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11 * The old ExecutorMain() has been replaced by ExecutorStart(),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 'feature' and 'count' arguments that specify whether
23 * the plan is to be executed forwards, backwards, and for how many tuples.
25 * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
26 * Portions Copyright (c) 1994, Regents of the University of California
30 * $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.133 2000/12/05 22:03:57 tgl Exp $
32 *-------------------------------------------------------------------------
36 #include "access/heapam.h"
37 #include "catalog/heap.h"
38 #include "commands/command.h"
39 #include "commands/trigger.h"
40 #include "executor/execdebug.h"
41 #include "executor/execdefs.h"
42 #include "miscadmin.h"
43 #include "optimizer/var.h"
44 #include "parser/parsetree.h"
45 #include "utils/acl.h"
48 /* decls for local routines only used within this module */
49 static TupleDesc InitPlan(CmdType operation,
53 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
54 Index resultRelationIndex,
57 static void EndPlan(Plan *plan, EState *estate);
58 static TupleTableSlot *ExecutePlan(EState *estate, Plan *plan,
61 ScanDirection direction,
62 DestReceiver *destfunc);
63 static void ExecRetrieve(TupleTableSlot *slot,
64 DestReceiver *destfunc,
66 static void ExecAppend(TupleTableSlot *slot, ItemPointer tupleid,
68 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
70 static void ExecReplace(TupleTableSlot *slot, ItemPointer tupleid,
72 static TupleTableSlot *EvalPlanQualNext(EState *estate);
73 static void EndEvalPlanQual(EState *estate);
74 static void ExecCheckQueryPerms(CmdType operation, Query *parseTree,
76 static void ExecCheckPlanPerms(Plan *plan, List *rangeTable,
78 static void ExecCheckRTPerms(List *rangeTable, CmdType operation);
79 static void ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation);
81 /* end of local decls */
84 /* ----------------------------------------------------------------
87 * This routine must be called at the beginning of any execution of any
90 * returns a TupleDesc which describes the attributes of the tuples to
91 * be returned by the query.
93 * NB: the CurrentMemoryContext when this is called must be the context
94 * to be used as the per-query context for the query plan. ExecutorRun()
95 * and ExecutorEnd() must be called in this same memory context.
96 * ----------------------------------------------------------------
99 ExecutorStart(QueryDesc *queryDesc, EState *estate)
104 Assert(queryDesc != NULL);
106 if (queryDesc->plantree->nParamExec > 0)
108 estate->es_param_exec_vals = (ParamExecData *)
109 palloc(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
110 MemSet(estate->es_param_exec_vals, 0,
111 queryDesc->plantree->nParamExec * sizeof(ParamExecData));
115 * Make our own private copy of the current queries snapshot data
117 if (QuerySnapshot == NULL)
118 estate->es_snapshot = NULL;
121 estate->es_snapshot = (Snapshot) palloc(sizeof(SnapshotData));
122 memcpy(estate->es_snapshot, QuerySnapshot, sizeof(SnapshotData));
123 if (estate->es_snapshot->xcnt > 0)
125 estate->es_snapshot->xip = (TransactionId *)
126 palloc(estate->es_snapshot->xcnt * sizeof(TransactionId));
127 memcpy(estate->es_snapshot->xip, QuerySnapshot->xip,
128 estate->es_snapshot->xcnt * sizeof(TransactionId));
133 * Initialize the plan
135 result = InitPlan(queryDesc->operation,
136 queryDesc->parsetree,
143 /* ----------------------------------------------------------------
146 * This is the main routine of the executor module. It accepts
147 * the query descriptor from the traffic cop and executes the
150 * ExecutorStart must have been called already.
152 * the different features supported are:
153 * EXEC_RUN: retrieve all tuples in the forward direction
154 * EXEC_FOR: retrieve 'count' number of tuples in the forward dir
155 * EXEC_BACK: retrieve 'count' number of tuples in the backward dir
156 * EXEC_RETONE: return one tuple but don't 'retrieve' it
157 * used in postquel function processing
159 * Note: count = 0 is interpreted as "no limit".
161 * ----------------------------------------------------------------
164 ExecutorRun(QueryDesc *queryDesc, EState *estate, int feature, long count)
168 TupleTableSlot *result;
170 DestReceiver *destfunc;
175 Assert(queryDesc != NULL);
178 * extract information from the query descriptor and the query
181 operation = queryDesc->operation;
182 plan = queryDesc->plantree;
183 dest = queryDesc->dest;
184 destfunc = DestToFunction(dest);
185 estate->es_processed = 0;
186 estate->es_lastoid = InvalidOid;
189 * FIXME: the dest setup function ought to be handed the tuple desc
190 * for the tuples to be output, but I'm not quite sure how to get that
191 * info at this point. For now, passing NULL is OK because no
192 * existing dest setup function actually uses the pointer.
194 (*destfunc->setup) (destfunc, (TupleDesc) NULL);
199 result = ExecutePlan(estate,
203 ForwardScanDirection,
208 result = ExecutePlan(estate,
212 ForwardScanDirection,
217 * retrieve next n "backward" tuples
220 result = ExecutePlan(estate,
224 BackwardScanDirection,
229 * return one tuple but don't "retrieve" it. (this is used by
230 * the rule manager..) -cim 9/14/89
233 result = ExecutePlan(estate,
237 ForwardScanDirection,
242 elog(DEBUG, "ExecutorRun: Unknown feature %d", feature);
247 (*destfunc->cleanup) (destfunc);
252 /* ----------------------------------------------------------------
255 * This routine must be called at the end of any execution of any
258 * returns (AttrInfo*) which describes the attributes of the tuples to
259 * be returned by the query.
