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11 * The old ExecutorMain() has been replaced by ExecutorStart(),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 1.171 2002/07/20 05:16:57 momjian 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 sprintf(erm->resname, "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)
703 * find namespace to create in, check permissions
705 intoName = parseTree->into->relname;
706 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
708 if (!isTempNamespace(namespaceId))
712 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
714 if (aclresult != ACLCHECK_OK)
715 aclcheck_error(aclresult,
716 get_namespace_name(namespaceId));
720 * new "INTO" table is created WITH OIDS
722 tupType->tdhasoid = WITHOID;
724 * have to copy tupType to get rid of constraints
726 tupdesc = CreateTupleDescCopy(tupType);
729 heap_create_with_catalog(intoName,
735 allowSystemTableMods);
737 FreeTupleDesc(tupdesc);
740 * Advance command counter so that the newly-created
741 * relation's catalog tuples will be visible to heap_open.
743 CommandCounterIncrement();
746 * If necessary, create a TOAST table for the into
747 * relation. Note that AlterTableCreateToastTable ends
748 * with CommandCounterIncrement(), so that the TOAST table
749 * will be visible for insertion.
751 AlterTableCreateToastTable(intoRelationId, true);
753 intoRelationDesc = heap_open(intoRelationId,
754 AccessExclusiveLock);
759 estate->es_into_relation_descriptor = intoRelationDesc;
765 * Initialize ResultRelInfo data for one result relation
768 initResultRelInfo(ResultRelInfo *resultRelInfo,
769 Index resultRelationIndex,
773 Oid resultRelationOid;
774 Relation resultRelationDesc;
776 resultRelationOid = getrelid(resultRelationIndex, rangeTable);
777 resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
779 switch (resultRelationDesc->rd_rel->relkind)
781 case RELKIND_SEQUENCE:
782 elog(ERROR, "You can't change sequence relation %s",
783 RelationGetRelationName(resultRelationDesc));
785 case RELKIND_TOASTVALUE:
786 elog(ERROR, "You can't change toast relation %s",
787 RelationGetRelationName(resultRelationDesc));
790 elog(ERROR, "You can't change view relation %s",
791 RelationGetRelationName(resultRelationDesc));
795 MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
796 resultRelInfo->type = T_ResultRelInfo;
797 resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
798 resultRelInfo->ri_RelationDesc = resultRelationDesc;
799 resultRelInfo->ri_NumIndices = 0;
800 resultRelInfo->ri_IndexRelationDescs = NULL;
801 resultRelInfo->ri_IndexRelationInfo = NULL;
802 resultRelInfo->ri_TrigDesc = resultRelationDesc->trigdesc;
803 resultRelInfo->ri_TrigFunctions = NULL;
804 resultRelInfo->ri_ConstraintExprs = NULL;
805 resultRelInfo->ri_junkFilter = NULL;
808 * If there are indices on the result relation, open them and save
809 * descriptors in the result relation info, so that we can add new
810 * index entries for the tuples we add/update. We need not do this
811 * for a DELETE, however, since deletion doesn't affect indexes.
813 if (resultRelationDesc->rd_rel->relhasindex &&
814 operation != CMD_DELETE)
815 ExecOpenIndices(resultRelInfo);
818 /* ----------------------------------------------------------------
821 * Cleans up the query plan -- closes files and free up storages
822 * ----------------------------------------------------------------
825 EndPlan(Plan *plan, EState *estate)
827 ResultRelInfo *resultRelInfo;
832 * shut down any PlanQual processing we were doing
834 if (estate->es_evalPlanQual != NULL)
835 EndEvalPlanQual(estate);
838 * shut down the node-type-specific query processing
840 ExecEndNode(plan, NULL);
843 * destroy the executor "tuple" table.
845 ExecDropTupleTable(estate->es_tupleTable, true);
846 estate->es_tupleTable = NULL;
849 * close the result relation(s) if any, but hold locks until xact
850 * commit. Also clean up junkfilters if present.
852 resultRelInfo = estate->es_result_relations;
853 for (i = estate->es_num_result_relations; i > 0; i--)
855 /* Close indices and then the relation itself */
856 ExecCloseIndices(resultRelInfo);
857 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
858 /* Delete the junkfilter if any */
859 if (resultRelInfo->ri_junkFilter != NULL)
860 ExecFreeJunkFilter(resultRelInfo->ri_junkFilter);
865 * close the "into" relation if necessary, again keeping lock
867 if (estate->es_into_relation_descriptor != NULL)
868 heap_close(estate->es_into_relation_descriptor, NoLock);
871 * There might be a junkfilter without a result relation.
