 * returns a TupleDesc which describes the attributes of the tuples to
93 * be returned by the query. (Same value is saved in queryDesc)
95 * NB: the CurrentMemoryContext when this is called must be the context
96 * to be used as the per-query context for the query plan. ExecutorRun()
97 * and ExecutorEnd() must be called in this same memory context.
98 * ----------------------------------------------------------------
101 ExecutorStart(QueryDesc *queryDesc, EState *estate)
106 Assert(queryDesc != NULL);
108 if (queryDesc->plantree->nParamExec > 0)
110 estate->es_param_exec_vals = (ParamExecData *)
111 palloc(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
112 MemSet(estate->es_param_exec_vals, 0,
113 queryDesc->plantree->nParamExec * sizeof(ParamExecData));
117 * Make our own private copy of the current query snapshot data.
119 * This "freezes" our idea of which tuples are good and which are not
120 * for the life of this query, even if it outlives the current command
121 * and current snapshot.
123 estate->es_snapshot = CopyQuerySnapshot();
126 * Initialize the plan
128 result = InitPlan(queryDesc->operation,
129 queryDesc->parsetree,
133 queryDesc->tupDesc = result;
138 /* ----------------------------------------------------------------
141 * This is the main routine of the executor module. It accepts
142 * the query descriptor from the traffic cop and executes the
145 * ExecutorStart must have been called already.
147 * If direction is NoMovementScanDirection then nothing is done
148 * except to start up/shut down the destination. Otherwise,
149 * we retrieve up to 'count' tuples in the specified direction.
151 * Note: count = 0 is interpreted as no portal limit, e.g. run to
154 * ----------------------------------------------------------------
157 ExecutorRun(QueryDesc *queryDesc, EState *estate,
158 ScanDirection direction, long count)
163 DestReceiver *destfunc;
164 TupleTableSlot *result;
169 Assert(queryDesc != NULL);
172 * extract information from the query descriptor and the query
175 operation = queryDesc->operation;
176 plan = queryDesc->plantree;
177 dest = queryDesc->dest;
180 * startup tuple receiver
182 estate->es_processed = 0;
183 estate->es_lastoid = InvalidOid;
185 destfunc = DestToFunction(dest);
186 (*destfunc->setup) (destfunc, (int) operation,
187 queryDesc->portalName, queryDesc->tupDesc);
192 if (direction == NoMovementScanDirection)
195 result = ExecutePlan(estate,
205 (*destfunc->cleanup) (destfunc);
210 /* ----------------------------------------------------------------
213 * This routine must be called at the end of execution of any
215 * ----------------------------------------------------------------
218 ExecutorEnd(QueryDesc *queryDesc, EState *estate)
221 Assert(queryDesc != NULL);
223 EndPlan(queryDesc->plantree, estate);
225 if (estate->es_snapshot != NULL)
227 if (estate->es_snapshot->xcnt > 0)
228 pfree(estate->es_snapshot->xip);
229 pfree(estate->es_snapshot);
230 estate->es_snapshot = NULL;
233 if (estate->es_param_exec_vals != NULL)
235 pfree(estate->es_param_exec_vals);
236 estate->es_param_exec_vals = NULL;
242 * ExecCheckQueryPerms
243 * Check access permissions for all relations referenced in a query.
246 ExecCheckQueryPerms(CmdType operation, Query *parseTree, Plan *plan)
249 * Check RTEs in the query's primary rangetable.
251 ExecCheckRTPerms(parseTree->rtable, operation);
254 * Search for subplans and APPEND nodes to check their rangetables.
256 ExecCheckPlanPerms(plan, parseTree->rtable, operation);
261 * Recursively scan the plan tree to check access permissions in
265 ExecCheckPlanPerms(Plan *plan, List *rangeTable, CmdType operation)
272 /* Check subplans, which we assume are plain SELECT queries */
274 foreach(subp, plan->initPlan)
276 SubPlan *subplan = (SubPlan *) lfirst(subp);
278 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
279 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
281 foreach(subp, plan->subPlan)
283 SubPlan *subplan = (SubPlan *) lfirst(subp);
285 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
286 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
289 /* Check lower plan nodes */
291 ExecCheckPlanPerms(plan->lefttree, rangeTable, operation);
292 ExecCheckPlanPerms(plan->righttree, rangeTable, operation);
294 /* Do node-type-specific checks */
296 switch (nodeTag(plan))
300 SubqueryScan *scan = (SubqueryScan *) plan;
303 /* Recursively check the subquery */
304 rte = rt_fetch(scan->scan.scanrelid, rangeTable);
305 Assert(rte->rtekind == RTE_SUBQUERY);
306 ExecCheckQueryPerms(operation, rte->subquery, scan->subplan);
311 Append *app = (Append *) plan;
314 foreach(appendplans, app->appendplans)
316 ExecCheckPlanPerms((Plan *) lfirst(appendplans),
330 * Check access permissions for all relations listed in a range table.
333 ExecCheckRTPerms(List *rangeTable, CmdType operation)
337 foreach(lp, rangeTable)
339 RangeTblEntry *rte = lfirst(lp);
341 ExecCheckRTEPerms(rte, operation);
347 * Check access permissions for a single RTE.
350 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
354 AclResult aclcheck_result;
357 * Only plain-relation RTEs need to be checked here. Subquery RTEs
358 * will be checked when ExecCheckPlanPerms finds the SubqueryScan node,
359 * and function RTEs are checked by init_fcache when the function is
360 * prepared for execution. Join and special RTEs need no checks.
