/*------------------------------------------------------------------------- * * execMain.c * top level executor interface routines * * INTERFACE ROUTINES * ExecutorStart() * ExecutorRun() * ExecutorEnd() * * The old ExecutorMain() has been replaced by ExecutorStart(), * ExecutorRun() and ExecutorEnd() * * These three procedures are the external interfaces to the executor. * In each case, the query descriptor is required as an argument. * * ExecutorStart() must be called at the beginning of execution of any * query plan and ExecutorEnd() should always be called at the end of * execution of a plan. * * ExecutorRun accepts direction and count arguments that specify whether * the plan is to be executed forwards, backwards, and for how many tuples. * * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.332 2009/10/10 01:43:47 tgl Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/reloptions.h" #include "access/sysattr.h" #include "access/transam.h" #include "access/xact.h" #include "catalog/heap.h" #include "catalog/namespace.h" #include "catalog/toasting.h" #include "commands/tablespace.h" #include "commands/trigger.h" #include "executor/execdebug.h" #include "executor/instrument.h" #include "miscadmin.h" #include "optimizer/clauses.h" #include "parser/parse_clause.h" #include "parser/parsetree.h" #include "storage/bufmgr.h" #include "storage/lmgr.h" #include "utils/acl.h" #include "utils/lsyscache.h" #include "utils/memutils.h" #include "utils/snapmgr.h" #include "utils/tqual.h" /* Hooks for plugins to get control in ExecutorStart/Run/End() */ ExecutorStart_hook_type ExecutorStart_hook = NULL; ExecutorRun_hook_type ExecutorRun_hook = NULL; ExecutorEnd_hook_type ExecutorEnd_hook = NULL; typedef struct evalPlanQual { Index rti; EState *estate; PlanState *planstate; struct evalPlanQual *next; /* stack of active PlanQual plans */ struct evalPlanQual *free; /* list of free PlanQual plans */ } evalPlanQual; /* decls for local routines only used within this module */ static void InitPlan(QueryDesc *queryDesc, int eflags); static void ExecEndPlan(PlanState *planstate, EState *estate); static void ExecutePlan(EState *estate, PlanState *planstate, CmdType operation, bool sendTuples, long numberTuples, ScanDirection direction, DestReceiver *dest); static TupleTableSlot *EvalPlanQualNext(EState *estate); static void EndEvalPlanQual(EState *estate); static void ExecCheckRTPerms(List *rangeTable); static void ExecCheckRTEPerms(RangeTblEntry *rte); static void ExecCheckXactReadOnly(PlannedStmt *plannedstmt); static void EvalPlanQualStart(evalPlanQual *epq, EState *estate, Plan *planTree, evalPlanQual *priorepq); static void EvalPlanQualStop(evalPlanQual *epq); static void OpenIntoRel(QueryDesc *queryDesc); static void CloseIntoRel(QueryDesc *queryDesc); static void intorel_startup(DestReceiver *self, int operation, TupleDesc typeinfo); static void intorel_receive(TupleTableSlot *slot, DestReceiver *self); static void intorel_shutdown(DestReceiver *self); static void intorel_destroy(DestReceiver *self); /* end of local decls */ /* ---------------------------------------------------------------- * ExecutorStart * * This routine must be called at the beginning of any execution of any * query plan * * Takes a QueryDesc previously created by CreateQueryDesc (it's not real * clear why we bother to separate the two functions, but...). The tupDesc * field of the QueryDesc is filled in to describe the tuples that will be * returned, and the internal fields (estate and planstate) are set up. * * eflags contains flag bits as described in executor.h. * * NB: the CurrentMemoryContext when this is called will become the parent * of the per-query context used for this Executor invocation. * * We provide a function hook variable that lets loadable plugins * get control when ExecutorStart is called. Such a plugin would * normally call