873 if (estate->es_num_result_relations == 0 &&
874 estate->es_junkFilter != NULL)
876 ExecFreeJunkFilter(estate->es_junkFilter);
877 estate->es_junkFilter = NULL;
881 * close any relations selected FOR UPDATE, again keeping locks
883 foreach(l, estate->es_rowMark)
885 execRowMark *erm = lfirst(l);
887 heap_close(erm->relation, NoLock);
891 /* ----------------------------------------------------------------
894 * processes the query plan to retrieve 'numberTuples' tuples in the
895 * direction specified.
896 * Retrieves all tuples if numberTuples is 0
898 * result is either a slot containing the last tuple in the case
899 * of a SELECT or NULL otherwise.
901 * Note: the ctid attribute is a 'junk' attribute that is removed before the
903 * ----------------------------------------------------------------
905 static TupleTableSlot *
906 ExecutePlan(EState *estate,
910 ScanDirection direction,
911 DestReceiver *destfunc)
913 JunkFilter *junkfilter;
914 TupleTableSlot *slot;
915 ItemPointer tupleid = NULL;
916 ItemPointerData tuple_ctid;
917 long current_tuple_count;
918 TupleTableSlot *result;
921 * initialize local variables
924 current_tuple_count = 0;
930 estate->es_direction = direction;
933 * Loop until we've processed the proper number of tuples from the
939 /* Reset the per-output-tuple exprcontext */
940 ResetPerTupleExprContext(estate);
943 * Execute the plan and obtain a tuple
946 if (estate->es_useEvalPlan)
948 slot = EvalPlanQualNext(estate);
950 slot = ExecProcNode(plan, NULL);
953 slot = ExecProcNode(plan, NULL);
956 * if the tuple is null, then we assume there is nothing more to
957 * process so we just return null...
966 * if we have a junk filter, then project a new tuple with the
969 * Store this new "clean" tuple in the junkfilter's resultSlot.
970 * (Formerly, we stored it back over the "dirty" tuple, which is
971 * WRONG because that tuple slot has the wrong descriptor.)
973 * Also, extract all the junk information we need.
975 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
982 * extract the 'ctid' junk attribute.
984 if (operation == CMD_UPDATE || operation == CMD_DELETE)
986 if (!ExecGetJunkAttribute(junkfilter,
991 elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
993 /* shouldn't ever get a null result... */
995 elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
997 tupleid = (ItemPointer) DatumGetPointer(datum);
998 tuple_ctid = *tupleid; /* make sure we don't free the
1000 tupleid = &tuple_ctid;
1002 else if (estate->es_rowMark != NIL)
1007 foreach(l, estate->es_rowMark)
1009 execRowMark *erm = lfirst(l);
1011 HeapTupleData tuple;
1012 TupleTableSlot *newSlot;
1015 if (!ExecGetJunkAttribute(junkfilter,
1020 elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
1023 /* shouldn't ever get a null result... */
1025 elog(ERROR, "ExecutePlan: (junk) `%s' is NULL!",
1028 tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1029 test = heap_mark4update(erm->relation, &tuple, &buffer,
1030 estate->es_snapshot->curcid);
1031 ReleaseBuffer(buffer);
1034 case HeapTupleSelfUpdated:
1035 case HeapTupleMayBeUpdated:
1038 case HeapTupleUpdated:
1039 if (XactIsoLevel == XACT_SERIALIZABLE)
1040 elog(ERROR, "Can't serialize access due to concurrent update");
1041 if (!(ItemPointerEquals(&(tuple.t_self),
1042 (ItemPointer) DatumGetPointer(datum))))
1044 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1045 if (!(TupIsNull(newSlot)))
1048 estate->es_useEvalPlan = true;
1054 * if tuple was deleted or PlanQual failed for
1055 * updated tuple - we must not return this
1061 elog(ERROR, "Unknown status %u from heap_mark4update", test);
1068 * Finally create a new "clean" tuple with all junk attributes
1071 newTuple = ExecRemoveJunk(junkfilter, slot);
1073 slot = ExecStoreTuple(newTuple, /* tuple to store */
1074 junkfilter->jf_resultSlot, /* dest slot */
1075 InvalidBuffer, /* this tuple has no buffer */
1076 true); /* tuple should be pfreed */
1080 * now that we have a tuple, do the appropriate thing with it..