362 if (rte->rtekind != RTE_RELATION)
368 * userid to check as: current user unless we have a setuid
371 * Note: GetUserId() is presently fast enough that there's no harm in
372 * calling it separately for each RTE. If that stops being true, we
373 * could call it once in ExecCheckQueryPerms and pass the userid down
374 * from there. But for now, no need for the extra clutter.
376 userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
378 #define CHECK(MODE) pg_class_aclcheck(relOid, userid, MODE)
380 if (rte->checkForRead)
382 aclcheck_result = CHECK(ACL_SELECT);
383 if (aclcheck_result != ACLCHECK_OK)
384 aclcheck_error(aclcheck_result, get_rel_name(relOid));
387 if (rte->checkForWrite)
390 * Note: write access in a SELECT context means SELECT FOR UPDATE.
391 * Right now we don't distinguish that from true update as far as
392 * permissions checks are concerned.
397 aclcheck_result = CHECK(ACL_INSERT);
401 aclcheck_result = CHECK(ACL_UPDATE);
404 aclcheck_result = CHECK(ACL_DELETE);
407 elog(ERROR, "ExecCheckRTEPerms: bogus operation %d",
409 aclcheck_result = ACLCHECK_OK; /* keep compiler quiet */
412 if (aclcheck_result != ACLCHECK_OK)
413 aclcheck_error(aclcheck_result, get_rel_name(relOid));
418 /* ===============================================================
419 * ===============================================================
420 static routines follow
421 * ===============================================================
422 * ===============================================================
425 typedef struct execRowMark
432 typedef struct evalPlanQual
437 struct evalPlanQual *free;
440 /* ----------------------------------------------------------------
443 * Initializes the query plan: open files, allocate storage
444 * and start up the rule manager
445 * ----------------------------------------------------------------
448 InitPlan(CmdType operation, Query *parseTree, Plan *plan, EState *estate)
451 Relation intoRelationDesc;
455 * Do permissions checks.
457 ExecCheckQueryPerms(operation, parseTree, plan);
460 * get information from query descriptor
462 rangeTable = parseTree->rtable;
465 * initialize the node's execution state
467 estate->es_range_table = rangeTable;
470 * if there is a result relation, initialize result relation stuff
472 if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
474 List *resultRelations = parseTree->resultRelations;
475 int numResultRelations;
476 ResultRelInfo *resultRelInfos;
478 if (resultRelations != NIL)
481 * Multiple result relations (due to inheritance)
482 * parseTree->resultRelations identifies them all
484 ResultRelInfo *resultRelInfo;
486 numResultRelations = length(resultRelations);
487 resultRelInfos = (ResultRelInfo *)
488 palloc(numResultRelations * sizeof(ResultRelInfo));
489 resultRelInfo = resultRelInfos;
490 while (resultRelations != NIL)
492 initResultRelInfo(resultRelInfo,
493 lfirsti(resultRelations),
497 resultRelations = lnext(resultRelations);
503 * Single result relation identified by
504 * parseTree->resultRelation
506 numResultRelations = 1;
507 resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
508 initResultRelInfo(resultRelInfos,
509 parseTree->resultRelation,
514 estate->es_result_relations = resultRelInfos;
515 estate->es_num_result_relations = numResultRelations;
516 /* Initialize to first or only result rel */
517 estate->es_result_relation_info = resultRelInfos;
522 * if no result relation, then set state appropriately
524 estate->es_result_relations = NULL;
525 estate->es_num_result_relations = 0;
526 estate->es_result_relation_info = NULL;
530 * Have to lock relations selected for update
532 estate->es_rowMark = NIL;
533 if (parseTree->rowMarks != NIL)
537 foreach(l, parseTree->rowMarks)
539 Index rti = lfirsti(l);
540 Oid relid = getrelid(rti, rangeTable);
544 relation = heap_open(relid, RowShareLock);
545 erm = (execRowMark *) palloc(sizeof(execRowMark));
546 erm->relation = relation;
548 snprintf(erm->resname, 32, "ctid%u", rti);
549 estate->es_rowMark = lappend(estate->es_rowMark, erm);
554 * initialize the executor "tuple" table. We need slots for all the
555 * plan nodes, plus possibly output slots for the junkfilter(s). At
556 * this point we aren't sure if we need junkfilters, so just add slots
557 * for them unconditionally.
560 int nSlots = ExecCountSlotsNode(plan);
562 if (parseTree->resultRelations != NIL)
563 nSlots += length(parseTree->resultRelations);
566 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
569 /* mark EvalPlanQual not active */
570 estate->es_origPlan = plan;
571 estate->es_evalPlanQual = NULL;
572 estate->es_evTuple = NULL;
573 estate->es_evTupleNull = NULL;
574 estate->es_useEvalPlan = false;
577 * initialize the private state information for all the nodes in the
578 * query tree. This opens files, allocates storage and leaves us
579 * ready to start processing tuples.
581 ExecInitNode(plan, estate, NULL);
584 * Get the tuple descriptor describing the type of tuples to return.
585 * (this is especially important if we are creating a relation with
588 tupType = ExecGetTupType(plan); /* tuple descriptor */
591 * Initialize the junk filter if needed. SELECT and INSERT queries
592 * need a filter if there are any junk attrs in the tlist. UPDATE and
593 * DELETE always need one, since there's always a junk 'ctid'
594 * attribute present --- no need to look first.
