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11 * The old ExecutorMain() has been replaced by ExecutorStart(),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) 1996-2001, 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 1.157 2002/04/08 22:42:18 momjian Exp $
32 *-------------------------------------------------------------------------
36 #include "access/heapam.h"
37 #include "catalog/heap.h"
38 #include "catalog/namespace.h"
39 #include "commands/command.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 ExecRetrieve(TupleTableSlot *slot,
66 DestReceiver *destfunc,
68 static void ExecAppend(TupleTableSlot *slot, ItemPointer tupleid,
70 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
72 static void ExecReplace(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 queries snapshot data
119 if (QuerySnapshot == NULL)
120 estate->es_snapshot = NULL;
123 estate->es_snapshot = (Snapshot) palloc(sizeof(SnapshotData));
124 memcpy(estate->es_snapshot, QuerySnapshot, sizeof(SnapshotData));
125 if (estate->es_snapshot->xcnt > 0)
127 estate->es_snapshot->xip = (TransactionId *)
128 palloc(estate->es_snapshot->xcnt * sizeof(TransactionId));
129 memcpy(estate->es_snapshot->xip, QuerySnapshot->xip,
130 estate->es_snapshot->xcnt * sizeof(TransactionId));
135 * Initialize the plan
137 result = InitPlan(queryDesc->operation,
138 queryDesc->parsetree,
142 queryDesc->tupDesc = result;
147 /* ----------------------------------------------------------------
150 * This is the main routine of the executor module. It accepts
151 * the query descriptor from the traffic cop and executes the
154 * ExecutorStart must have been called already.
156 * If direction is NoMovementScanDirection then nothing is done
157 * except to start up/shut down the destination. Otherwise,
158 * we retrieve up to 'count' tuples in the specified direction.
160 * Note: count = 0 is interpreted as no portal limit, e.g. run to
163 * ----------------------------------------------------------------
166 ExecutorRun(QueryDesc *queryDesc, EState *estate,
167 ScanDirection direction, long count)
172 DestReceiver *destfunc;
173 TupleTableSlot *result;
178 Assert(queryDesc != NULL);
181 * extract information from the query descriptor and the query
184 operation = queryDesc->operation;
185 plan = queryDesc->plantree;
186 dest = queryDesc->dest;
189 * startup tuple receiver
191 estate->es_processed = 0;
192 estate->es_lastoid = InvalidOid;
194 destfunc = DestToFunction(dest);
195 (*destfunc->setup) (destfunc, (int) operation,
196 queryDesc->portalName, queryDesc->tupDesc);
201 if (direction == NoMovementScanDirection)
204 result = ExecutePlan(estate,
214 (*destfunc->cleanup) (destfunc);
219 /* ----------------------------------------------------------------
222 * This routine must be called at the end of execution of any
224 * ----------------------------------------------------------------
227 ExecutorEnd(QueryDesc *queryDesc, EState *estate)
230 Assert(queryDesc != NULL);
232 EndPlan(queryDesc->plantree, estate);
234 if (estate->es_snapshot != NULL)
236 if (estate->es_snapshot->xcnt > 0)
237 pfree(estate->es_snapshot->xip);
238 pfree(estate->es_snapshot);
239 estate->es_snapshot = NULL;
242 if (estate->es_param_exec_vals != NULL)
244 pfree(estate->es_param_exec_vals);
245 estate->es_param_exec_vals = NULL;
251 * ExecCheckQueryPerms
252 * Check access permissions for all relations referenced in a query.
255 ExecCheckQueryPerms(CmdType operation, Query *parseTree, Plan *plan)
258 * Check RTEs in the query's primary rangetable.
260 ExecCheckRTPerms(parseTree->rtable, operation);
263 * Search for subplans and APPEND nodes to check their rangetables.
265 ExecCheckPlanPerms(plan, parseTree->rtable, operation);
270 * Recursively scan the plan tree to check access permissions in
274 ExecCheckPlanPerms(Plan *plan, List *rangeTable, CmdType operation)
281 /* Check subplans, which we assume are plain SELECT queries */
283 foreach(subp, plan->initPlan)
285 SubPlan *subplan = (SubPlan *) lfirst(subp);
287 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
288 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
290 foreach(subp, plan->subPlan)
292 SubPlan *subplan = (SubPlan *) lfirst(subp);
294 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
295 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
298 /* Check lower plan nodes */
300 ExecCheckPlanPerms(plan->lefttree, rangeTable, operation);
301 ExecCheckPlanPerms(plan->righttree, rangeTable, operation);
303 /* Do node-type-specific checks */
305 switch (nodeTag(plan))
309 SubqueryScan *scan = (SubqueryScan *) plan;
312 /* Recursively check the subquery */
313 rte = rt_fetch(scan->scan.scanrelid, rangeTable);
314 Assert(rte->subquery != NULL);
315 ExecCheckQueryPerms(operation, rte->subquery, scan->subplan);
320 Append *app = (Append *) plan;
323 foreach(appendplans, app->appendplans)
325 ExecCheckPlanPerms((Plan *) lfirst(appendplans),
339 * Check access permissions for all relations listed in a range table.
342 ExecCheckRTPerms(List *rangeTable, CmdType operation)
346 foreach(lp, rangeTable)
348 RangeTblEntry *rte = lfirst(lp);
350 ExecCheckRTEPerms(rte, operation);
356 * Check access permissions for a single RTE.