1081 * either return it to the user, add it to a relation someplace,
1082 * delete it from a relation, or modify some of its attributes.
1087 ExecSelect(slot, /* slot containing tuple */
1088 destfunc, /* destination's tuple-receiver obj */
1094 ExecInsert(slot, tupleid, estate);
1099 ExecDelete(slot, tupleid, estate);
1104 ExecUpdate(slot, tupleid, estate);
1109 elog(LOG, "ExecutePlan: unknown operation in queryDesc");
1115 * check our tuple count.. if we've processed the proper number
1116 * then quit, else loop again and process more tuples..
1118 current_tuple_count++;
1119 if (numberTuples == current_tuple_count)
1124 * here, result is either a slot containing a tuple in the case of a
1125 * SELECT or NULL otherwise.
1130 /* ----------------------------------------------------------------
1133 * SELECTs are easy.. we just pass the tuple to the appropriate
1134 * print function. The only complexity is when we do a
1135 * "SELECT INTO", in which case we insert the tuple into
1136 * the appropriate relation (note: this is a newly created relation
1137 * so we don't need to worry about indices or locks.)
1138 * ----------------------------------------------------------------
1141 ExecSelect(TupleTableSlot *slot,
1142 DestReceiver *destfunc,
1149 * get the heap tuple out of the tuple table slot
1152 attrtype = slot->ttc_tupleDescriptor;
1155 * insert the tuple into the "into relation"
1157 if (estate->es_into_relation_descriptor != NULL)
1159 heap_insert(estate->es_into_relation_descriptor, tuple,
1160 estate->es_snapshot->curcid);
1165 * send the tuple to the front end (or the screen)
1167 (*destfunc->receiveTuple) (tuple, attrtype, destfunc);
1169 (estate->es_processed)++;
1172 /* ----------------------------------------------------------------
1175 * INSERTs are trickier.. we have to insert the tuple into
1176 * the base relation and insert appropriate tuples into the
1178 * ----------------------------------------------------------------
1181 ExecInsert(TupleTableSlot *slot,
1182 ItemPointer tupleid,
1186 ResultRelInfo *resultRelInfo;
1187 Relation resultRelationDesc;
1192 * get the heap tuple out of the tuple table slot
1197 * get information on the (current) result relation
1199 resultRelInfo = estate->es_result_relation_info;
1200 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1202 /* BEFORE ROW INSERT Triggers */
1203 if (resultRelInfo->ri_TrigDesc &&
1204 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1208 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1210 if (newtuple == NULL) /* "do nothing" */
1213 if (newtuple != tuple) /* modified by Trigger(s) */
1216 * Insert modified tuple into tuple table slot, replacing the
1217 * original. We assume that it was allocated in per-tuple
1218 * memory context, and therefore will go away by itself. The
1219 * tuple table slot should not try to clear it.
1221 ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1227 * Check the constraints of the tuple
1229 if (resultRelationDesc->rd_att->constr)
1230 ExecConstraints("ExecInsert", resultRelInfo, slot, estate);
1235 newId = heap_insert(resultRelationDesc, tuple,
1236 estate->es_snapshot->curcid);
1239 (estate->es_processed)++;
1240 estate->es_lastoid = newId;
1241 setLastTid(&(tuple->t_self));
1246 * Note: heap_insert adds a new tuple to a relation. As a side effect,
1247 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1250 numIndices = resultRelInfo->ri_NumIndices;
1252 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1254 /* AFTER ROW INSERT Triggers */
1255 if (resultRelInfo->ri_TrigDesc)
1256 ExecARInsertTriggers(estate, resultRelInfo, tuple);
1259 /* ----------------------------------------------------------------
1262 * DELETE is like UPDATE, we delete the tuple and its
1264 * ----------------------------------------------------------------
1267 ExecDelete(TupleTableSlot *slot,
1268 ItemPointer tupleid,
1271 ResultRelInfo *resultRelInfo;
1272 Relation resultRelationDesc;
1273 ItemPointerData ctid;
1277 * get information on the (current) result relation
1279 resultRelInfo = estate->es_result_relation_info;
1280 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1282 /* BEFORE ROW DELETE Triggers */
1283 if (resultRelInfo->ri_TrigDesc &&
1284 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1288 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid);
1290 if (!dodelete) /* "do nothing" */
1298 result = heap_delete(resultRelationDesc, tupleid,
1300 estate->es_snapshot->curcid);
1303 case HeapTupleSelfUpdated:
1306 case HeapTupleMayBeUpdated:
1309 case HeapTupleUpdated:
1310 if (XactIsoLevel == XACT_SERIALIZABLE)
1311 elog(ERROR, "Can't serialize access due to concurrent update");
1312 else if (!(ItemPointerEquals(tupleid, &ctid)))
1314 TupleTableSlot *epqslot = EvalPlanQual(estate,
1315 resultRelInfo->ri_RangeTableIndex, &ctid);
1317 if (!TupIsNull(epqslot))
1323 /* tuple already deleted; nothing to do */
1327 elog(ERROR, "Unknown status %u from heap_delete", result);
1332 (estate->es_processed)++;
1335 * Note: Normally one would think that we have to delete index tuples
1336 * associated with the heap tuple now..