597 bool junk_filter_needed = false;
604 foreach(tlist, plan->targetlist)
606 TargetEntry *tle = (TargetEntry *) lfirst(tlist);
608 if (tle->resdom->resjunk)
610 junk_filter_needed = true;
617 junk_filter_needed = true;
623 if (junk_filter_needed)
626 * If there are multiple result relations, each one needs its
627 * own junk filter. Note this is only possible for
628 * UPDATE/DELETE, so we can't be fooled by some needing a
629 * filter and some not.
631 if (parseTree->resultRelations != NIL)
634 ResultRelInfo *resultRelInfo;
636 /* Top plan had better be an Append here. */
637 Assert(IsA(plan, Append));
638 Assert(((Append *) plan)->isTarget);
639 subplans = ((Append *) plan)->appendplans;
640 Assert(length(subplans) == estate->es_num_result_relations);
641 resultRelInfo = estate->es_result_relations;
642 while (subplans != NIL)
644 Plan *subplan = (Plan *) lfirst(subplans);
647 j = ExecInitJunkFilter(subplan->targetlist,
648 ExecGetTupType(subplan),
649 ExecAllocTableSlot(estate->es_tupleTable));
650 resultRelInfo->ri_junkFilter = j;
652 subplans = lnext(subplans);
656 * Set active junkfilter too; at this point ExecInitAppend
657 * has already selected an active result relation...
659 estate->es_junkFilter =
660 estate->es_result_relation_info->ri_junkFilter;
664 /* Normal case with just one JunkFilter */
667 j = ExecInitJunkFilter(plan->targetlist,
669 ExecAllocTableSlot(estate->es_tupleTable));
670 estate->es_junkFilter = j;
671 if (estate->es_result_relation_info)
672 estate->es_result_relation_info->ri_junkFilter = j;
674 /* For SELECT, want to return the cleaned tuple type */
675 if (operation == CMD_SELECT)
676 tupType = j->jf_cleanTupType;
680 estate->es_junkFilter = NULL;
684 * initialize the "into" relation
686 intoRelationDesc = (Relation) NULL;
688 if (operation == CMD_SELECT)
690 if (!parseTree->isPortal)
693 * a select into table --- need to create the "into" table
695 if (parseTree->into != NULL)
704 * find namespace to create in, check permissions
706 intoName = parseTree->into->relname;
707 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
709 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
711 if (aclresult != ACLCHECK_OK)
712 aclcheck_error(aclresult,
713 get_namespace_name(namespaceId));
716 * new "INTO" table is created WITH OIDS
718 tupType->tdhasoid = WITHOID;
720 * have to copy tupType to get rid of constraints
722 tupdesc = CreateTupleDescCopy(tupType);
725 heap_create_with_catalog(intoName,
731 allowSystemTableMods);
733 FreeTupleDesc(tupdesc);
736 * Advance command counter so that the newly-created
737 * relation's catalog tuples will be visible to heap_open.
739 CommandCounterIncrement();
742 * If necessary, create a TOAST table for the into
743 * relation. Note that AlterTableCreateToastTable ends
744 * with CommandCounterIncrement(), so that the TOAST table
745 * will be visible for insertion.
747 AlterTableCreateToastTable(intoRelationId, true);
749 intoRelationDesc = heap_open(intoRelationId,
750 AccessExclusiveLock);
755 estate->es_into_relation_descriptor = intoRelationDesc;
761 * Initialize ResultRelInfo data for one result relation
764 initResultRelInfo(ResultRelInfo *resultRelInfo,
765 Index resultRelationIndex,
769 Oid resultRelationOid;
770 Relation resultRelationDesc;
772 resultRelationOid = getrelid(resultRelationIndex, rangeTable);
773 resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
775 switch (resultRelationDesc->rd_rel->relkind)
777 case RELKIND_SEQUENCE:
778 elog(ERROR, "You can't change sequence relation %s",
779 RelationGetRelationName(resultRelationDesc));
781 case RELKIND_TOASTVALUE:
782 elog(ERROR, "You can't change toast relation %s",
783 RelationGetRelationName(resultRelationDesc));
786 elog(ERROR, "You can't change view relation %s",
787 RelationGetRelationName(resultRelationDesc));
791 MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
792 resultRelInfo->type = T_ResultRelInfo;
793 resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
794 resultRelInfo->ri_RelationDesc = resultRelationDesc;
795 resultRelInfo->ri_NumIndices = 0;
796 resultRelInfo->ri_IndexRelationDescs = NULL;
797 resultRelInfo->ri_IndexRelationInfo = NULL;
798 resultRelInfo->ri_TrigDesc = resultRelationDesc->trigdesc;
799 resultRelInfo->ri_TrigFunctions = NULL;
800 resultRelInfo->ri_ConstraintExprs = NULL;
801 resultRelInfo->ri_junkFilter = NULL;
804 * If there are indices on the result relation, open them and save
805 * descriptors in the result relation info, so that we can add new
806 * index entries for the tuples we add/update. We need not do this
807 * for a DELETE, however, since deletion doesn't affect indexes.
809 if (resultRelationDesc->rd_rel->relhasindex &&
810 operation != CMD_DELETE)
811 ExecOpenIndices(resultRelInfo);
814 /* ----------------------------------------------------------------
817 * Cleans up the query plan -- closes files and free up storages
818 * ----------------------------------------------------------------
821 EndPlan(Plan *plan, EState *estate)
823 ResultRelInfo *resultRelInfo;
828 * shut down any PlanQual processing we were doing
830 if (estate->es_evalPlanQual != NULL)
831 EndEvalPlanQual(estate);
834 * shut down the node-type-specific query processing
836 ExecEndNode(plan, NULL);
839 * destroy the executor "tuple" table.