261 * ----------------------------------------------------------------
264 ExecutorEnd(QueryDesc *queryDesc, EState *estate)
267 Assert(queryDesc != NULL);
269 EndPlan(queryDesc->plantree, estate);
271 /* XXX - clean up some more from ExecutorStart() - er1p */
272 if (NULL == estate->es_snapshot)
274 /* nothing to free */
278 if (estate->es_snapshot->xcnt > 0)
279 pfree(estate->es_snapshot->xip);
280 pfree(estate->es_snapshot);
283 if (NULL == estate->es_param_exec_vals)
285 /* nothing to free */
289 pfree(estate->es_param_exec_vals);
290 estate->es_param_exec_vals = NULL;
296 * ExecCheckQueryPerms
297 * Check access permissions for all relations referenced in a query.
300 ExecCheckQueryPerms(CmdType operation, Query *parseTree, Plan *plan)
303 * Check RTEs in the query's primary rangetable.
305 ExecCheckRTPerms(parseTree->rtable, operation);
308 * Search for subplans and APPEND nodes to check their rangetables.
310 ExecCheckPlanPerms(plan, parseTree->rtable, operation);
315 * Recursively scan the plan tree to check access permissions in
319 ExecCheckPlanPerms(Plan *plan, List *rangeTable, CmdType operation)
326 /* Check subplans, which we assume are plain SELECT queries */
328 foreach(subp, plan->initPlan)
330 SubPlan *subplan = (SubPlan *) lfirst(subp);
332 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
333 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
335 foreach(subp, plan->subPlan)
337 SubPlan *subplan = (SubPlan *) lfirst(subp);
339 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
340 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
343 /* Check lower plan nodes */
345 ExecCheckPlanPerms(plan->lefttree, rangeTable, operation);
346 ExecCheckPlanPerms(plan->righttree, rangeTable, operation);
348 /* Do node-type-specific checks */
350 switch (nodeTag(plan))
354 SubqueryScan *scan = (SubqueryScan *) plan;
357 /* Recursively check the subquery */
358 rte = rt_fetch(scan->scan.scanrelid, rangeTable);
359 Assert(rte->subquery != NULL);
360 ExecCheckQueryPerms(operation, rte->subquery, scan->subplan);
365 Append *app = (Append *) plan;
368 foreach(appendplans, app->appendplans)
370 ExecCheckPlanPerms((Plan *) lfirst(appendplans),
384 * Check access permissions for all relations listed in a range table.
387 ExecCheckRTPerms(List *rangeTable, CmdType operation)
391 foreach(lp, rangeTable)
393 RangeTblEntry *rte = lfirst(lp);
395 ExecCheckRTEPerms(rte, operation);
401 * Check access permissions for a single RTE.
404 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
408 int32 aclcheck_result;
411 * If it's a subquery RTE, ignore it --- it will be checked when
412 * ExecCheckPlanPerms finds the SubqueryScan node for it.
417 relName = rte->relname;
420 * userid to check as: current user unless we have a setuid indication.
422 * Note: GetUserId() is presently fast enough that there's no harm
423 * in calling it separately for each RTE. If that stops being true,
424 * we could call it once in ExecCheckQueryPerms and pass the userid
425 * down from there. But for now, no need for the extra clutter.
427 userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
429 #define CHECK(MODE) pg_aclcheck(relName, userid, MODE)
431 if (rte->checkForRead)
433 aclcheck_result = CHECK(ACL_RD);
434 if (aclcheck_result != ACLCHECK_OK)
435 elog(ERROR, "%s: %s",
436 relName, aclcheck_error_strings[aclcheck_result]);
439 if (rte->checkForWrite)
442 * Note: write access in a SELECT context means SELECT FOR UPDATE.
443 * Right now we don't distinguish that from true update as far as
444 * permissions checks are concerned.
449 /* Accept either APPEND or WRITE access for this */
450 aclcheck_result = CHECK(ACL_AP);
451 if (aclcheck_result != ACLCHECK_OK)
452 aclcheck_result = CHECK(ACL_WR);
457 aclcheck_result = CHECK(ACL_WR);
460 elog(ERROR, "ExecCheckRTEPerms: bogus operation %d",
462 aclcheck_result = ACLCHECK_OK; /* keep compiler quiet */
465 if (aclcheck_result != ACLCHECK_OK)
466 elog(ERROR, "%s: %s",
467 relName, aclcheck_error_strings[aclcheck_result]);
472 /* ===============================================================
473 * ===============================================================
474 static routines follow
475 * ===============================================================
476 * ===============================================================
479 typedef struct execRowMark
486 typedef struct evalPlanQual
491 struct evalPlanQual *free;
494 /* ----------------------------------------------------------------
497 * Initializes the query plan: open files, allocate storage
498 * and start up the rule manager
499 * ----------------------------------------------------------------
502 InitPlan(CmdType operation, Query *parseTree, Plan *plan, EState *estate)
505 Relation intoRelationDesc;
509 * Do permissions checks.