1338 * ... but in POSTGRES, we have no need to do this because the vacuum
1339 * daemon automatically opens an index scan and deletes index tuples
1340 * when it finds deleted heap tuples. -cim 9/27/89
1343 /* AFTER ROW DELETE Triggers */
1344 if (resultRelInfo->ri_TrigDesc)
1345 ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1348 /* ----------------------------------------------------------------
1351 * note: we can't run UPDATE queries with transactions
1352 * off because UPDATEs are actually INSERTs and our
1353 * scan will mistakenly loop forever, updating the tuple
1354 * it just inserted.. This should be fixed but until it
1355 * is, we don't want to get stuck in an infinite loop
1356 * which corrupts your database..
1357 * ----------------------------------------------------------------
1360 ExecUpdate(TupleTableSlot *slot,
1361 ItemPointer tupleid,
1365 ResultRelInfo *resultRelInfo;
1366 Relation resultRelationDesc;
1367 ItemPointerData ctid;
1372 * abort the operation if not running transactions
1374 if (IsBootstrapProcessingMode())
1376 elog(WARNING, "ExecUpdate: UPDATE can't run without transactions");
1381 * get the heap tuple out of the tuple table slot
1386 * get information on the (current) result relation
1388 resultRelInfo = estate->es_result_relation_info;
1389 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1391 /* BEFORE ROW UPDATE Triggers */
1392 if (resultRelInfo->ri_TrigDesc &&
1393 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1397 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1400 if (newtuple == NULL) /* "do nothing" */
1403 if (newtuple != tuple) /* modified by Trigger(s) */
1406 * Insert modified tuple into tuple table slot, replacing the
1407 * original. We assume that it was allocated in per-tuple
1408 * memory context, and therefore will go away by itself. The
1409 * tuple table slot should not try to clear it.
1411 ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1417 * Check the constraints of the tuple
1419 * If we generate a new candidate tuple after EvalPlanQual testing, we
1420 * must loop back here and recheck constraints. (We don't need to
1421 * redo triggers, however. If there are any BEFORE triggers then
1422 * trigger.c will have done mark4update to lock the correct tuple, so
1423 * there's no need to do them again.)
1426 if (resultRelationDesc->rd_att->constr)
1427 ExecConstraints("ExecUpdate", resultRelInfo, slot, estate);
1430 * replace the heap tuple
1432 result = heap_update(resultRelationDesc, tupleid, tuple,
1434 estate->es_snapshot->curcid);
1437 case HeapTupleSelfUpdated:
1440 case HeapTupleMayBeUpdated:
1443 case HeapTupleUpdated:
1444 if (XactIsoLevel == XACT_SERIALIZABLE)
1445 elog(ERROR, "Can't serialize access due to concurrent update");
1446 else if (!(ItemPointerEquals(tupleid, &ctid)))
1448 TupleTableSlot *epqslot = EvalPlanQual(estate,
1449 resultRelInfo->ri_RangeTableIndex, &ctid);
1451 if (!TupIsNull(epqslot))
1454 tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1455 slot = ExecStoreTuple(tuple,
1456 estate->es_junkFilter->jf_resultSlot,
1457 InvalidBuffer, true);
1461 /* tuple already deleted; nothing to do */
1465 elog(ERROR, "Unknown status %u from heap_update", result);
1470 (estate->es_processed)++;
1473 * Note: instead of having to update the old index tuples associated
1474 * with the heap tuple, all we do is form and insert new index tuples.