841 ExecDropTupleTable(estate->es_tupleTable, true);
842 estate->es_tupleTable = NULL;
845 * close the result relation(s) if any, but hold locks until xact
846 * commit. Also clean up junkfilters if present.
848 resultRelInfo = estate->es_result_relations;
849 for (i = estate->es_num_result_relations; i > 0; i--)
851 /* Close indices and then the relation itself */
852 ExecCloseIndices(resultRelInfo);
853 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
854 /* Delete the junkfilter if any */
855 if (resultRelInfo->ri_junkFilter != NULL)
856 ExecFreeJunkFilter(resultRelInfo->ri_junkFilter);
861 * close the "into" relation if necessary, again keeping lock
863 if (estate->es_into_relation_descriptor != NULL)
864 heap_close(estate->es_into_relation_descriptor, NoLock);
867 * There might be a junkfilter without a result relation.
869 if (estate->es_num_result_relations == 0 &&
870 estate->es_junkFilter != NULL)
872 ExecFreeJunkFilter(estate->es_junkFilter);
873 estate->es_junkFilter = NULL;
877 * close any relations selected FOR UPDATE, again keeping locks
879 foreach(l, estate->es_rowMark)
881 execRowMark *erm = lfirst(l);
883 heap_close(erm->relation, NoLock);
887 /* ----------------------------------------------------------------
890 * processes the query plan to retrieve 'numberTuples' tuples in the
891 * direction specified.
892 * Retrieves all tuples if numberTuples is 0
894 * result is either a slot containing the last tuple in the case
895 * of a SELECT or NULL otherwise.
897 * Note: the ctid attribute is a 'junk' attribute that is removed before the
899 * ----------------------------------------------------------------
901 static TupleTableSlot *
902 ExecutePlan(EState *estate,
906 ScanDirection direction,
907 DestReceiver *destfunc)
909 JunkFilter *junkfilter;
910 TupleTableSlot *slot;
911 ItemPointer tupleid = NULL;
912 ItemPointerData tuple_ctid;
913 long current_tuple_count;
914 TupleTableSlot *result;
917 * initialize local variables
920 current_tuple_count = 0;
926 estate->es_direction = direction;
929 * Loop until we've processed the proper number of tuples from the
935 /* Reset the per-output-tuple exprcontext */
936 ResetPerTupleExprContext(estate);
939 * Execute the plan and obtain a tuple
942 if (estate->es_useEvalPlan)
944 slot = EvalPlanQualNext(estate);
946 slot = ExecProcNode(plan, NULL);
949 slot = ExecProcNode(plan, NULL);
952 * if the tuple is null, then we assume there is nothing more to
953 * process so we just return null...
962 * if we have a junk filter, then project a new tuple with the
965 * Store this new "clean" tuple in the junkfilter's resultSlot.
966 * (Formerly, we stored it back over the "dirty" tuple, which is
967 * WRONG because that tuple slot has the wrong descriptor.)
969 * Also, extract all the junk information we need.
971 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
978 * extract the 'ctid' junk attribute.
980 if (operation == CMD_UPDATE || operation == CMD_DELETE)
982 if (!ExecGetJunkAttribute(junkfilter,
987 elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
989 /* shouldn't ever get a null result... */
991 elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
993 tupleid = (ItemPointer) DatumGetPointer(datum);
994 tuple_ctid = *tupleid; /* make sure we don't free the
996 tupleid = &tuple_ctid;
998 else if (estate->es_rowMark != NIL)
1003 foreach(l, estate->es_rowMark)
1005 execRowMark *erm = lfirst(l);
1007 HeapTupleData tuple;
1008 TupleTableSlot *newSlot;
1011 if (!ExecGetJunkAttribute(junkfilter,
1016 elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
1019 /* shouldn't ever get a null result... */
1021 elog(ERROR, "ExecutePlan: (junk) `%s' is NULL!",
1024 tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1025 test = heap_mark4update(erm->relation, &tuple, &buffer,
1026 estate->es_snapshot->curcid);
1027 ReleaseBuffer(buffer);
1030 case HeapTupleSelfUpdated:
1031 case HeapTupleMayBeUpdated:
1034 case HeapTupleUpdated:
1035 if (XactIsoLevel == XACT_SERIALIZABLE)
1036 elog(ERROR, "Can't serialize access due to concurrent update");
1037 if (!(ItemPointerEquals(&(tuple.t_self),
1038 (ItemPointer) DatumGetPointer(datum))))
1040 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1041 if (!(TupIsNull(newSlot)))
1044 estate->es_useEvalPlan = true;
1050 * if tuple was deleted or PlanQual failed for
1051 * updated tuple - we must not return this
1057 elog(ERROR, "Unknown status %u from heap_mark4update", test);
1064 * Finally create a new "clean" tuple with all junk attributes
1067 newTuple = ExecRemoveJunk(junkfilter, slot);
1069 slot = ExecStoreTuple(newTuple, /* tuple to store */
1070 junkfilter->jf_resultSlot, /* dest slot */
1071 InvalidBuffer, /* this tuple has no buffer */
1072 true); /* tuple should be pfreed */
1076 * now that we have a tuple, do the appropriate thing with it..
1077 * either return it to the user, add it to a relation someplace,
1078 * delete it from a relation, or modify some of its attributes.