359 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
363 int32 aclcheck_result;
366 * If it's a subquery RTE, ignore it --- it will be checked when
367 * ExecCheckPlanPerms finds the SubqueryScan node for it.
369 if (rte->rtekind != RTE_RELATION)
375 * userid to check as: current user unless we have a setuid
378 * Note: GetUserId() is presently fast enough that there's no harm in
379 * calling it separately for each RTE. If that stops being true, we
380 * could call it once in ExecCheckQueryPerms and pass the userid down
381 * from there. But for now, no need for the extra clutter.
383 userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
385 #define CHECK(MODE) pg_class_aclcheck(relOid, userid, MODE)
387 if (rte->checkForRead)
389 aclcheck_result = CHECK(ACL_SELECT);
390 if (aclcheck_result != ACLCHECK_OK)
391 elog(ERROR, "%s: %s",
392 get_rel_name(relOid),
393 aclcheck_error_strings[aclcheck_result]);
396 if (rte->checkForWrite)
399 * Note: write access in a SELECT context means SELECT FOR UPDATE.
400 * Right now we don't distinguish that from true update as far as
401 * permissions checks are concerned.
406 aclcheck_result = CHECK(ACL_INSERT);
410 aclcheck_result = CHECK(ACL_UPDATE);
413 aclcheck_result = CHECK(ACL_DELETE);
416 elog(ERROR, "ExecCheckRTEPerms: bogus operation %d",
418 aclcheck_result = ACLCHECK_OK; /* keep compiler quiet */
421 if (aclcheck_result != ACLCHECK_OK)
422 elog(ERROR, "%s: %s",
423 get_rel_name(relOid),
424 aclcheck_error_strings[aclcheck_result]);
429 /* ===============================================================
430 * ===============================================================
431 static routines follow
432 * ===============================================================
433 * ===============================================================
436 typedef struct execRowMark
443 typedef struct evalPlanQual
448 struct evalPlanQual *free;
451 /* ----------------------------------------------------------------
454 * Initializes the query plan: open files, allocate storage
455 * and start up the rule manager
456 * ----------------------------------------------------------------
459 InitPlan(CmdType operation, Query *parseTree, Plan *plan, EState *estate)
462 Relation intoRelationDesc;
466 * Do permissions checks.
468 ExecCheckQueryPerms(operation, parseTree, plan);
471 * get information from query descriptor
473 rangeTable = parseTree->rtable;
476 * initialize the node's execution state
478 estate->es_range_table = rangeTable;
481 * if there is a result relation, initialize result relation stuff
483 if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
485 List *resultRelations = parseTree->resultRelations;
486 int numResultRelations;
487 ResultRelInfo *resultRelInfos;
489 if (resultRelations != NIL)
492 * Multiple result relations (due to inheritance)
493 * parseTree->resultRelations identifies them all
495 ResultRelInfo *resultRelInfo;
497 numResultRelations = length(resultRelations);
498 resultRelInfos = (ResultRelInfo *)
499 palloc(numResultRelations * sizeof(ResultRelInfo));
500 resultRelInfo = resultRelInfos;
501 while (resultRelations != NIL)
503 initResultRelInfo(resultRelInfo,
504 lfirsti(resultRelations),
508 resultRelations = lnext(resultRelations);
514 * Single result relation identified by
515 * parseTree->resultRelation
517 numResultRelations = 1;
518 resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
519 initResultRelInfo(resultRelInfos,
520 parseTree->resultRelation,
525 estate->es_result_relations = resultRelInfos;
526 estate->es_num_result_relations = numResultRelations;
527 /* Initialize to first or only result rel */
528 estate->es_result_relation_info = resultRelInfos;
533 * if no result relation, then set state appropriately
535 estate->es_result_relations = NULL;
536 estate->es_num_result_relations = 0;
537 estate->es_result_relation_info = NULL;
541 * Have to lock relations selected for update
543 estate->es_rowMark = NIL;
544 if (parseTree->rowMarks != NIL)
548 foreach(l, parseTree->rowMarks)
550 Index rti = lfirsti(l);
551 Oid relid = getrelid(rti, rangeTable);
555 relation = heap_open(relid, RowShareLock);
556 erm = (execRowMark *) palloc(sizeof(execRowMark));
557 erm->relation = relation;
559 sprintf(erm->resname, "ctid%u", rti);
560 estate->es_rowMark = lappend(estate->es_rowMark, erm);
565 * initialize the executor "tuple" table. We need slots for all the
566 * plan nodes, plus possibly output slots for the junkfilter(s). At
567 * this point we aren't sure if we need junkfilters, so just add slots
568 * for them unconditionally.
571 int nSlots = ExecCountSlotsNode(plan);
573 if (parseTree->resultRelations != NIL)
574 nSlots += length(parseTree->resultRelations);
577 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
580 /* mark EvalPlanQual not active */
581 estate->es_origPlan = plan;
582 estate->es_evalPlanQual = NULL;
583 estate->es_evTuple = NULL;
584 estate->es_evTupleNull = NULL;
585 estate->es_useEvalPlan = false;
588 * initialize the private state information for all the nodes in the
589 * query tree. This opens files, allocates storage and leaves us
590 * ready to start processing tuples.