1475 * This is because UPDATEs are actually DELETEs and INSERTs and index
1476 * tuple deletion is done automagically by the vacuum daemon. All we
1477 * do is insert new index tuples. -cim 9/27/89
1483 * heap_update updates a tuple in the base relation by invalidating it
1484 * and then inserting a new tuple to the relation. As a side effect,
1485 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1486 * field. So we now insert index tuples using the new tupleid stored
1490 numIndices = resultRelInfo->ri_NumIndices;
1492 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1494 /* AFTER ROW UPDATE Triggers */
1495 if (resultRelInfo->ri_TrigDesc)
1496 ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1500 ExecRelCheck(ResultRelInfo *resultRelInfo,
1501 TupleTableSlot *slot, EState *estate)
1503 Relation rel = resultRelInfo->ri_RelationDesc;
1504 int ncheck = rel->rd_att->constr->num_check;
1505 ConstrCheck *check = rel->rd_att->constr->check;
1506 ExprContext *econtext;
1507 MemoryContext oldContext;
1512 * If first time through for this result relation, build expression
1513 * nodetrees for rel's constraint expressions. Keep them in the
1514 * per-query memory context so they'll survive throughout the query.
1516 if (resultRelInfo->ri_ConstraintExprs == NULL)
1518 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1519 resultRelInfo->ri_ConstraintExprs =
1520 (List **) palloc(ncheck * sizeof(List *));
1521 for (i = 0; i < ncheck; i++)
1523 qual = (List *) stringToNode(check[i].ccbin);
1524 resultRelInfo->ri_ConstraintExprs[i] = qual;
1526 MemoryContextSwitchTo(oldContext);
1530 * We will use the EState's per-tuple context for evaluating
1531 * constraint expressions (creating it if it's not already there).
1533 econtext = GetPerTupleExprContext(estate);
1535 /* Arrange for econtext's scan tuple to be the tuple under test */
1536 econtext->ecxt_scantuple = slot;
1538 /* And evaluate the constraints */
1539 for (i = 0; i < ncheck; i++)
1541 qual = resultRelInfo->ri_ConstraintExprs[i];
1544 * NOTE: SQL92 specifies that a NULL result from a constraint
1545 * expression is not to be treated as a failure. Therefore, tell
1546 * ExecQual to return TRUE for NULL.
1548 if (!ExecQual(qual, econtext, true))
1549 return check[i].ccname;
1552 /* NULL result means no error */
1553 return (char *) NULL;
1557 ExecConstraints(const char *caller, ResultRelInfo *resultRelInfo,
1558 TupleTableSlot *slot, EState *estate)
1560 Relation rel = resultRelInfo->ri_RelationDesc;
1561 HeapTuple tuple = slot->val;
1562 TupleConstr *constr = rel->rd_att->constr;
1566 if (constr->has_not_null)
1568 int natts = rel->rd_att->natts;
1571 for (attrChk = 1; attrChk <= natts; attrChk++)
1573 if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1574 heap_attisnull(tuple, attrChk))
1575 elog(ERROR, "%s: Fail to add null value in not null attribute %s",
1576 caller, NameStr(rel->rd_att->attrs[attrChk - 1]->attname));
1580 if (constr->num_check > 0)
1584 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1585 elog(ERROR, "%s: rejected due to CHECK constraint %s",
1591 * Check a modified tuple to see if we want to process its updated version
1592 * under READ COMMITTED rules.
1594 * See backend/executor/README for some info about how this works.
1597 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1602 HeapTupleData tuple;
1603 HeapTuple copyTuple = NULL;
1610 * find relation containing target tuple
1612 if (estate->es_result_relation_info != NULL &&
1613 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1614 relation = estate->es_result_relation_info->ri_RelationDesc;
1620 foreach(l, estate->es_rowMark)
1622 if (((execRowMark *) lfirst(l))->rti == rti)
1624 relation = ((execRowMark *) lfirst(l))->relation;
1628 if (relation == NULL)
1629 elog(ERROR, "EvalPlanQual: can't find RTE %d", (int) rti);
1635 * Loop here to deal with updated or busy tuples
1637 tuple.t_self = *tid;
1642 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1644 TransactionId xwait = SnapshotDirty->xmax;
1646 if (TransactionIdIsValid(SnapshotDirty->xmin))
1647 elog(ERROR, "EvalPlanQual: t_xmin is uncommitted ?!");
1650 * If tuple is being updated by other transaction then we have
1651 * to wait for its commit/abort.