511 ExecCheckQueryPerms(operation, parseTree, plan);
514 * get information from query descriptor
516 rangeTable = parseTree->rtable;
519 * initialize the node's execution state
521 estate->es_range_table = rangeTable;
524 * if there is a result relation, initialize result relation stuff
526 if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
528 List *resultRelations = parseTree->resultRelations;
529 int numResultRelations;
530 ResultRelInfo *resultRelInfos;
532 if (resultRelations != NIL)
535 * Multiple result relations (due to inheritance)
536 * parseTree->resultRelations identifies them all
538 ResultRelInfo *resultRelInfo;
540 numResultRelations = length(resultRelations);
541 resultRelInfos = (ResultRelInfo *)
542 palloc(numResultRelations * sizeof(ResultRelInfo));
543 resultRelInfo = resultRelInfos;
544 while (resultRelations != NIL)
546 initResultRelInfo(resultRelInfo,
547 lfirsti(resultRelations),
551 resultRelations = lnext(resultRelations);
557 * Single result relation identified by parseTree->resultRelation
559 numResultRelations = 1;
560 resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
561 initResultRelInfo(resultRelInfos,
562 parseTree->resultRelation,
567 estate->es_result_relations = resultRelInfos;
568 estate->es_num_result_relations = numResultRelations;
569 /* Initialize to first or only result rel */
570 estate->es_result_relation_info = resultRelInfos;
575 * if no result relation, then set state appropriately
577 estate->es_result_relations = NULL;
578 estate->es_num_result_relations = 0;
579 estate->es_result_relation_info = NULL;
583 * Have to lock relations selected for update
585 estate->es_rowMark = NIL;
586 if (parseTree->rowMarks != NIL)
590 foreach(l, parseTree->rowMarks)
592 Index rti = lfirsti(l);
593 Oid relid = getrelid(rti, rangeTable);
597 relation = heap_open(relid, RowShareLock);
598 erm = (execRowMark *) palloc(sizeof(execRowMark));
599 erm->relation = relation;
601 sprintf(erm->resname, "ctid%u", rti);
602 estate->es_rowMark = lappend(estate->es_rowMark, erm);
607 * initialize the executor "tuple" table.
610 int nSlots = ExecCountSlotsNode(plan);
611 TupleTable tupleTable = ExecCreateTupleTable(nSlots + 10); /* why add ten? - jolly */
613 estate->es_tupleTable = tupleTable;
617 * initialize the private state information for all the nodes in the
618 * query tree. This opens files, allocates storage and leaves us
619 * ready to start processing tuples.
621 ExecInitNode(plan, estate, NULL);
624 * Get the tuple descriptor describing the type of tuples to return.
625 * (this is especially important if we are creating a relation with
628 tupType = ExecGetTupType(plan); /* tuple descriptor */
631 * Initialize the junk filter if needed. SELECT and INSERT queries need
632 * a filter if there are any junk attrs in the tlist. UPDATE and
633 * DELETE always need one, since there's always a junk 'ctid' attribute
634 * present --- no need to look first.
637 bool junk_filter_needed = false;
644 foreach(tlist, plan->targetlist)
646 TargetEntry *tle = (TargetEntry *) lfirst(tlist);
648 if (tle->resdom->resjunk)
650 junk_filter_needed = true;
657 junk_filter_needed = true;
663 if (junk_filter_needed)
666 * If there are multiple result relations, each one needs
667 * its own junk filter. Note this is only possible for
668 * UPDATE/DELETE, so we can't be fooled by some needing
669 * a filter and some not.
671 if (parseTree->resultRelations != NIL)
674 ResultRelInfo *resultRelInfo;
676 /* Top plan had better be an Append here. */
677 Assert(IsA(plan, Append));
678 Assert(((Append *) plan)->isTarget);
679 subplans = ((Append *) plan)->appendplans;
680 Assert(length(subplans) == estate->es_num_result_relations);
681 resultRelInfo = estate->es_result_relations;
682 while (subplans != NIL)
684 Plan *subplan = (Plan *) lfirst(subplans);
687 j = ExecInitJunkFilter(subplan->targetlist,
688 ExecGetTupType(subplan));
689 resultRelInfo->ri_junkFilter = j;
691 subplans = lnext(subplans);
694 * Set active junkfilter too; at this point ExecInitAppend
695 * has already selected an active result relation...
697 estate->es_junkFilter =
698 estate->es_result_relation_info->ri_junkFilter;
702 /* Normal case with just one JunkFilter */
703 JunkFilter *j = ExecInitJunkFilter(plan->targetlist,
706 estate->es_junkFilter = j;
707 if (estate->es_result_relation_info)
708 estate->es_result_relation_info->ri_junkFilter = j;
710 /* For SELECT, want to return the cleaned tuple type */
711 if (operation == CMD_SELECT)
712 tupType = j->jf_cleanTupType;
716 estate->es_junkFilter = NULL;
720 * initialize the "into" relation
722 intoRelationDesc = (Relation) NULL;
724 if (operation == CMD_SELECT)
730 if (!parseTree->isPortal)
734 * a select into table
736 if (parseTree->into != NULL)
740 * create the "into" relation
742 intoName = parseTree->into;
745 * have to copy tupType to get rid of constraints
747 tupdesc = CreateTupleDescCopy(tupType);
750 heap_create_with_catalog(intoName,
754 allowSystemTableMods);
756 FreeTupleDesc(tupdesc);
759 * Advance command counter so that the newly-created
760 * relation's catalog tuples will be visible to heap_open.