592 ExecInitNode(plan, estate, NULL);
595 * Get the tuple descriptor describing the type of tuples to return.
596 * (this is especially important if we are creating a relation with
599 tupType = ExecGetTupType(plan); /* tuple descriptor */
602 * Initialize the junk filter if needed. SELECT and INSERT queries
603 * need a filter if there are any junk attrs in the tlist. UPDATE and
604 * DELETE always need one, since there's always a junk 'ctid'
605 * attribute present --- no need to look first.
608 bool junk_filter_needed = false;
615 foreach(tlist, plan->targetlist)
617 TargetEntry *tle = (TargetEntry *) lfirst(tlist);
619 if (tle->resdom->resjunk)
621 junk_filter_needed = true;
628 junk_filter_needed = true;
634 if (junk_filter_needed)
637 * If there are multiple result relations, each one needs its
638 * own junk filter. Note this is only possible for
639 * UPDATE/DELETE, so we can't be fooled by some needing a
640 * filter and some not.
642 if (parseTree->resultRelations != NIL)
645 ResultRelInfo *resultRelInfo;
647 /* Top plan had better be an Append here. */
648 Assert(IsA(plan, Append));
649 Assert(((Append *) plan)->isTarget);
650 subplans = ((Append *) plan)->appendplans;
651 Assert(length(subplans) == estate->es_num_result_relations);
652 resultRelInfo = estate->es_result_relations;
653 while (subplans != NIL)
655 Plan *subplan = (Plan *) lfirst(subplans);
658 j = ExecInitJunkFilter(subplan->targetlist,
659 ExecGetTupType(subplan),
660 ExecAllocTableSlot(estate->es_tupleTable));
661 resultRelInfo->ri_junkFilter = j;
663 subplans = lnext(subplans);
667 * Set active junkfilter too; at this point ExecInitAppend
668 * has already selected an active result relation...
670 estate->es_junkFilter =
671 estate->es_result_relation_info->ri_junkFilter;
675 /* Normal case with just one JunkFilter */
678 j = ExecInitJunkFilter(plan->targetlist,
680 ExecAllocTableSlot(estate->es_tupleTable));
681 estate->es_junkFilter = j;
682 if (estate->es_result_relation_info)
683 estate->es_result_relation_info->ri_junkFilter = j;
685 /* For SELECT, want to return the cleaned tuple type */
686 if (operation == CMD_SELECT)
687 tupType = j->jf_cleanTupType;
691 estate->es_junkFilter = NULL;
695 * initialize the "into" relation
697 intoRelationDesc = (Relation) NULL;
699 if (operation == CMD_SELECT)
701 if (!parseTree->isPortal)
704 * a select into table
706 if (parseTree->into != NULL)
714 * create the "into" relation
716 intoName = parseTree->into->relname;
717 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
720 * have to copy tupType to get rid of constraints
722 tupdesc = CreateTupleDescCopy(tupType);
725 heap_create_with_catalog(intoName,
730 allowSystemTableMods);
732 FreeTupleDesc(tupdesc);
735 * Advance command counter so that the newly-created
736 * relation's catalog tuples will be visible to heap_open.
738 CommandCounterIncrement();
741 * If necessary, create a TOAST table for the into
742 * relation. Note that AlterTableCreateToastTable ends
743 * with CommandCounterIncrement(), so that the TOAST table
744 * will be visible for insertion.
746 AlterTableCreateToastTable(intoRelationId, true);
748 intoRelationDesc = heap_open(intoRelationId,
749 AccessExclusiveLock);
754 estate->es_into_relation_descriptor = intoRelationDesc;
760 * Initialize ResultRelInfo data for one result relation
763 initResultRelInfo(ResultRelInfo *resultRelInfo,
764 Index resultRelationIndex,
768 Oid resultRelationOid;
769 Relation resultRelationDesc;
771 resultRelationOid = getrelid(resultRelationIndex, rangeTable);
772 resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
774 switch (resultRelationDesc->rd_rel->relkind)
776 case RELKIND_SEQUENCE:
777 elog(ERROR, "You can't change sequence relation %s",
778 RelationGetRelationName(resultRelationDesc));
780 case RELKIND_TOASTVALUE:
781 elog(ERROR, "You can't change toast relation %s",
782 RelationGetRelationName(resultRelationDesc));
785 elog(ERROR, "You can't change view relation %s",
786 RelationGetRelationName(resultRelationDesc));
790 MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
791 resultRelInfo->type = T_ResultRelInfo;
792 resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
793 resultRelInfo->ri_RelationDesc = resultRelationDesc;
794 resultRelInfo->ri_NumIndices = 0;
795 resultRelInfo->ri_IndexRelationDescs = NULL;
796 resultRelInfo->ri_IndexRelationInfo = NULL;
797 resultRelInfo->ri_TrigDesc = resultRelationDesc->trigdesc;
798 resultRelInfo->ri_TrigFunctions = NULL;
799 resultRelInfo->ri_ConstraintExprs = NULL;
800 resultRelInfo->ri_junkFilter = NULL;
803 * If there are indices on the result relation, open them and save
804 * descriptors in the result relation info, so that we can add new
805 * index entries for the tuples we add/update. We need not do this
806 * for a DELETE, however, since deletion doesn't affect indexes.