standard_ExecutorStart(). * * ---------------------------------------------------------------- */ void ExecutorStart(QueryDesc *queryDesc, int eflags) { if (ExecutorStart_hook) (*ExecutorStart_hook) (queryDesc, eflags); else standard_ExecutorStart(queryDesc, eflags); } void standard_ExecutorStart(QueryDesc *queryDesc, int eflags) { EState *estate; MemoryContext oldcontext; /* sanity checks: queryDesc must not be started already */ Assert(queryDesc != NULL); Assert(queryDesc->estate == NULL); /* * If the transaction is read-only, we need to check if any writes are * planned to non-temporary tables. EXPLAIN is considered read-only. */ if (XactReadOnly && !(eflags & EXEC_FLAG_EXPLAIN_ONLY)) ExecCheckXactReadOnly(queryDesc->plannedstmt); /* * Build EState, switch into per-query memory context for startup. */ estate = CreateExecutorState(); queryDesc->estate = estate; oldcontext = MemoryContextSwitchTo(estate->es_query_cxt); /* * Fill in parameters, if any, from queryDesc */ estate->es_param_list_info = queryDesc->params; if (queryDesc->plannedstmt->nParamExec > 0) estate->es_param_exec_vals = (ParamExecData *) palloc0(queryDesc->plannedstmt->nParamExec * sizeof(ParamExecData)); /* * If non-read-only query, set the command ID to mark output tuples with */ switch (queryDesc->operation) { case CMD_SELECT: /* SELECT INTO and SELECT FOR UPDATE/SHARE need to mark tuples */ if (queryDesc->plannedstmt->intoClause != NULL || queryDesc->plannedstmt->rowMarks != NIL) estate->es_output_cid = GetCurrentCommandId(true); break; case CMD_INSERT: case CMD_DELETE: case CMD_UPDATE: estate->es_output_cid = GetCurrentCommandId(true); break; default: elog(ERROR, "unrecognized operation code: %d", (int) queryDesc->operation); break; } /* * Copy other important information into the EState */ estate->es_snapshot = RegisterSnapshot(queryDesc->snapshot); estate->es_crosscheck_snapshot = RegisterSnapshot(queryDesc->crosscheck_snapshot); estate->es_instrument = queryDesc->doInstrument; /* * Initialize the plan state tree */ InitPlan(queryDesc, eflags); MemoryContextSwitchTo(oldcontext); } /* ---------------------------------------------------------------- * ExecutorRun * * This is the main routine of the executor module. It accepts * the query descriptor from the traffic cop and executes the * query plan. * * ExecutorStart must have been called already. * * If direction is NoMovementScanDirection then nothing is done * except to start up/shut down the destination. Otherwise, * we retrieve up to 'count' tuples in the specified direction. * * Note: count = 0 is interpreted as no portal limit, i.e., run to * completion. * * There is no return value, but output tuples (if any) are sent to * the destination receiver specified in the QueryDesc; and the number * of tuples processed at the top level can be found in * estate->es_processed. * * We provide a function hook variable that lets loadable plugins * get control when ExecutorRun is called. Such a plugin would * normally call standard_ExecutorRun(). * * ---------------------------------------------------------------- */ void ExecutorRun(QueryDesc *queryDesc, ScanDirection direction, long count) { if (ExecutorRun_hook) (*ExecutorRun_hook) (queryDesc, direction, count); else standard_ExecutorRun(queryDesc, direction, count); } void standard_ExecutorRun(QueryDesc *queryDesc, ScanDirection direction, long count) { EState *estate; CmdType operation; DestReceiver *dest; bool sendTuples; MemoryContext oldcontext; /* sanity checks */ Assert(queryDesc != NULL); estate = queryDesc->estate; Assert(estate != NULL); /* * Switch into per-query memory context */ oldcontext = MemoryContextSwitchTo(estate->es_query_cxt); /* Allow instrumentation of ExecutorRun overall runtime */ if (queryDesc->totaltime) InstrStartNode(queryDesc->totaltime); /* * extract information from the query descriptor and the query feature. */ operation = queryDesc->operation; dest = queryDesc->dest; /* * startup