762 CommandCounterIncrement();
765 * Eventually create a TOAST table for the into relation
767 AlterTableCreateToastTable(intoName, true);
769 intoRelationDesc = heap_open(intoRelationId,
770 AccessExclusiveLock);
775 estate->es_into_relation_descriptor = intoRelationDesc;
777 estate->es_origPlan = plan;
778 estate->es_evalPlanQual = NULL;
779 estate->es_evTuple = NULL;
780 estate->es_useEvalPlan = false;
786 * Initialize ResultRelInfo data for one result relation
789 initResultRelInfo(ResultRelInfo *resultRelInfo,
790 Index resultRelationIndex,
794 Oid resultRelationOid;
795 Relation resultRelationDesc;
797 resultRelationOid = getrelid(resultRelationIndex, rangeTable);
798 resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
800 switch (resultRelationDesc->rd_rel->relkind)
802 case RELKIND_SEQUENCE:
803 elog(ERROR, "You can't change sequence relation %s",
804 RelationGetRelationName(resultRelationDesc));
806 case RELKIND_TOASTVALUE:
807 elog(ERROR, "You can't change toast relation %s",
808 RelationGetRelationName(resultRelationDesc));
811 elog(ERROR, "You can't change view relation %s",
812 RelationGetRelationName(resultRelationDesc));
816 MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
817 resultRelInfo->type = T_ResultRelInfo;
818 resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
819 resultRelInfo->ri_RelationDesc = resultRelationDesc;
820 resultRelInfo->ri_NumIndices = 0;
821 resultRelInfo->ri_IndexRelationDescs = NULL;
822 resultRelInfo->ri_IndexRelationInfo = NULL;
823 resultRelInfo->ri_ConstraintExprs = NULL;
824 resultRelInfo->ri_junkFilter = NULL;
827 * If there are indices on the result relation, open them and save
828 * descriptors in the result relation info, so that we can add new
829 * index entries for the tuples we add/update. We need not do
830 * this for a DELETE, however, since deletion doesn't affect
833 if (resultRelationDesc->rd_rel->relhasindex &&
834 operation != CMD_DELETE)
835 ExecOpenIndices(resultRelInfo);
838 /* ----------------------------------------------------------------
841 * Cleans up the query plan -- closes files and free up storages
842 * ----------------------------------------------------------------
845 EndPlan(Plan *plan, EState *estate)
847 ResultRelInfo *resultRelInfo;
852 * shut down any PlanQual processing we were doing
854 if (estate->es_evalPlanQual != NULL)
855 EndEvalPlanQual(estate);
858 * shut down the node-type-specific query processing
860 ExecEndNode(plan, plan);
863 * destroy the executor "tuple" table.
865 ExecDropTupleTable(estate->es_tupleTable, true);
866 estate->es_tupleTable = NULL;
869 * close the result relation(s) if any, but hold locks
872 resultRelInfo = estate->es_result_relations;
873 for (i = estate->es_num_result_relations; i > 0; i--)
875 /* Close indices and then the relation itself */
876 ExecCloseIndices(resultRelInfo);
877 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
882 * close the "into" relation if necessary, again keeping lock
884 if (estate->es_into_relation_descriptor != NULL)
885 heap_close(estate->es_into_relation_descriptor, NoLock);
888 * close any relations selected FOR UPDATE, again keeping locks
890 foreach(l, estate->es_rowMark)
892 execRowMark *erm = lfirst(l);
894 heap_close(erm->relation, NoLock);
898 /* ----------------------------------------------------------------
901 * processes the query plan to retrieve 'numberTuples' tuples in the
902 * direction specified.
903 * Retrieves all tuples if tupleCount is 0
905 * result is either a slot containing the last tuple in the case
906 * of a RETRIEVE or NULL otherwise.
908 * Note: the ctid attribute is a 'junk' attribute that is removed before the
910 * ----------------------------------------------------------------
912 static TupleTableSlot *
913 ExecutePlan(EState *estate,
917 ScanDirection direction,
918 DestReceiver *destfunc)
920 JunkFilter *junkfilter;
921 TupleTableSlot *slot;
922 ItemPointer tupleid = NULL;
923 ItemPointerData tuple_ctid;
924 long current_tuple_count;
925 TupleTableSlot *result;
928 * initialize local variables
931 current_tuple_count = 0;
937 estate->es_direction = direction;
940 * Loop until we've processed the proper number of tuples from the
948 * Execute the plan and obtain a tuple
950 /* at the top level, the parent of a plan (2nd arg) is itself */
952 if (estate->es_useEvalPlan)
954 slot = EvalPlanQualNext(estate);
956 slot = ExecProcNode(plan, plan);
959 slot = ExecProcNode(plan, plan);
962 * if the tuple is null, then we assume there is nothing more to
963 * process so we just return null...
972 * if we have a junk filter, then project a new tuple with the
975 * Store this new "clean" tuple in the place of the original tuple.
977 * Also, extract all the junk information we need.
979 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
986 * extract the 'ctid' junk attribute.