808 if (resultRelationDesc->rd_rel->relhasindex &&
809 operation != CMD_DELETE)
810 ExecOpenIndices(resultRelInfo);
813 /* ----------------------------------------------------------------
816 * Cleans up the query plan -- closes files and free up storages
817 * ----------------------------------------------------------------
820 EndPlan(Plan *plan, EState *estate)
822 ResultRelInfo *resultRelInfo;
827 * shut down any PlanQual processing we were doing
829 if (estate->es_evalPlanQual != NULL)
830 EndEvalPlanQual(estate);
833 * shut down the node-type-specific query processing
835 ExecEndNode(plan, NULL);
838 * destroy the executor "tuple" table.
840 ExecDropTupleTable(estate->es_tupleTable, true);
841 estate->es_tupleTable = NULL;
844 * close the result relation(s) if any, but hold locks until xact
845 * commit. Also clean up junkfilters if present.
847 resultRelInfo = estate->es_result_relations;
848 for (i = estate->es_num_result_relations; i > 0; i--)
850 /* Close indices and then the relation itself */
851 ExecCloseIndices(resultRelInfo);
852 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
853 /* Delete the junkfilter if any */
854 if (resultRelInfo->ri_junkFilter != NULL)
855 ExecFreeJunkFilter(resultRelInfo->ri_junkFilter);
860 * close the "into" relation if necessary, again keeping lock
862 if (estate->es_into_relation_descriptor != NULL)
863 heap_close(estate->es_into_relation_descriptor, NoLock);
866 * There might be a junkfilter without a result relation.
868 if (estate->es_num_result_relations == 0 &&
869 estate->es_junkFilter != NULL)
871 ExecFreeJunkFilter(estate->es_junkFilter);
872 estate->es_junkFilter = NULL;
876 * close any relations selected FOR UPDATE, again keeping locks
878 foreach(l, estate->es_rowMark)
880 execRowMark *erm = lfirst(l);
882 heap_close(erm->relation, NoLock);
886 /* ----------------------------------------------------------------
889 * processes the query plan to retrieve 'numberTuples' tuples in the
890 * direction specified.
891 * Retrieves all tuples if numberTuples is 0
893 * result is either a slot containing the last tuple in the case
894 * of a RETRIEVE or NULL otherwise.
896 * Note: the ctid attribute is a 'junk' attribute that is removed before the
898 * ----------------------------------------------------------------
900 static TupleTableSlot *
901 ExecutePlan(EState *estate,
905 ScanDirection direction,
906 DestReceiver *destfunc)
908 JunkFilter *junkfilter;
909 TupleTableSlot *slot;
910 ItemPointer tupleid = NULL;
911 ItemPointerData tuple_ctid;
912 long current_tuple_count;
913 TupleTableSlot *result;
916 * initialize local variables
919 current_tuple_count = 0;
925 estate->es_direction = direction;
928 * Loop until we've processed the proper number of tuples from the
934 /* Reset the per-output-tuple exprcontext */
935 ResetPerTupleExprContext(estate);
938 * Execute the plan and obtain a tuple
941 if (estate->es_useEvalPlan)
943 slot = EvalPlanQualNext(estate);
945 slot = ExecProcNode(plan, NULL);
948 slot = ExecProcNode(plan, NULL);
951 * if the tuple is null, then we assume there is nothing more to
952 * process so we just return null...
961 * if we have a junk filter, then project a new tuple with the
964 * Store this new "clean" tuple in the junkfilter's resultSlot.
965 * (Formerly, we stored it back over the "dirty" tuple, which is
966 * WRONG because that tuple slot has the wrong descriptor.)
968 * Also, extract all the junk information we need.
970 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
977 * extract the 'ctid' junk attribute.
979 if (operation == CMD_UPDATE || operation == CMD_DELETE)
981 if (!ExecGetJunkAttribute(junkfilter,
986 elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
988 /* shouldn't ever get a null result... */
990 elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
992 tupleid = (ItemPointer) DatumGetPointer(datum);
993 tuple_ctid = *tupleid; /* make sure we don't free the
995 tupleid = &tuple_ctid;
997 else if (estate->es_rowMark != NIL)
1002 foreach(l, estate->es_rowMark)
1004 execRowMark *erm = lfirst(l);
1006 HeapTupleData tuple;
1007 TupleTableSlot *newSlot;
1010 if (!ExecGetJunkAttribute(junkfilter,
1015 elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
1018 /* shouldn't ever get a null result... */
1020 elog(ERROR, "ExecutePlan: (junk) `%s' is NULL!",
1023 tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1024 test = heap_mark4update(erm->relation, &tuple, &buffer);
1025 ReleaseBuffer(buffer);
1028 case HeapTupleSelfUpdated:
1029 case HeapTupleMayBeUpdated:
1032 case HeapTupleUpdated:
1033 if (XactIsoLevel == XACT_SERIALIZABLE)
1034 elog(ERROR, "Can't serialize access due to concurrent update");
1035 if (!(ItemPointerEquals(&(tuple.t_self),
1036 (ItemPointer) DatumGetPointer(datum))))
1038 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1039 if (!(TupIsNull(newSlot)))
1042 estate->es_useEvalPlan = true;
1048 * if tuple was deleted or PlanQual failed for
1049 * updated tuple - we must not return this
1055 elog(ERROR, "Unknown status %u from heap_mark4update", test);
1062 * Finally create a new "clean" tuple with all junk attributes
1065 newTuple = ExecRemoveJunk(junkfilter, slot);
1067 slot = ExecStoreTuple(newTuple, /* tuple to store */
1068 junkfilter->jf_resultSlot, /* dest slot */
1069 InvalidBuffer, /* this tuple has no
1071 true); /* tuple should be pfreed */
1072 } /* if (junkfilter... */
1075 * now that we have a tuple, do the appropriate thing with it..