tuple receiver, if we will be emitting tuples */ estate->es_processed = 0; estate->es_lastoid = InvalidOid; sendTuples = (operation == CMD_SELECT || queryDesc->plannedstmt->hasReturning); if (sendTuples) (*dest->rStartup) (dest, operation, queryDesc->tupDesc); /* * run plan */ if (!ScanDirectionIsNoMovement(direction)) ExecutePlan(estate, queryDesc->planstate, operation, sendTuples, count, direction, dest); /* * shutdown tuple receiver, if we started it */ if (sendTuples) (*dest->rShutdown) (dest); if (queryDesc->totaltime) InstrStopNode(queryDesc->totaltime, estate->es_processed); MemoryContextSwitchTo(oldcontext); } /* ---------------------------------------------------------------- * ExecutorEnd * * This routine must be called at the end of execution of any * query plan * * We provide a function hook variable that lets loadable plugins * get control when ExecutorEnd is called. Such a plugin would * normally call standard_ExecutorEnd(). * * ---------------------------------------------------------------- */ void ExecutorEnd(QueryDesc *queryDesc) { if (ExecutorEnd_hook) (*ExecutorEnd_hook) (queryDesc); else standard_ExecutorEnd(queryDesc); } void standard_ExecutorEnd(QueryDesc *queryDesc) { EState *estate; MemoryContext oldcontext; /* sanity checks */ Assert(queryDesc != NULL); estate = queryDesc->estate; Assert(estate != NULL); /* * Switch into per-query memory context to run ExecEndPlan */ oldcontext = MemoryContextSwitchTo(estate->es_query_cxt); ExecEndPlan(queryDesc->planstate, estate); /* * Close the SELECT INTO relation if any */ if (estate->es_select_into) CloseIntoRel(queryDesc); /* do away with our snapshots */ UnregisterSnapshot(estate->es_snapshot); UnregisterSnapshot(estate->es_crosscheck_snapshot); /* * Must switch out of context before destroying it */ MemoryContextSwitchTo(oldcontext); /* * Release EState and per-query memory context. This should release * everything the executor has allocated. */ FreeExecutorState(estate); /* Reset queryDesc fields that no longer point to anything */ queryDesc->tupDesc = NULL; queryDesc->estate = NULL; queryDesc->planstate = NULL; queryDesc->totaltime = NULL; } /* ---------------------------------------------------------------- * ExecutorRewind * * This routine may be called on an open queryDesc to rewind it * to the start. * ---------------------------------------------------------------- */ void ExecutorRewind(QueryDesc *queryDesc) { EState *estate; MemoryContext oldcontext; /* sanity checks */ Assert(queryDesc != NULL); estate = queryDesc->estate; Assert(estate != NULL); /* It's probably not sensible to rescan updating queries */ Assert(queryDesc->operation == CMD_SELECT); /* * Switch into per-query memory context */ oldcontext = MemoryContextSwitchTo(estate->es_query_cxt); /* * rescan plan */ ExecReScan(queryDesc->planstate, NULL); MemoryContextSwitchTo(oldcontext); } /* * ExecCheckRTPerms * Check access permissions for all relations listed in a range table. */ static void ExecCheckRTPerms(List *rangeTable) { ListCell *l; foreach(l, rangeTable) { ExecCheckRTEPerms((RangeTblEntry *) lfirst(l)); } } /* * ExecCheckRTEPerms * Check access permissions for a single RTE. */ static void ExecCheckRTEPerms(RangeTblEntry *rte) { AclMode requiredPerms; AclMode relPerms; AclMode remainingPerms; Oid relOid; Oid userid; Bitmapset *tmpset; int col; /* * Only plain-relation RTEs need to be checked here. Function RTEs are * checked by init_fcache when the function is prepared for execution. * Join, subquery, and special RTEs need no checks. */ if (rte->rtekind != RTE_RELATION) return; /* * No work if requiredPerms is empty. */ requiredPerms = rte->requiredPerms; if (requiredPerms == 0) return; relOid = rte->relid; /* * userid to check as: current user unless we have a setuid indication. * * Note: GetUserId() is presently fast enough that there's no harm in * calling it separately for each RTE. If that