988 if (operation == CMD_UPDATE || operation == CMD_DELETE)
990 if (!ExecGetJunkAttribute(junkfilter,
995 elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
997 /* shouldn't ever get a null result... */
999 elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
1001 tupleid = (ItemPointer) DatumGetPointer(datum);
1002 tuple_ctid = *tupleid; /* make sure we don't free the
1004 tupleid = &tuple_ctid;
1006 else if (estate->es_rowMark != NIL)
1011 foreach(l, estate->es_rowMark)
1013 execRowMark *erm = lfirst(l);
1015 HeapTupleData tuple;
1016 TupleTableSlot *newSlot;
1019 if (!ExecGetJunkAttribute(junkfilter,
1024 elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
1028 * Unlike the UPDATE/DELETE case, a null result is
1029 * possible here, when the referenced table is on the
1030 * nullable side of an outer join. Ignore nulls.
1035 tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1036 test = heap_mark4update(erm->relation, &tuple, &buffer);
1037 ReleaseBuffer(buffer);
1040 case HeapTupleSelfUpdated:
1041 case HeapTupleMayBeUpdated:
1044 case HeapTupleUpdated:
1045 if (XactIsoLevel == XACT_SERIALIZABLE)
1046 elog(ERROR, "Can't serialize access due to concurrent update");
1047 if (!(ItemPointerEquals(&(tuple.t_self),
1048 (ItemPointer) DatumGetPointer(datum))))
1050 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1051 if (!(TupIsNull(newSlot)))
1054 estate->es_useEvalPlan = true;
1060 * if tuple was deleted or PlanQual failed for
1061 * updated tuple - we have not return this
1067 elog(ERROR, "Unknown status %u from heap_mark4update", test);
1074 * Finally create a new "clean" tuple with all junk attributes
1077 newTuple = ExecRemoveJunk(junkfilter, slot);
1079 slot = ExecStoreTuple(newTuple, /* tuple to store */
1080 slot, /* destination slot */
1081 InvalidBuffer, /* this tuple has no
1083 true); /* tuple should be pfreed */
1084 } /* if (junkfilter... */
1087 * now that we have a tuple, do the appropriate thing with it..
1088 * either return it to the user, add it to a relation someplace,
1089 * delete it from a relation, or modify some of its attributes.
1095 ExecRetrieve(slot, /* slot containing tuple */
1096 destfunc, /* destination's tuple-receiver
1103 ExecAppend(slot, tupleid, estate);
1108 ExecDelete(slot, tupleid, estate);
1113 ExecReplace(slot, tupleid, estate);
1118 elog(DEBUG, "ExecutePlan: unknown operation in queryDesc");
1124 * check our tuple count.. if we've processed the proper number
1125 * then quit, else loop again and process more tuples..
1127 current_tuple_count++;
1128 if (numberTuples == current_tuple_count)
1133 * here, result is either a slot containing a tuple in the case of a
1134 * RETRIEVE or NULL otherwise.
1139 /* ----------------------------------------------------------------
1142 * RETRIEVEs are easy.. we just pass the tuple to the appropriate
1143 * print function. The only complexity is when we do a
1144 * "retrieve into", in which case we insert the tuple into
1145 * the appropriate relation (note: this is a newly created relation
1146 * so we don't need to worry about indices or locks.)
1147 * ----------------------------------------------------------------
1150 ExecRetrieve(TupleTableSlot *slot,
1151 DestReceiver *destfunc,
1158 * get the heap tuple out of the tuple table slot
1161 attrtype = slot->ttc_tupleDescriptor;
1164 * insert the tuple into the "into relation"
1166 if (estate->es_into_relation_descriptor != NULL)
1168 heap_insert(estate->es_into_relation_descriptor, tuple);
1173 * send the tuple to the front end (or the screen)
1175 (*destfunc->receiveTuple) (tuple, attrtype, destfunc);
1177 (estate->es_processed)++;
1180 /* ----------------------------------------------------------------
1183 * APPENDs are trickier.. we have to insert the tuple into
1184 * the base relation and insert appropriate tuples into the
1186 * ----------------------------------------------------------------
1190 ExecAppend(TupleTableSlot *slot,
1191 ItemPointer tupleid,
1195 ResultRelInfo *resultRelInfo;
1196 Relation resultRelationDesc;
1201 * get the heap tuple out of the tuple table slot
1206 * get information on the (current) result relation
1208 resultRelInfo = estate->es_result_relation_info;
1209 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1211 /* BEFORE ROW INSERT Triggers */
1212 if (resultRelationDesc->trigdesc &&
1213 resultRelationDesc->trigdesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1217 newtuple = ExecBRInsertTriggers(resultRelationDesc, tuple);
1219 if (newtuple == NULL) /* "do nothing" */
1222 if (newtuple != tuple) /* modified by Trigger(s) */
1224 Assert(slot->ttc_shouldFree);
1225 heap_freetuple(tuple);
1226 slot->val = tuple = newtuple;
1231 * Check the constraints of the tuple
1233 if (resultRelationDesc->rd_att->constr)
1234 ExecConstraints("ExecAppend", resultRelInfo, slot, estate);
1239 newId = heap_insert(resultRelationDesc, tuple);
1242 (estate->es_processed)++;
1243 estate->es_lastoid = newId;
1248 * Note: heap_insert adds a new tuple to a relation. As a side effect,
1249 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1252 numIndices = resultRelInfo->ri_NumIndices;
1254 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1256 /* AFTER ROW INSERT Triggers */
1257 if (resultRelationDesc->trigdesc)
1258 ExecARInsertTriggers(resultRelationDesc, tuple);
1261 /* ----------------------------------------------------------------
1264 * DELETE is like append, we delete the tuple and its
1266 * ----------------------------------------------------------------
1269 ExecDelete(TupleTableSlot *slot,
1270 ItemPointer tupleid,
1273 ResultRelInfo *resultRelInfo;
1274 Relation resultRelationDesc;
1275 ItemPointerData ctid;
1279 * get information on the (current) result relation
1281 resultRelInfo = estate->es_result_relation_info;
1282 resultRelationDesc = resultRelInfo->ri_RelationDesc;
1284 /* BEFORE ROW DELETE Triggers */
1285 if (resultRelationDesc->trigdesc &&
1286 resultRelationDesc->trigdesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1290 dodelete = ExecBRDeleteTriggers(estate, tupleid);
1292 if (!dodelete) /* "do nothing" */
1300 result = heap_delete(resultRelationDesc, tupleid, &ctid);
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))
1326 elog(ERROR, "Unknown status %u from heap_delete", result);
1331 (estate->es_processed)++;
1334 * Note: Normally one would think that we have to delete index tuples
1335 * associated with the heap tuple now..