1076 * either return it to the user, add it to a relation someplace,
1077 * delete it from a relation, or modify some of its attributes.
1083 ExecRetrieve(slot, /* slot containing tuple */
1084 destfunc, /* destination's tuple-receiver
1091 ExecAppend(slot, tupleid, estate);
1096 ExecDelete(slot, tupleid, estate);
1101 ExecReplace(slot, tupleid, estate);
1106 elog(LOG, "ExecutePlan: unknown operation in queryDesc");
1112 * check our tuple count.. if we've processed the proper number
1113 * then quit, else loop again and process more tuples..
1115 current_tuple_count++;
1116 if (numberTuples == current_tuple_count)
1121 * here, result is either a slot containing a tuple in the case of a
1122 * RETRIEVE or NULL otherwise.
1127 /* ----------------------------------------------------------------
1130 * RETRIEVEs are easy.. we just pass the tuple to the appropriate
1131 * print function. The only complexity is when we do a
1132 * "retrieve into", in which case we insert the tuple into
1133 * the appropriate relation (note: this is a newly created relation
1134 * so we don't need to worry about indices or locks.)
1135 * ----------------------------------------------------------------
1138 ExecRetrieve(TupleTableSlot *slot,
1139 DestReceiver *destfunc,
1146 * get the heap tuple out of the tuple table slot
1149 attrtype = slot->ttc_tupleDescriptor;
1152 * insert the tuple into the "into relation"
1154 if (estate->es_into_relation_descriptor != NULL)
1156 heap_insert(estate->es_into_relation_descriptor, tuple);
1161 * send the tuple to the front end (or the screen)
1163 (*destfunc->receiveTuple) (tuple, attrtype, destfunc);
1165 (estate->es_processed)++;
1168 /* ----------------------------------------------------------------
1171 * APPENDs are trickier.. we have to insert the tuple into
1172 * the base relation and insert appropriate tuples into the
1174 * ----------------------------------------------------------------
1178 ExecAppend(TupleTableSlot *slot,
1179 ItemPointer tupleid,
1183 ResultRelInfo *resultRelInfo;
1184 Relation resultRelationDesc;
1189 * get the heap tuple out of the tuple table slot
1194 * get information on the (current) result relation
1196 resultRelInfo = estate->es_result_relation_info;
1197 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1199 /* BEFORE ROW INSERT Triggers */
1200 if (resultRelInfo->ri_TrigDesc &&
1201 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1205 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1207 if (newtuple == NULL) /* "do nothing" */
1210 if (newtuple != tuple) /* modified by Trigger(s) */
1213 * Insert modified tuple into tuple table slot, replacing the
1214 * original. We assume that it was allocated in per-tuple
1215 * memory context, and therefore will go away by itself. The
1216 * tuple table slot should not try to clear it.
1218 ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1224 * Check the constraints of the tuple
1226 if (resultRelationDesc->rd_att->constr)
1227 ExecConstraints("ExecAppend", resultRelInfo, slot, estate);
1232 newId = heap_insert(resultRelationDesc, tuple);
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 append, 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, &ctid);
1297 case HeapTupleSelfUpdated:
1300 case HeapTupleMayBeUpdated:
1303 case HeapTupleUpdated:
1304 if (XactIsoLevel == XACT_SERIALIZABLE)
1305 elog(ERROR, "Can't serialize access due to concurrent update");
1306 else if (!(ItemPointerEquals(tupleid, &ctid)))
1308 TupleTableSlot *epqslot = EvalPlanQual(estate,
1309 resultRelInfo->ri_RangeTableIndex, &ctid);
1311 if (!TupIsNull(epqslot))
1317 /* tuple already deleted; nothing to do */
1321 elog(ERROR, "Unknown status %u from heap_delete", result);
1326 (estate->es_processed)++;
1329 * Note: Normally one would think that we have to delete index tuples
1330 * associated with the heap tuple now..
1332 * ... but in POSTGRES, we have no need to do this because the vacuum
1333 * daemon automatically opens an index scan and deletes index tuples
1334 * when it finds deleted heap tuples. -cim 9/27/89
1337 /* AFTER ROW DELETE Triggers */
1338 if (resultRelInfo->ri_TrigDesc)
1339 ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1342 /* ----------------------------------------------------------------
1345 * note: we can't run replace queries with transactions
1346 * off because replaces are actually appends and our
1347 * scan will mistakenly loop forever, replacing the tuple
1348 * it just appended.. This should be fixed but until it
1349 * is, we don't want to get stuck in an infinite loop
1350 * which corrupts your database..