stops being true, we could * call it once in ExecCheckRTPerms and pass the userid down from there. * But for now, no need for the extra clutter. */ userid = rte->checkAsUser ? rte->checkAsUser : GetUserId(); /* * We must have *all* the requiredPerms bits, but some of the bits can be * satisfied from column-level rather than relation-level permissions. * First, remove any bits that are satisfied by relation permissions. */ relPerms = pg_class_aclmask(relOid, userid, requiredPerms, ACLMASK_ALL); remainingPerms = requiredPerms & ~relPerms; if (remainingPerms != 0) { /* * If we lack any permissions that exist only as relation permissions, * we can fail straight away. */ if (remainingPerms & ~(ACL_SELECT | ACL_INSERT | ACL_UPDATE)) aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_CLASS, get_rel_name(relOid)); /* * Check to see if we have the needed privileges at column level. * * Note: failures just report a table-level error; it would be nicer * to report a column-level error if we have some but not all of the * column privileges. */ if (remainingPerms & ACL_SELECT) { /* * When the query doesn't explicitly reference any columns (for * example, SELECT COUNT(*) FROM table), allow the query if we * have SELECT on any column of the rel, as per SQL spec. */ if (bms_is_empty(rte->selectedCols)) { if (pg_attribute_aclcheck_all(relOid, userid, ACL_SELECT, ACLMASK_ANY) != ACLCHECK_OK) aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_CLASS, get_rel_name(relOid)); } tmpset = bms_copy(rte->selectedCols); while ((col = bms_first_member(tmpset)) >= 0) { /* remove the column number offset */ col += FirstLowInvalidHeapAttributeNumber; if (col == InvalidAttrNumber) { /* Whole-row reference, must have priv on all cols */ if (pg_attribute_aclcheck_all(relOid, userid, ACL_SELECT, ACLMASK_ALL) != ACLCHECK_OK) aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_CLASS, get_rel_name(relOid)); } else { if (pg_attribute_aclcheck(relOid, col, userid, ACL_SELECT) != ACLCHECK_OK) aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_CLASS, get_rel_name(relOid)); } } bms_free(tmpset); } /* * Basically the same for the mod columns, with either INSERT or * UPDATE privilege as specified by remainingPerms. */ remainingPerms &= ~ACL_SELECT; if (remainingPerms != 0) { /* * When the query doesn't explicitly change any columns, allow the * query if we have permission on any column of the rel. This is * to handle SELECT FOR UPDATE as well as possible corner cases in * INSERT and UPDATE. */ if (bms_is_empty(rte->modifiedCols)) { if (pg_attribute_aclcheck_all(relOid, userid, remainingPerms, ACLMASK_ANY) != ACLCHECK_OK) aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_CLASS, get_rel_name(relOid)); } tmpset = bms_copy(rte->modifiedCols); while ((col = bms_first_member(tmpset)) >= 0) { /* remove the column number offset */ col += FirstLowInvalidHeapAttributeNumber; if (col == InvalidAttrNumber) { /* whole-row reference can't happen here */ elog(ERROR, "whole-row update is not implemented"); } else { if (pg_attribute_aclcheck(relOid, col, userid, remainingPerms) != ACLCHECK_OK) aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_CLASS, get_rel_name(relOid)); } } bms_free(tmpset); } } } /* * Check that the query does not imply any writes to non-temp tables. */ static void ExecCheckXactReadOnly(PlannedStmt *plannedstmt) { ListCell *l; /* * CREATE TABLE AS or SELECT INTO? * * XXX should we allow this if the destination is temp? */ if (plannedstmt->intoClause != NULL) goto fail; /* Fail if write permissions are requested on any non-temp table */ foreach(l, plannedstmt->rtable) { RangeTblEntry *rte = (RangeTblEntry *) lfirst(l); if (rte->rtekind != RTE_RELATION) continue; if ((rte->requiredPerms & (~ACL_SELECT)) == 0) continue; if (isTempNamespace(get_rel_namespace(rte->relid))) continue; goto fail; } return; fail: ereport(ERROR, (errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION), errmsg("transaction