1337 * ... but in POSTGRES, we have no need to do this because the vacuum
1338 * daemon automatically opens an index scan and deletes index tuples
1339 * when it finds deleted heap tuples. -cim 9/27/89
1342 /* AFTER ROW DELETE Triggers */
1343 if (resultRelationDesc->trigdesc)
1344 ExecARDeleteTriggers(estate, tupleid);
1348 /* ----------------------------------------------------------------
1351 * note: we can't run replace queries with transactions
1352 * off because replaces are actually appends and our
1353 * scan will mistakenly loop forever, replacing the tuple
1354 * it just appended.. 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 ExecReplace(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(NOTICE, "ExecReplace: replace 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 (resultRelationDesc->trigdesc &&
1393 resultRelationDesc->trigdesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1397 newtuple = ExecBRUpdateTriggers(estate, tupleid, tuple);
1399 if (newtuple == NULL) /* "do nothing" */
1402 if (newtuple != tuple) /* modified by Trigger(s) */
1404 Assert(slot->ttc_shouldFree);
1405 heap_freetuple(tuple);
1406 slot->val = tuple = newtuple;
1411 * Check the constraints of the tuple
1413 if (resultRelationDesc->rd_att->constr)
1414 ExecConstraints("ExecReplace", resultRelInfo, slot, estate);
1417 * replace the heap tuple
1420 result = heap_update(resultRelationDesc, tupleid, tuple, &ctid);
1423 case HeapTupleSelfUpdated:
1426 case HeapTupleMayBeUpdated:
1429 case HeapTupleUpdated:
1430 if (XactIsoLevel == XACT_SERIALIZABLE)
1431 elog(ERROR, "Can't serialize access due to concurrent update");
1432 else if (!(ItemPointerEquals(tupleid, &ctid)))
1434 TupleTableSlot *epqslot = EvalPlanQual(estate,
1435 resultRelInfo->ri_RangeTableIndex, &ctid);
1437 if (!TupIsNull(epqslot))
1440 tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1441 slot = ExecStoreTuple(tuple, slot, InvalidBuffer, true);
1448 elog(ERROR, "Unknown status %u from heap_update", result);
1453 (estate->es_processed)++;
1456 * Note: instead of having to update the old index tuples associated
1457 * with the heap tuple, all we do is form and insert new index
1458 * tuples. This is because replaces are actually deletes and inserts
1459 * and index tuple deletion is done automagically by the vacuum
1460 * daemon. All we do is insert new index tuples. -cim 9/27/89
1466 * heap_update updates a tuple in the base relation by invalidating it
1467 * and then appending a new tuple to the relation. As a side effect,
1468 * the tupleid of the new tuple is placed in the new tuple's t_ctid
1469 * field. So we now insert index tuples using the new tupleid stored
1473 numIndices = resultRelInfo->ri_NumIndices;
1475 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, true);
1477 /* AFTER ROW UPDATE Triggers */
1478 if (resultRelationDesc->trigdesc)
1479 ExecARUpdateTriggers(estate, tupleid, tuple);
1483 ExecRelCheck(ResultRelInfo *resultRelInfo,
1484 TupleTableSlot *slot, EState *estate)
1486 Relation rel = resultRelInfo->ri_RelationDesc;
1487 int ncheck = rel->rd_att->constr->num_check;
1488 ConstrCheck *check = rel->rd_att->constr->check;
1489 ExprContext *econtext;
1490 MemoryContext oldContext;
1495 * If first time through for this result relation, build expression
1496 * nodetrees for rel's constraint expressions. Keep them in the
1497 * per-query memory context so they'll survive throughout the query.
1499 if (resultRelInfo->ri_ConstraintExprs == NULL)
1501 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1502 resultRelInfo->ri_ConstraintExprs =
1503 (List **) palloc(ncheck * sizeof(List *));
1504 for (i = 0; i < ncheck; i++)
1506 qual = (List *) stringToNode(check[i].ccbin);
1507 resultRelInfo->ri_ConstraintExprs[i] = qual;
1509 MemoryContextSwitchTo(oldContext);
1513 * We will use the EState's per-tuple context for evaluating constraint
1514 * expressions. Create it if it's not already there; if it is, reset it
1515 * to free previously-used storage.