1351 * ----------------------------------------------------------------
1354 ExecReplace(TupleTableSlot *slot,
1355 ItemPointer tupleid,
1359 ResultRelInfo *resultRelInfo;
1360 Relation resultRelationDesc;
1361 ItemPointerData ctid;
1366 * abort the operation if not running transactions
1368 if (IsBootstrapProcessingMode())
1370 elog(WARNING, "ExecReplace: replace can't run without transactions");
1375 * get the heap tuple out of the tuple table slot
1380 * get information on the (current) result relation
1382 resultRelInfo = estate->es_result_relation_info;
1383 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1385 /* BEFORE ROW UPDATE Triggers */
1386 if (resultRelInfo->ri_TrigDesc &&
1387 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1391 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1394 if (newtuple == NULL) /* "do nothing" */
1397 if (newtuple != tuple) /* modified by Trigger(s) */
1400 * Insert modified tuple into tuple table slot, replacing the
1401 * original. We assume that it was allocated in per-tuple
1402 * memory context, and therefore will go away by itself. The
1403 * tuple table slot should not try to clear it.
1405 ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1411 * Check the constraints of the tuple
1413 * If we generate a new candidate tuple after EvalPlanQual testing, we
1414 * must loop back here and recheck constraints. (We don't need to
1415 * redo triggers, however. If there are any BEFORE triggers then
1416 * trigger.c will have done mark4update to lock the correct tuple, so
1417 * there's no need to do them again.)
1420 if (resultRelationDesc->rd_att->constr)
1421 ExecConstraints("ExecReplace", resultRelInfo, slot, estate);
1424 * replace the heap tuple
1426 result = heap_update(resultRelationDesc, tupleid, tuple, &ctid);
1429 case HeapTupleSelfUpdated:
1432 case HeapTupleMayBeUpdated:
1435 case HeapTupleUpdated:
1436 if (XactIsoLevel == XACT_SERIALIZABLE)
1437 elog(ERROR, "Can't serialize access due to concurrent update");
1438 else if (!(ItemPointerEquals(tupleid, &ctid)))
1440 TupleTableSlot *epqslot = EvalPlanQual(estate,
1441 resultRelInfo->ri_RangeTableIndex, &ctid);
1443 if (!TupIsNull(epqslot))
1446 tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1447 slot = ExecStoreTuple(tuple,
1448 estate->es_junkFilter->jf_resultSlot,
1449 InvalidBuffer, true);
1453 /* tuple already deleted; nothing to do */
1457 elog(ERROR, "Unknown status %u from heap_update", result);
1462 (estate->es_processed)++;
1465 * Note: instead of having to update the old index tuples associated
1466 * with the heap tuple, all we do is form and insert new index tuples.
1467 * This is because replaces are actually deletes and inserts and index
1468 * tuple deletion is done automagically by the vacuum daemon. All we
1469 * do is insert new index tuples. -cim 9/27/89
1475 * heap_update updates a tuple in the base relation by invalidating it
1476 * and then appending a new tuple to the relation. As a side effect,
1477 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1478 * field. So we now insert index tuples using the new tupleid stored
1482 numIndices = resultRelInfo->ri_NumIndices;
1484 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, true);
1486 /* AFTER ROW UPDATE Triggers */
1487 if (resultRelInfo->ri_TrigDesc)
1488 ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1492 ExecRelCheck(ResultRelInfo *resultRelInfo,
1493 TupleTableSlot *slot, EState *estate)
1495 Relation rel = resultRelInfo->ri_RelationDesc;
1496 int ncheck = rel->rd_att->constr->num_check;
1497 ConstrCheck *check = rel->rd_att->constr->check;
1498 ExprContext *econtext;
1499 MemoryContext oldContext;
1504 * If first time through for this result relation, build expression
1505 * nodetrees for rel's constraint expressions. Keep them in the
1506 * per-query memory context so they'll survive throughout the query.
1508 if (resultRelInfo->ri_ConstraintExprs == NULL)
1510 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1511 resultRelInfo->ri_ConstraintExprs =
1512 (List **) palloc(ncheck * sizeof(List *));
1513 for (i = 0; i < ncheck; i++)
1515 qual = (List *) stringToNode(check[i].ccbin);
1516 resultRelInfo->ri_ConstraintExprs[i] = qual;
1518 MemoryContextSwitchTo(oldContext);
1522 * We will use the EState's per-tuple context for evaluating
1523 * constraint expressions (creating it if it's not already there).
1525 econtext = GetPerTupleExprContext(estate);
1527 /* Arrange for econtext's scan tuple to be the tuple under test */
1528 econtext->ecxt_scantuple = slot;
1530 /* And evaluate the constraints */
1531 for (i = 0; i < ncheck; i++)
1533 qual = resultRelInfo->ri_ConstraintExprs[i];
1536 * NOTE: SQL92 specifies that a NULL result from a constraint
1537 * expression is not to be treated as a failure. Therefore, tell
1538 * ExecQual to return TRUE for NULL.