1083 ExecSelect(slot, /* slot containing tuple */
1084 destfunc, /* destination's tuple-receiver obj */
1090 ExecInsert(slot, tupleid, estate);
1095 ExecDelete(slot, tupleid, estate);
1100 ExecUpdate(slot, tupleid, estate);
1105 elog(LOG, "ExecutePlan: unknown operation in queryDesc");
1111 * check our tuple count.. if we've processed the proper number
1112 * then quit, else loop again and process more tuples..
1114 current_tuple_count++;
1115 if (numberTuples == current_tuple_count)
1120 * here, result is either a slot containing a tuple in the case of a
1121 * SELECT or NULL otherwise.
1126 /* ----------------------------------------------------------------
1129 * SELECTs are easy.. we just pass the tuple to the appropriate
1130 * print function. The only complexity is when we do a
1131 * "SELECT INTO", in which case we insert the tuple into
1132 * the appropriate relation (note: this is a newly created relation
1133 * so we don't need to worry about indices or locks.)
1134 * ----------------------------------------------------------------
1137 ExecSelect(TupleTableSlot *slot,
1138 DestReceiver *destfunc,
1145 * get the heap tuple out of the tuple table slot
1148 attrtype = slot->ttc_tupleDescriptor;
1151 * insert the tuple into the "into relation"
1153 if (estate->es_into_relation_descriptor != NULL)
1155 heap_insert(estate->es_into_relation_descriptor, tuple,
1156 estate->es_snapshot->curcid);
1161 * send the tuple to the front end (or the screen)
1163 (*destfunc->receiveTuple) (tuple, attrtype, destfunc);
1165 (estate->es_processed)++;
1168 /* ----------------------------------------------------------------
1171 * INSERTs are trickier.. we have to insert the tuple into
1172 * the base relation and insert appropriate tuples into the
1174 * ----------------------------------------------------------------
1177 ExecInsert(TupleTableSlot *slot,
1178 ItemPointer tupleid,
1182 ResultRelInfo *resultRelInfo;
1183 Relation resultRelationDesc;
1188 * get the heap tuple out of the tuple table slot
1193 * get information on the (current) result relation
1195 resultRelInfo = estate->es_result_relation_info;
1196 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1198 /* BEFORE ROW INSERT Triggers */
1199 if (resultRelInfo->ri_TrigDesc &&
1200 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1204 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1206 if (newtuple == NULL) /* "do nothing" */
1209 if (newtuple != tuple) /* modified by Trigger(s) */
1212 * Insert modified tuple into tuple table slot, replacing the
1213 * original. We assume that it was allocated in per-tuple
1214 * memory context, and therefore will go away by itself. The
1215 * tuple table slot should not try to clear it.
1217 ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1223 * Check the constraints of the tuple
1225 if (resultRelationDesc->rd_att->constr)
1226 ExecConstraints("ExecInsert", resultRelInfo, slot, estate);
1231 newId = heap_insert(resultRelationDesc, tuple,
1232 estate->es_snapshot->curcid);
1235 (estate->es_processed)++;
1236 estate->es_lastoid = newId;
1237 setLastTid(&(tuple->t_self));
1242 * Note: heap_insert adds a new tuple to a relation. As a side effect,
1243 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1246 numIndices = resultRelInfo->ri_NumIndices;
1248 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1250 /* AFTER ROW INSERT Triggers */
1251 if (resultRelInfo->ri_TrigDesc)
1252 ExecARInsertTriggers(estate, resultRelInfo, tuple);
1255 /* ----------------------------------------------------------------
1258 * DELETE is like UPDATE, we delete the tuple and its
1260 * ----------------------------------------------------------------
1263 ExecDelete(TupleTableSlot *slot,
1264 ItemPointer tupleid,
1267 ResultRelInfo *resultRelInfo;
1268 Relation resultRelationDesc;
1269 ItemPointerData ctid;
1273 * get information on the (current) result relation
1275 resultRelInfo = estate->es_result_relation_info;
1276 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1278 /* BEFORE ROW DELETE Triggers */
1279 if (resultRelInfo->ri_TrigDesc &&
1280 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1284 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid);
1286 if (!dodelete) /* "do nothing" */
1294 result = heap_delete(resultRelationDesc, tupleid,
1296 estate->es_snapshot->curcid);
1299 case HeapTupleSelfUpdated:
1302 case HeapTupleMayBeUpdated:
1305 case HeapTupleUpdated:
1306 if (XactIsoLevel == XACT_SERIALIZABLE)
1307 elog(ERROR, "Can't serialize access due to concurrent update");
1308 else if (!(ItemPointerEquals(tupleid, &ctid)))
1310 TupleTableSlot *epqslot = EvalPlanQual(estate,
1311 resultRelInfo->ri_RangeTableIndex, &ctid);
1313 if (!TupIsNull(epqslot))
1319 /* tuple already deleted; nothing to do */
1323 elog(ERROR, "Unknown status %u from heap_delete", result);
1328 (estate->es_processed)++;
1331 * Note: Normally one would think that we have to delete index tuples
1332 * associated with the heap tuple now..