1653 if (TransactionIdIsValid(xwait))
1655 ReleaseBuffer(buffer);
1656 XactLockTableWait(xwait);
1661 * We got tuple - now copy it for use by recheck query.
1663 copyTuple = heap_copytuple(&tuple);
1664 ReleaseBuffer(buffer);
1669 * Oops! Invalid tuple. Have to check is it updated or deleted.
1670 * Note that it's possible to get invalid SnapshotDirty->tid if
1671 * tuple updated by this transaction. Have we to check this ?
1673 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1674 !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1676 /* updated, so look at the updated copy */
1677 tuple.t_self = SnapshotDirty->tid;
1682 * Deleted or updated by this transaction; forget it.
1688 * For UPDATE/DELETE we have to return tid of actual row we're
1691 *tid = tuple.t_self;
1694 * Need to run a recheck subquery. Find or create a PQ stack entry.
1696 epq = (evalPlanQual *) estate->es_evalPlanQual;
1697 rtsize = length(estate->es_range_table);
1700 if (epq != NULL && epq->rti == 0)
1702 /* Top PQ stack entry is idle, so re-use it */
1703 Assert(!(estate->es_useEvalPlan) &&
1704 epq->estate.es_evalPlanQual == NULL);
1710 * If this is request for another RTE - Ra, - then we have to check
1711 * wasn't PlanQual requested for Ra already and if so then Ra' row was
1712 * updated again and we have to re-start old execution for Ra and
1713 * forget all what we done after Ra was suspended. Cool? -:))
1715 if (epq != NULL && epq->rti != rti &&
1716 epq->estate.es_evTuple[rti - 1] != NULL)
1720 evalPlanQual *oldepq;
1722 /* pop previous PlanQual from the stack */
1723 epqstate = &(epq->estate);
1724 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1725 Assert(oldepq->rti != 0);
1726 /* stop execution */
1727 ExecEndNode(epq->plan, NULL);
1728 ExecDropTupleTable(epqstate->es_tupleTable, true);
1729 epqstate->es_tupleTable = NULL;
1730 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1731 epqstate->es_evTuple[epq->rti - 1] = NULL;
1732 /* push current PQ to freePQ stack */
1735 estate->es_evalPlanQual = (Pointer) epq;
1736 } while (epq->rti != rti);
1740 * If we are requested for another RTE then we have to suspend
1741 * execution of current PlanQual and start execution for new one.
1743 if (epq == NULL || epq->rti != rti)
1745 /* try to reuse plan used previously */
1746 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1748 if (newepq == NULL) /* first call or freePQ stack is empty */
1750 newepq = (evalPlanQual *) palloc(sizeof(evalPlanQual));
1751 newepq->free = NULL;
1754 * Each stack level has its own copy of the plan tree. This
1755 * is wasteful, but necessary as long as plan nodes point to
1756 * exec state nodes rather than vice versa. Note that
1757 * copyfuncs.c doesn't attempt to copy the exec state nodes,
1758 * which is a good thing in this situation.
1760 newepq->plan = copyObject(estate->es_origPlan);
1763 * Init stack level's EState. We share top level's copy of
1764 * es_result_relations array and other non-changing status. We
1765 * need our own tupletable, es_param_exec_vals, and other
1768 epqstate = &(newepq->estate);
1769 memcpy(epqstate, estate, sizeof(EState));
1770 epqstate->es_direction = ForwardScanDirection;
1771 if (estate->es_origPlan->nParamExec > 0)
1772 epqstate->es_param_exec_vals = (ParamExecData *)
1773 palloc(estate->es_origPlan->nParamExec *
1774 sizeof(ParamExecData));
1775 epqstate->es_tupleTable = NULL;
1776 epqstate->es_per_tuple_exprcontext = NULL;
1779 * Each epqstate must have its own es_evTupleNull state, but
1780 * all the stack entries share es_evTuple state. This allows
1781 * sub-rechecks to inherit the value being examined by an
1784 epqstate->es_evTupleNull = (bool *) palloc(rtsize * sizeof(bool));
1787 /* first PQ stack entry */
1788 epqstate->es_evTuple = (HeapTuple *)
1789 palloc(rtsize * sizeof(HeapTuple));
1790 memset(epqstate->es_evTuple, 0, rtsize * sizeof(HeapTuple));
1794 /* later stack entries share the same storage */
1795 epqstate->es_evTuple = epq->estate.es_evTuple;
1800 /* recycle previously used EState */
1801 epqstate = &(newepq->estate);
1803 /* push current PQ to the stack */
1804 epqstate->es_evalPlanQual = (Pointer) epq;
1806 estate->es_evalPlanQual = (Pointer) epq;
1811 Assert(epq->rti == rti);
1812 epqstate = &(epq->estate);
1815 * Ok - we're requested for the same RTE. Unfortunately we still have
1816 * to end and restart execution of the plan, because ExecReScan
1817 * wouldn't ensure that upper plan nodes would reset themselves. We
1818 * could make that work if insertion of the target tuple were
1819 * integrated with the Param mechanism somehow, so that the upper plan
1820 * nodes know that their children's outputs have changed.