1517 econtext = estate->es_per_tuple_exprcontext;
1518 if (econtext == NULL)
1520 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1521 estate->es_per_tuple_exprcontext = econtext =
1522 MakeExprContext(NULL, estate->es_query_cxt);
1523 MemoryContextSwitchTo(oldContext);
1526 ResetExprContext(econtext);
1528 /* Arrange for econtext's scan tuple to be the tuple under test */
1529 econtext->ecxt_scantuple = slot;
1531 /* And evaluate the constraints */
1532 for (i = 0; i < ncheck; i++)
1534 qual = resultRelInfo->ri_ConstraintExprs[i];
1537 * NOTE: SQL92 specifies that a NULL result from a constraint
1538 * expression is not to be treated as a failure. Therefore, tell
1539 * ExecQual to return TRUE for NULL.
1541 if (!ExecQual(qual, econtext, true))
1542 return check[i].ccname;
1545 /* NULL result means no error */
1546 return (char *) NULL;
1550 ExecConstraints(char *caller, ResultRelInfo *resultRelInfo,
1551 TupleTableSlot *slot, EState *estate)
1553 Relation rel = resultRelInfo->ri_RelationDesc;
1554 HeapTuple tuple = slot->val;
1555 TupleConstr *constr = rel->rd_att->constr;
1559 if (constr->has_not_null)
1561 int natts = rel->rd_att->natts;
1564 for (attrChk = 1; attrChk <= natts; attrChk++)
1566 if (rel->rd_att->attrs[attrChk-1]->attnotnull &&
1567 heap_attisnull(tuple, attrChk))
1568 elog(ERROR, "%s: Fail to add null value in not null attribute %s",
1569 caller, NameStr(rel->rd_att->attrs[attrChk-1]->attname));
1573 if (constr->num_check > 0)
1577 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1578 elog(ERROR, "%s: rejected due to CHECK constraint %s",
1584 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1586 evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1587 evalPlanQual *oldepq;
1588 EState *epqstate = NULL;
1591 HeapTupleData tuple;
1592 bool endNode = true;
1596 if (epq != NULL && epq->rti == 0)
1598 Assert(!(estate->es_useEvalPlan) &&
1599 epq->estate.es_evalPlanQual == NULL);
1605 * If this is request for another RTE - Ra, - then we have to check
1606 * wasn't PlanQual requested for Ra already and if so then Ra' row was
1607 * updated again and we have to re-start old execution for Ra and
1608 * forget all what we done after Ra was suspended. Cool? -:))
1610 if (epq != NULL && epq->rti != rti &&
1611 epq->estate.es_evTuple[rti - 1] != NULL)
1615 /* pop previous PlanQual from the stack */
1616 epqstate = &(epq->estate);
1617 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1618 Assert(oldepq->rti != 0);
1619 /* stop execution */
1620 ExecEndNode(epq->plan, epq->plan);
1621 epqstate->es_tupleTable->next = 0;
1622 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1623 epqstate->es_evTuple[epq->rti - 1] = NULL;
1624 /* push current PQ to freePQ stack */
1627 } while (epq->rti != rti);
1628 estate->es_evalPlanQual = (Pointer) epq;
1632 * If we are requested for another RTE then we have to suspend
1633 * execution of current PlanQual and start execution for new one.
1635 if (epq == NULL || epq->rti != rti)
1637 /* try to reuse plan used previously */
1638 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1640 if (newepq == NULL) /* first call or freePQ stack is empty */
1642 newepq = (evalPlanQual *) palloc(sizeof(evalPlanQual));
1644 epqstate = &(newepq->estate);
1645 memset(epqstate, 0, sizeof(EState));
1646 epqstate->type = T_EState;
1647 epqstate->es_direction = ForwardScanDirection;
1648 epqstate->es_snapshot = estate->es_snapshot;
1649 epqstate->es_range_table = estate->es_range_table;
1650 epqstate->es_param_list_info = estate->es_param_list_info;
1651 if (estate->es_origPlan->nParamExec > 0)
1652 epqstate->es_param_exec_vals = (ParamExecData *)
1653 palloc(estate->es_origPlan->nParamExec *
1654 sizeof(ParamExecData));
1655 epqstate->es_tupleTable =
1656 ExecCreateTupleTable(estate->es_tupleTable->size);
1658 newepq->plan = copyObject(estate->es_origPlan);
1659 newepq->free = NULL;
1660 epqstate->es_evTupleNull = (bool *)
1661 palloc(length(estate->es_range_table) * sizeof(bool));
1662 if (epq == NULL) /* first call */
1664 epqstate->es_evTuple = (HeapTuple *)
1665 palloc(length(estate->es_range_table) * sizeof(HeapTuple));
1666 memset(epqstate->es_evTuple, 0,
1667 length(estate->es_range_table) * sizeof(HeapTuple));
1670 epqstate->es_evTuple = epq->estate.es_evTuple;
1673 epqstate = &(newepq->estate);
1674 /* push current PQ to the stack */
1675 epqstate->es_evalPlanQual = (Pointer) epq;
1677 estate->es_evalPlanQual = (Pointer) epq;
1682 epqstate = &(epq->estate);
1685 * Ok - we're requested for the same RTE (-:)). I'm not sure about
1686 * ability to use ExecReScan instead of ExecInitNode, so...