1334 * ... but in POSTGRES, we have no need to do this because the vacuum
1335 * daemon automatically opens an index scan and deletes index tuples
1336 * when it finds deleted heap tuples. -cim 9/27/89
1339 /* AFTER ROW DELETE Triggers */
1340 if (resultRelInfo->ri_TrigDesc)
1341 ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1344 /* ----------------------------------------------------------------
1347 * note: we can't run UPDATE queries with transactions
1348 * off because UPDATEs are actually INSERTs and our
1349 * scan will mistakenly loop forever, updating the tuple
1350 * it just inserted.. This should be fixed but until it
1351 * is, we don't want to get stuck in an infinite loop
1352 * which corrupts your database..
1353 * ----------------------------------------------------------------
1356 ExecUpdate(TupleTableSlot *slot,
1357 ItemPointer tupleid,
1361 ResultRelInfo *resultRelInfo;
1362 Relation resultRelationDesc;
1363 ItemPointerData ctid;
1368 * abort the operation if not running transactions
1370 if (IsBootstrapProcessingMode())
1372 elog(WARNING, "ExecUpdate: UPDATE can't run without transactions");
1377 * get the heap tuple out of the tuple table slot
1382 * get information on the (current) result relation
1384 resultRelInfo = estate->es_result_relation_info;
1385 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1387 /* BEFORE ROW UPDATE Triggers */
1388 if (resultRelInfo->ri_TrigDesc &&
1389 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1393 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1396 if (newtuple == NULL) /* "do nothing" */
1399 if (newtuple != tuple) /* modified by Trigger(s) */
1402 * Insert modified tuple into tuple table slot, replacing the
1403 * original. We assume that it was allocated in per-tuple
1404 * memory context, and therefore will go away by itself. The
1405 * tuple table slot should not try to clear it.
1407 ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1413 * Check the constraints of the tuple
1415 * If we generate a new candidate tuple after EvalPlanQual testing, we
1416 * must loop back here and recheck constraints. (We don't need to
1417 * redo triggers, however. If there are any BEFORE triggers then
1418 * trigger.c will have done mark4update to lock the correct tuple, so
1419 * there's no need to do them again.)
1422 if (resultRelationDesc->rd_att->constr)
1423 ExecConstraints("ExecUpdate", resultRelInfo, slot, estate);
1426 * replace the heap tuple
1428 result = heap_update(resultRelationDesc, tupleid, tuple,
1430 estate->es_snapshot->curcid);
1433 case HeapTupleSelfUpdated:
1436 case HeapTupleMayBeUpdated:
1439 case HeapTupleUpdated:
1440 if (XactIsoLevel == XACT_SERIALIZABLE)
1441 elog(ERROR, "Can't serialize access due to concurrent update");
1442 else if (!(ItemPointerEquals(tupleid, &ctid)))
1444 TupleTableSlot *epqslot = EvalPlanQual(estate,
1445 resultRelInfo->ri_RangeTableIndex, &ctid);
1447 if (!TupIsNull(epqslot))
1450 tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1451 slot = ExecStoreTuple(tuple,
1452 estate->es_junkFilter->jf_resultSlot,
1453 InvalidBuffer, true);
1457 /* tuple already deleted; nothing to do */
1461 elog(ERROR, "Unknown status %u from heap_update", result);
1466 (estate->es_processed)++;
1469 * Note: instead of having to update the old index tuples associated
1470 * with the heap tuple, all we do is form and insert new index tuples.
1471 * This is because UPDATEs are actually DELETEs and INSERTs and index
1472 * tuple deletion is done automagically by the vacuum daemon. All we
1473 * do is insert new index tuples. -cim 9/27/89
1479 * heap_update updates a tuple in the base relation by invalidating it
1480 * and then inserting a new tuple to the relation. As a side effect,
1481 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1482 * field. So we now insert index tuples using the new tupleid stored
1486 numIndices = resultRelInfo->ri_NumIndices;
1488 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1490 /* AFTER ROW UPDATE Triggers */
1491 if (resultRelInfo->ri_TrigDesc)
1492 ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1496 ExecRelCheck(ResultRelInfo *resultRelInfo,
1497 TupleTableSlot *slot, EState *estate)
1499 Relation rel = resultRelInfo->ri_RelationDesc;
1500 int ncheck = rel->rd_att->constr->num_check;
1501 ConstrCheck *check = rel->rd_att->constr->check;
1502 ExprContext *econtext;
1503 MemoryContext oldContext;
1508 * If first time through for this result relation, build expression
1509 * nodetrees for rel's constraint expressions. Keep them in the
1510 * per-query memory context so they'll survive throughout the query.
1512 if (resultRelInfo->ri_ConstraintExprs == NULL)
1514 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1515 resultRelInfo->ri_ConstraintExprs =
1516 (List **) palloc(ncheck * sizeof(List *));
1517 for (i = 0; i < ncheck; i++)
1519 qual = (List *) stringToNode(check[i].ccbin);
1520 resultRelInfo->ri_ConstraintExprs[i] = qual;
1522 MemoryContextSwitchTo(oldContext);
1526 * We will use the EState's per-tuple context for evaluating
1527 * constraint expressions (creating it if it's not already there).
1529 econtext = GetPerTupleExprContext(estate);
1531 /* Arrange for econtext's scan tuple to be the tuple under test */
1532 econtext->ecxt_scantuple = slot;
1534 /* And evaluate the constraints */
1535 for (i = 0; i < ncheck; i++)
1537 qual = resultRelInfo->ri_ConstraintExprs[i];
1540 * NOTE: SQL92 specifies that a NULL result from a constraint
1541 * expression is not to be treated as a failure. Therefore, tell
1542 * ExecQual to return TRUE for NULL.