1540 if (!ExecQual(qual, econtext, true))
1541 return check[i].ccname;
1544 /* NULL result means no error */
1545 return (char *) NULL;
1549 ExecConstraints(char *caller, ResultRelInfo *resultRelInfo,
1550 TupleTableSlot *slot, EState *estate)
1552 Relation rel = resultRelInfo->ri_RelationDesc;
1553 HeapTuple tuple = slot->val;
1554 TupleConstr *constr = rel->rd_att->constr;
1558 if (constr->has_not_null)
1560 int natts = rel->rd_att->natts;
1563 for (attrChk = 1; attrChk <= natts; attrChk++)
1565 if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1566 heap_attisnull(tuple, attrChk))
1567 elog(ERROR, "%s: Fail to add null value in not null attribute %s",
1568 caller, NameStr(rel->rd_att->attrs[attrChk - 1]->attname));
1572 if (constr->num_check > 0)
1576 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1577 elog(ERROR, "%s: rejected due to CHECK constraint %s",
1583 * Check a modified tuple to see if we want to process its updated version
1584 * under READ COMMITTED rules.
1586 * See backend/executor/README for some info about how this works.
1589 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1594 HeapTupleData tuple;
1595 HeapTuple copyTuple = NULL;
1602 * find relation containing target tuple
1604 if (estate->es_result_relation_info != NULL &&
1605 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1606 relation = estate->es_result_relation_info->ri_RelationDesc;
1612 foreach(l, estate->es_rowMark)
1614 if (((execRowMark *) lfirst(l))->rti == rti)
1616 relation = ((execRowMark *) lfirst(l))->relation;
1620 if (relation == NULL)
1621 elog(ERROR, "EvalPlanQual: can't find RTE %d", (int) rti);
1627 * Loop here to deal with updated or busy tuples
1629 tuple.t_self = *tid;
1634 heap_fetch(relation, SnapshotDirty, &tuple, &buffer, NULL);
1635 if (tuple.t_data != NULL)
1637 TransactionId xwait = SnapshotDirty->xmax;
1639 if (TransactionIdIsValid(SnapshotDirty->xmin))
1640 elog(ERROR, "EvalPlanQual: t_xmin is uncommitted ?!");
1643 * If tuple is being updated by other transaction then we have
1644 * to wait for its commit/abort.
1646 if (TransactionIdIsValid(xwait))
1648 ReleaseBuffer(buffer);
1649 XactLockTableWait(xwait);
1654 * We got tuple - now copy it for use by recheck query.
1656 copyTuple = heap_copytuple(&tuple);
1657 ReleaseBuffer(buffer);
1662 * Oops! Invalid tuple. Have to check is it updated or deleted.
1663 * Note that it's possible to get invalid SnapshotDirty->tid if
1664 * tuple updated by this transaction. Have we to check this ?
1666 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1667 !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1669 /* updated, so look at the updated copy */
1670 tuple.t_self = SnapshotDirty->tid;
1675 * Deleted or updated by this transaction; forget it.
1681 * For UPDATE/DELETE we have to return tid of actual row we're
1684 *tid = tuple.t_self;
1687 * Need to run a recheck subquery. Find or create a PQ stack entry.
1689 epq = (evalPlanQual *) estate->es_evalPlanQual;
1690 rtsize = length(estate->es_range_table);
1693 if (epq != NULL && epq->rti == 0)
1695 /* Top PQ stack entry is idle, so re-use it */
1696 Assert(!(estate->es_useEvalPlan) &&
1697 epq->estate.es_evalPlanQual == NULL);
1703 * If this is request for another RTE - Ra, - then we have to check
1704 * wasn't PlanQual requested for Ra already and if so then Ra' row was
1705 * updated again and we have to re-start old execution for Ra and
1706 * forget all what we done after Ra was suspended. Cool? -:))
1708 if (epq != NULL && epq->rti != rti &&
1709 epq->estate.es_evTuple[rti - 1] != NULL)
1713 evalPlanQual *oldepq;
1715 /* pop previous PlanQual from the stack */
1716 epqstate = &(epq->estate);
1717 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1718 Assert(oldepq->rti != 0);
1719 /* stop execution */
1720 ExecEndNode(epq->plan, NULL);
1721 ExecDropTupleTable(epqstate->es_tupleTable, true);
1722 epqstate->es_tupleTable = NULL;
1723 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1724 epqstate->es_evTuple[epq->rti - 1] = NULL;
1725 /* push current PQ to freePQ stack */
1728 estate->es_evalPlanQual = (Pointer) epq;
1729 } while (epq->rti != rti);
1733 * If we are requested for another RTE then we have to suspend
1734 * execution of current PlanQual and start execution for new one.
1736 if (epq == NULL || epq->rti != rti)
1738 /* try to reuse plan used previously */
1739 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1741 if (newepq == NULL) /* first call or freePQ stack is empty */
1743 newepq = (evalPlanQual *) palloc(sizeof(evalPlanQual));
1744 newepq->free = NULL;
1747 * Each stack level has its own copy of the plan tree. This
1748 * is wasteful, but necessary as long as plan nodes point to
1749 * exec state nodes rather than vice versa. Note that
1750 * copyfuncs.c doesn't attempt to copy the exec state nodes,
1751 * which is a good thing in this situation.