1690 ExecEndNode(epq->plan, epq->plan);
1691 epqstate->es_tupleTable->next = 0;
1694 /* free old RTE' tuple */
1695 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1697 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1698 epqstate->es_evTuple[epq->rti - 1] = NULL;
1701 /* ** fetch tid tuple ** */
1702 if (estate->es_result_relation_info != NULL &&
1703 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1704 relation = estate->es_result_relation_info->ri_RelationDesc;
1709 foreach(l, estate->es_rowMark)
1711 if (((execRowMark *) lfirst(l))->rti == rti)
1714 relation = ((execRowMark *) lfirst(l))->relation;
1716 tuple.t_self = *tid;
1719 heap_fetch(relation, SnapshotDirty, &tuple, &buffer);
1720 if (tuple.t_data != NULL)
1722 TransactionId xwait = SnapshotDirty->xmax;
1724 if (TransactionIdIsValid(SnapshotDirty->xmin))
1726 elog(NOTICE, "EvalPlanQual: t_xmin is uncommitted ?!");
1727 Assert(!TransactionIdIsValid(SnapshotDirty->xmin));
1728 elog(ERROR, "Aborting this transaction");
1732 * If tuple is being updated by other transaction then we have
1733 * to wait for its commit/abort.
1735 if (TransactionIdIsValid(xwait))
1737 ReleaseBuffer(buffer);
1738 XactLockTableWait(xwait);
1743 * Nice! We got tuple - now copy it.
1745 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1746 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1747 epqstate->es_evTuple[epq->rti - 1] = heap_copytuple(&tuple);
1748 ReleaseBuffer(buffer);
1753 * Ops! Invalid tuple. Have to check is it updated or deleted.
1754 * Note that it's possible to get invalid SnapshotDirty->tid if
1755 * tuple updated by this transaction. Have we to check this ?
1757 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1758 !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1760 tuple.t_self = SnapshotDirty->tid; /* updated ... */
1765 * Deleted or updated by this transaction. Do not (re-)start
1766 * execution of this PQ. Continue previous PQ.
1768 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1771 Assert(oldepq->rti != 0);
1772 /* push current PQ to freePQ stack */
1775 epqstate = &(epq->estate);
1776 estate->es_evalPlanQual = (Pointer) epq;
1780 epq->rti = 0; /* this is the first (oldest) */
1781 estate->es_useEvalPlan = false; /* PQ - mark as free and */
1782 return (NULL); /* continue Query execution */
1786 if (estate->es_origPlan->nParamExec > 0)
1787 memset(epqstate->es_param_exec_vals, 0,
1788 estate->es_origPlan->nParamExec * sizeof(ParamExecData));
1789 memset(epqstate->es_evTupleNull, false,
1790 length(estate->es_range_table) * sizeof(bool));
1791 Assert(epqstate->es_tupleTable->next == 0);
1792 ExecInitNode(epq->plan, epqstate, NULL);
1795 * For UPDATE/DELETE we have to return tid of actual row we're
1798 *tid = tuple.t_self;
1800 return EvalPlanQualNext(estate);
1803 static TupleTableSlot *
1804 EvalPlanQualNext(EState *estate)
1806 evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1807 EState *epqstate = &(epq->estate);
1808 evalPlanQual *oldepq;
1809 TupleTableSlot *slot;
1811 Assert(epq->rti != 0);
1814 slot = ExecProcNode(epq->plan, epq->plan);
1817 * No more tuples for this PQ. Continue previous one.
1819 if (TupIsNull(slot))
1821 ExecEndNode(epq->plan, epq->plan);
1822 epqstate->es_tupleTable->next = 0;
1823 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1824 epqstate->es_evTuple[epq->rti - 1] = NULL;
1825 /* pop old PQ from the stack */
1826 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1827 if (oldepq == (evalPlanQual *) NULL)
1829 epq->rti = 0; /* this is the first (oldest) */
1830 estate->es_useEvalPlan = false; /* PQ - mark as free and */
1831 return (NULL); /* continue Query execution */
1833 Assert(oldepq->rti != 0);
1834 /* push current PQ to freePQ stack */
1837 epqstate = &(epq->estate);
1838 estate->es_evalPlanQual = (Pointer) epq;
1846 EndEvalPlanQual(EState *estate)
1848 evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1849 EState *epqstate = &(epq->estate);
1850 evalPlanQual *oldepq;
1852 if (epq->rti == 0) /* plans already shutdowned */
1854 Assert(epq->estate.es_evalPlanQual == NULL);
1860 ExecEndNode(epq->plan, epq->plan);
1861 epqstate->es_tupleTable->next = 0;
1862 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1864 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1865 epqstate->es_evTuple[epq->rti - 1] = NULL;
1867 /* pop old PQ from the stack */
1868 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1869 if (oldepq == (evalPlanQual *) NULL)
1871 epq->rti = 0; /* this is the first (oldest) */
1872 estate->es_useEvalPlan = false; /* PQ - mark as free */
1875 Assert(oldepq->rti != 0);
1876 /* push current PQ to freePQ stack */
1879 epqstate = &(epq->estate);
1880 estate->es_evalPlanQual = (Pointer) epq;