1544 if (!ExecQual(qual, econtext, true))
1545 return check[i].ccname;
1548 /* NULL result means no error */
1549 return (char *) NULL;
1553 ExecConstraints(const char *caller, ResultRelInfo *resultRelInfo,
1554 TupleTableSlot *slot, EState *estate)
1556 Relation rel = resultRelInfo->ri_RelationDesc;
1557 HeapTuple tuple = slot->val;
1558 TupleConstr *constr = rel->rd_att->constr;
1562 if (constr->has_not_null)
1564 int natts = rel->rd_att->natts;
1567 for (attrChk = 1; attrChk <= natts; attrChk++)
1569 if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1570 heap_attisnull(tuple, attrChk))
1571 elog(ERROR, "%s: Fail to add null value in not null attribute %s",
1572 caller, NameStr(rel->rd_att->attrs[attrChk - 1]->attname));
1576 if (constr->num_check > 0)
1580 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1581 elog(ERROR, "%s: rejected due to CHECK constraint \"%s\" on \"%s\"",
1582 caller, failed, RelationGetRelationName(rel));
1587 * Check a modified tuple to see if we want to process its updated version
1588 * under READ COMMITTED rules.
1590 * See backend/executor/README for some info about how this works.
1593 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1598 HeapTupleData tuple;
1599 HeapTuple copyTuple = NULL;
1606 * find relation containing target tuple
1608 if (estate->es_result_relation_info != NULL &&
1609 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1610 relation = estate->es_result_relation_info->ri_RelationDesc;
1616 foreach(l, estate->es_rowMark)
1618 if (((execRowMark *) lfirst(l))->rti == rti)
1620 relation = ((execRowMark *) lfirst(l))->relation;
1624 if (relation == NULL)
1625 elog(ERROR, "EvalPlanQual: can't find RTE %d", (int) rti);
1631 * Loop here to deal with updated or busy tuples
1633 tuple.t_self = *tid;
1638 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1640 TransactionId xwait = SnapshotDirty->xmax;
1642 if (TransactionIdIsValid(SnapshotDirty->xmin))
1643 elog(ERROR, "EvalPlanQual: t_xmin is uncommitted ?!");
1646 * If tuple is being updated by other transaction then we have
1647 * to wait for its commit/abort.
1649 if (TransactionIdIsValid(xwait))
1651 ReleaseBuffer(buffer);
1652 XactLockTableWait(xwait);
1657 * We got tuple - now copy it for use by recheck query.
1659 copyTuple = heap_copytuple(&tuple);
1660 ReleaseBuffer(buffer);
1665 * Oops! Invalid tuple. Have to check is it updated or deleted.
1666 * Note that it's possible to get invalid SnapshotDirty->tid if
1667 * tuple updated by this transaction. Have we to check this ?
1669 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1670 !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1672 /* updated, so look at the updated copy */
1673 tuple.t_self = SnapshotDirty->tid;
1678 * Deleted or updated by this transaction; forget it.
1684 * For UPDATE/DELETE we have to return tid of actual row we're
1687 *tid = tuple.t_self;
1690 * Need to run a recheck subquery. Find or create a PQ stack entry.
1692 epq = (evalPlanQual *) estate->es_evalPlanQual;
1693 rtsize = length(estate->es_range_table);
1696 if (epq != NULL && epq->rti == 0)
1698 /* Top PQ stack entry is idle, so re-use it */
1699 Assert(!(estate->es_useEvalPlan) &&
1700 epq->estate.es_evalPlanQual == NULL);
1706 * If this is request for another RTE - Ra, - then we have to check
1707 * wasn't PlanQual requested for Ra already and if so then Ra' row was
1708 * updated again and we have to re-start old execution for Ra and
1709 * forget all what we done after Ra was suspended. Cool? -:))
1711 if (epq != NULL && epq->rti != rti &&
1712 epq->estate.es_evTuple[rti - 1] != NULL)
1716 evalPlanQual *oldepq;
1718 /* pop previous PlanQual from the stack */
1719 epqstate = &(epq->estate);
1720 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1721 Assert(oldepq->rti != 0);
1722 /* stop execution */
1723 ExecEndNode(epq->plan, NULL);
1724 ExecDropTupleTable(epqstate->es_tupleTable, true);
1725 epqstate->es_tupleTable = NULL;
1726 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1727 epqstate->es_evTuple[epq->rti - 1] = NULL;
1728 /* push current PQ to freePQ stack */
1731 estate->es_evalPlanQual = (Pointer) epq;
1732 } while (epq->rti != rti);
1736 * If we are requested for another RTE then we have to suspend
1737 * execution of current PlanQual and start execution for new one.
1739 if (epq == NULL || epq->rti != rti)
1741 /* try to reuse plan used previously */
1742 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1744 if (newepq == NULL) /* first call or freePQ stack is empty */
1746 newepq = (evalPlanQual *) palloc(sizeof(evalPlanQual));
1747 newepq->free = NULL;
1750 * Each stack level has its own copy of the plan tree. This
1751 * is wasteful, but necessary as long as plan nodes point to
1752 * exec state nodes rather than vice versa. Note that
1753 * copyfuncs.c doesn't attempt to copy the exec state nodes,
1754 * which is a good thing in this situation.