1824 /* stop execution */
1825 ExecEndNode(epq->plan, NULL);
1826 ExecDropTupleTable(epqstate->es_tupleTable, true);
1827 epqstate->es_tupleTable = NULL;
1831 * free old RTE' tuple, if any, and store target tuple where
1832 * relation's scan node will see it
1834 if (epqstate->es_evTuple[rti - 1] != NULL)
1835 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1836 epqstate->es_evTuple[rti - 1] = copyTuple;
1839 * Initialize for new recheck query; be careful to copy down state
1840 * that might have changed in top EState.
1842 epqstate->es_result_relation_info = estate->es_result_relation_info;
1843 epqstate->es_junkFilter = estate->es_junkFilter;
1844 if (estate->es_origPlan->nParamExec > 0)
1845 memset(epqstate->es_param_exec_vals, 0,
1846 estate->es_origPlan->nParamExec * sizeof(ParamExecData));
1847 memset(epqstate->es_evTupleNull, false, rtsize * sizeof(bool));
1848 epqstate->es_useEvalPlan = false;
1849 Assert(epqstate->es_tupleTable == NULL);
1850 epqstate->es_tupleTable =
1851 ExecCreateTupleTable(estate->es_tupleTable->size);
1853 ExecInitNode(epq->plan, epqstate, NULL);
1855 return EvalPlanQualNext(estate);
1858 static TupleTableSlot *
1859 EvalPlanQualNext(EState *estate)
1861 evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1862 EState *epqstate = &(epq->estate);
1863 evalPlanQual *oldepq;
1864 TupleTableSlot *slot;
1866 Assert(epq->rti != 0);
1869 slot = ExecProcNode(epq->plan, NULL);
1872 * No more tuples for this PQ. Continue previous one.
1874 if (TupIsNull(slot))
1876 /* stop execution */
1877 ExecEndNode(epq->plan, NULL);
1878 ExecDropTupleTable(epqstate->es_tupleTable, true);
1879 epqstate->es_tupleTable = NULL;
1880 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1881 epqstate->es_evTuple[epq->rti - 1] = NULL;
1882 /* pop old PQ from the stack */
1883 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1884 if (oldepq == (evalPlanQual *) NULL)
1886 epq->rti = 0; /* this is the first (oldest) */
1887 estate->es_useEvalPlan = false; /* PQ - mark as free and */
1888 return (NULL); /* continue Query execution */
1890 Assert(oldepq->rti != 0);
1891 /* push current PQ to freePQ stack */
1894 epqstate = &(epq->estate);
1895 estate->es_evalPlanQual = (Pointer) epq;
1903 EndEvalPlanQual(EState *estate)
1905 evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1906 EState *epqstate = &(epq->estate);
1907 evalPlanQual *oldepq;
1909 if (epq->rti == 0) /* plans already shutdowned */
1911 Assert(epq->estate.es_evalPlanQual == NULL);
1917 /* stop execution */
1918 ExecEndNode(epq->plan, NULL);
1919 ExecDropTupleTable(epqstate->es_tupleTable, true);
1920 epqstate->es_tupleTable = NULL;
1921 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1923 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1924 epqstate->es_evTuple[epq->rti - 1] = NULL;
1926 /* pop old PQ from the stack */
1927 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1928 if (oldepq == (evalPlanQual *) NULL)
1930 epq->rti = 0; /* this is the first (oldest) */
1931 estate->es_useEvalPlan = false; /* PQ - mark as free */
1934 Assert(oldepq->rti != 0);
1935 /* push current PQ to freePQ stack */
1938 epqstate = &(epq->estate);
1939 estate->es_evalPlanQual = (Pointer) epq;