1753 newepq->plan = copyObject(estate->es_origPlan);
1756 * Init stack level's EState. We share top level's copy of
1757 * es_result_relations array and other non-changing status. We
1758 * need our own tupletable, es_param_exec_vals, and other
1761 epqstate = &(newepq->estate);
1762 memcpy(epqstate, estate, sizeof(EState));
1763 epqstate->es_direction = ForwardScanDirection;
1764 if (estate->es_origPlan->nParamExec > 0)
1765 epqstate->es_param_exec_vals = (ParamExecData *)
1766 palloc(estate->es_origPlan->nParamExec *
1767 sizeof(ParamExecData));
1768 epqstate->es_tupleTable = NULL;
1769 epqstate->es_per_tuple_exprcontext = NULL;
1772 * Each epqstate must have its own es_evTupleNull state, but
1773 * all the stack entries share es_evTuple state. This allows
1774 * sub-rechecks to inherit the value being examined by an
1777 epqstate->es_evTupleNull = (bool *) palloc(rtsize * sizeof(bool));
1780 /* first PQ stack entry */
1781 epqstate->es_evTuple = (HeapTuple *)
1782 palloc(rtsize * sizeof(HeapTuple));
1783 memset(epqstate->es_evTuple, 0, rtsize * sizeof(HeapTuple));
1787 /* later stack entries share the same storage */
1788 epqstate->es_evTuple = epq->estate.es_evTuple;
1793 /* recycle previously used EState */
1794 epqstate = &(newepq->estate);
1796 /* push current PQ to the stack */
1797 epqstate->es_evalPlanQual = (Pointer) epq;
1799 estate->es_evalPlanQual = (Pointer) epq;
1804 Assert(epq->rti == rti);
1805 epqstate = &(epq->estate);
1808 * Ok - we're requested for the same RTE. Unfortunately we still have
1809 * to end and restart execution of the plan, because ExecReScan
1810 * wouldn't ensure that upper plan nodes would reset themselves. We
1811 * could make that work if insertion of the target tuple were
1812 * integrated with the Param mechanism somehow, so that the upper plan
1813 * nodes know that their children's outputs have changed.
1817 /* stop execution */
1818 ExecEndNode(epq->plan, NULL);
1819 ExecDropTupleTable(epqstate->es_tupleTable, true);
1820 epqstate->es_tupleTable = NULL;
1824 * free old RTE' tuple, if any, and store target tuple where
1825 * relation's scan node will see it
1827 if (epqstate->es_evTuple[rti - 1] != NULL)
1828 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1829 epqstate->es_evTuple[rti - 1] = copyTuple;
1832 * Initialize for new recheck query; be careful to copy down state
1833 * that might have changed in top EState.
1835 epqstate->es_result_relation_info = estate->es_result_relation_info;
1836 epqstate->es_junkFilter = estate->es_junkFilter;
1837 if (estate->es_origPlan->nParamExec > 0)
1838 memset(epqstate->es_param_exec_vals, 0,
1839 estate->es_origPlan->nParamExec * sizeof(ParamExecData));
1840 memset(epqstate->es_evTupleNull, false, rtsize * sizeof(bool));
1841 epqstate->es_useEvalPlan = false;
1842 Assert(epqstate->es_tupleTable == NULL);
1843 epqstate->es_tupleTable =
1844 ExecCreateTupleTable(estate->es_tupleTable->size);
1846 ExecInitNode(epq->plan, epqstate, NULL);
1848 return EvalPlanQualNext(estate);
1851 static TupleTableSlot *
1852 EvalPlanQualNext(EState *estate)
1854 evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1855 EState *epqstate = &(epq->estate);
1856 evalPlanQual *oldepq;
1857 TupleTableSlot *slot;
1859 Assert(epq->rti != 0);
1862 slot = ExecProcNode(epq->plan, NULL);
1865 * No more tuples for this PQ. Continue previous one.
1867 if (TupIsNull(slot))
1869 /* stop execution */
1870 ExecEndNode(epq->plan, NULL);
1871 ExecDropTupleTable(epqstate->es_tupleTable, true);
1872 epqstate->es_tupleTable = NULL;
1873 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1874 epqstate->es_evTuple[epq->rti - 1] = NULL;
1875 /* pop old PQ from the stack */
1876 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1877 if (oldepq == (evalPlanQual *) NULL)
1879 epq->rti = 0; /* this is the first (oldest) */
1880 estate->es_useEvalPlan = false; /* PQ - mark as free and */
1881 return (NULL); /* continue Query execution */
1883 Assert(oldepq->rti != 0);
1884 /* push current PQ to freePQ stack */
1887 epqstate = &(epq->estate);
1888 estate->es_evalPlanQual = (Pointer) epq;
1896 EndEvalPlanQual(EState *estate)
1898 evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1899 EState *epqstate = &(epq->estate);
1900 evalPlanQual *oldepq;
1902 if (epq->rti == 0) /* plans already shutdowned */
1904 Assert(epq->estate.es_evalPlanQual == NULL);
1910 /* stop execution */
1911 ExecEndNode(epq->plan, NULL);
1912 ExecDropTupleTable(epqstate->es_tupleTable, true);
1913 epqstate->es_tupleTable = NULL;
1914 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1916 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1917 epqstate->es_evTuple[epq->rti - 1] = NULL;
1919 /* pop old PQ from the stack */
1920 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1921 if (oldepq == (evalPlanQual *) NULL)
1923 epq->rti = 0; /* this is the first (oldest) */
1924 estate->es_useEvalPlan = false; /* PQ - mark as free */
1927 Assert(oldepq->rti != 0);
1928 /* push current PQ to freePQ stack */
1931 epqstate = &(epq->estate);
1932 estate->es_evalPlanQual = (Pointer) epq;