1756 newepq->plan = copyObject(estate->es_origPlan);
1759 * Init stack level's EState. We share top level's copy of
1760 * es_result_relations array and other non-changing status. We
1761 * need our own tupletable, es_param_exec_vals, and other
1764 epqstate = &(newepq->estate);
1765 memcpy(epqstate, estate, sizeof(EState));
1766 epqstate->es_direction = ForwardScanDirection;
1767 if (estate->es_origPlan->nParamExec > 0)
1768 epqstate->es_param_exec_vals = (ParamExecData *)
1769 palloc(estate->es_origPlan->nParamExec *
1770 sizeof(ParamExecData));
1771 epqstate->es_tupleTable = NULL;
1772 epqstate->es_per_tuple_exprcontext = NULL;
1775 * Each epqstate must have its own es_evTupleNull state, but
1776 * all the stack entries share es_evTuple state. This allows
1777 * sub-rechecks to inherit the value being examined by an
1780 epqstate->es_evTupleNull = (bool *) palloc(rtsize * sizeof(bool));
1783 /* first PQ stack entry */
1784 epqstate->es_evTuple = (HeapTuple *)
1785 palloc(rtsize * sizeof(HeapTuple));
1786 memset(epqstate->es_evTuple, 0, rtsize * sizeof(HeapTuple));
1790 /* later stack entries share the same storage */
1791 epqstate->es_evTuple = epq->estate.es_evTuple;
1796 /* recycle previously used EState */
1797 epqstate = &(newepq->estate);
1799 /* push current PQ to the stack */
1800 epqstate->es_evalPlanQual = (Pointer) epq;
1802 estate->es_evalPlanQual = (Pointer) epq;
1807 Assert(epq->rti == rti);
1808 epqstate = &(epq->estate);
1811 * Ok - we're requested for the same RTE. Unfortunately we still have
1812 * to end and restart execution of the plan, because ExecReScan
1813 * wouldn't ensure that upper plan nodes would reset themselves. We
1814 * could make that work if insertion of the target tuple were
1815 * integrated with the Param mechanism somehow, so that the upper plan
1816 * nodes know that their children's outputs have changed.
1820 /* stop execution */
1821 ExecEndNode(epq->plan, NULL);
1822 ExecDropTupleTable(epqstate->es_tupleTable, true);
1823 epqstate->es_tupleTable = NULL;
1827 * free old RTE' tuple, if any, and store target tuple where
1828 * relation's scan node will see it
1830 if (epqstate->es_evTuple[rti - 1] != NULL)
1831 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1832 epqstate->es_evTuple[rti - 1] = copyTuple;
1835 * Initialize for new recheck query; be careful to copy down state
1836 * that might have changed in top EState.
1838 epqstate->es_result_relation_info = estate->es_result_relation_info;
1839 epqstate->es_junkFilter = estate->es_junkFilter;
1840 if (estate->es_origPlan->nParamExec > 0)
1841 memset(epqstate->es_param_exec_vals, 0,
1842 estate->es_origPlan->nParamExec * sizeof(ParamExecData));
1843 memset(epqstate->es_evTupleNull, false, rtsize * sizeof(bool));
1844 epqstate->es_useEvalPlan = false;
1845 Assert(epqstate->es_tupleTable == NULL);
1846 epqstate->es_tupleTable =
1847 ExecCreateTupleTable(estate->es_tupleTable->size);
1849 ExecInitNode(epq->plan, epqstate, NULL);
1851 return EvalPlanQualNext(estate);
1854 static TupleTableSlot *
1855 EvalPlanQualNext(EState *estate)
1857 evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1858 EState *epqstate = &(epq->estate);
1859 evalPlanQual *oldepq;
1860 TupleTableSlot *slot;
1862 Assert(epq->rti != 0);
1865 slot = ExecProcNode(epq->plan, NULL);
1868 * No more tuples for this PQ. Continue previous one.
1870 if (TupIsNull(slot))
1872 /* stop execution */
1873 ExecEndNode(epq->plan, NULL);
1874 ExecDropTupleTable(epqstate->es_tupleTable, true);
1875 epqstate->es_tupleTable = NULL;
1876 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1877 epqstate->es_evTuple[epq->rti - 1] = NULL;
1878 /* pop old PQ from the stack */
1879 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1880 if (oldepq == (evalPlanQual *) NULL)
1882 epq->rti = 0; /* this is the first (oldest) */
1883 estate->es_useEvalPlan = false; /* PQ - mark as free and */
1884 return (NULL); /* continue Query execution */
1886 Assert(oldepq->rti != 0);
1887 /* push current PQ to freePQ stack */
1890 epqstate = &(epq->estate);
1891 estate->es_evalPlanQual = (Pointer) epq;
1899 EndEvalPlanQual(EState *estate)
1901 evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1902 EState *epqstate = &(epq->estate);
1903 evalPlanQual *oldepq;
1905 if (epq->rti == 0) /* plans already shutdowned */
1907 Assert(epq->estate.es_evalPlanQual == NULL);
1913 /* stop execution */
1914 ExecEndNode(epq->plan, NULL);
1915 ExecDropTupleTable(epqstate->es_tupleTable, true);
1916 epqstate->es_tupleTable = NULL;
1917 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1919 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1920 epqstate->es_evTuple[epq->rti - 1] = NULL;
1922 /* pop old PQ from the stack */
1923 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1924 if (oldepq == (evalPlanQual *) NULL)
1926 epq->rti = 0; /* this is the first (oldest) */
1927 estate->es_useEvalPlan = false; /* PQ - mark as free */
1930 Assert(oldepq->rti != 0);
1931 /* push current PQ to freePQ stack */
1934 epqstate = &(epq->estate);
1935 estate->es_evalPlanQual = (Pointer) epq;