is read-only"))); } /* ---------------------------------------------------------------- * InitPlan * * Initializes the query plan: open files, allocate storage * and start up the rule manager * ---------------------------------------------------------------- */ static void InitPlan(QueryDesc *queryDesc, int eflags) { CmdType operation = queryDesc->operation; PlannedStmt *plannedstmt = queryDesc->plannedstmt; Plan *plan = plannedstmt->planTree; List *rangeTable = plannedstmt->rtable; EState *estate = queryDesc->estate; PlanState *planstate; TupleDesc tupType; ListCell *l; int i; /* * Do permissions checks */ ExecCheckRTPerms(rangeTable); /* * initialize the node's execution state */ estate->es_range_table = rangeTable; /* * initialize result relation stuff, and open/lock the result rels. * * We must do this before initializing the plan tree, else we might * try to do a lock upgrade if a result rel is also a source rel. */ if (plannedstmt->resultRelations) { List *resultRelations = plannedstmt->resultRelations; int numResultRelations = list_length(resultRelations); ResultRelInfo *resultRelInfos; ResultRelInfo *resultRelInfo; resultRelInfos = (ResultRelInfo *) palloc(numResultRelations * sizeof(ResultRelInfo)); resultRelInfo = resultRelInfos; foreach(l, resultRelations) { Index resultRelationIndex = lfirst_int(l); Oid resultRelationOid; Relation resultRelation; resultRelationOid = getrelid(resultRelationIndex, rangeTable); resultRelation = heap_open(resultRelationOid, RowExclusiveLock); InitResultRelInfo(resultRelInfo, resultRelation, resultRelationIndex, operation, estate->es_instrument); resultRelInfo++; } estate->es_result_relations = resultRelInfos; estate->es_num_result_relations = numResultRelations; /* es_result_relation_info is NULL except when within ModifyTable */ estate->es_result_relation_info = NULL; } else { /* * if no result relation, then set state appropriately */ estate->es_result_relations = NULL; estate->es_num_result_relations = 0; estate->es_result_relation_info = NULL; } /* * Detect whether we're doing SELECT INTO. If so, set the es_into_oids * flag appropriately so that the plan tree will be initialized with the * correct tuple descriptors. (Other SELECT INTO stuff comes later.) */ estate->es_select_into = false; if (operation == CMD_SELECT && plannedstmt->intoClause != NULL) { estate->es_select_into = true; estate->es_into_oids = interpretOidsOption(plannedstmt->intoClause->options); } /* * Have to lock relations selected FOR UPDATE/FOR SHARE before we * initialize the plan tree, else we'd be doing a lock upgrade. While we * are at it, build the ExecRowMark list. */ estate->es_rowMarks = NIL; foreach(l, plannedstmt->rowMarks) { RowMarkClause *rc = (RowMarkClause *) lfirst(l); Oid relid; Relation relation; ExecRowMark *erm; /* ignore "parent" rowmarks; they are irrelevant at runtime */ if (rc->isParent) continue; relid = getrelid(rc->rti, rangeTable); relation = heap_open(relid, RowShareLock); erm = (ExecRowMark *) palloc(sizeof(ExecRowMark)); erm->relation = relation; erm->rti = rc->rti; erm->prti = rc->prti; erm->forUpdate = rc->forUpdate; erm->noWait = rc->noWait; /* We'll locate the junk attrs below */ erm->ctidAttNo = InvalidAttrNumber; erm->toidAttNo = InvalidAttrNumber; ItemPointerSetInvalid(&(erm->curCtid)); estate->es_rowMarks = lappend(estate->es_rowMarks, erm); } /* * Initialize the executor's tuple table to empty. */ estate->es_tupleTable = NIL; estate->es_trig_tuple_slot = NULL; /* mark EvalPlanQual not active */ estate->es_plannedstmt = plannedstmt; estate->es_evalPlanQual = NULL; estate->es_evTupleNull = NULL; estate->es_evTuple = NULL; estate->es_useEvalPlan = false; /* * Initialize private state information for each SubPlan. We must do this * before running ExecInitNode on the main query tree, since * ExecInitSubPlan expects to be able to find these entries. */ Assert(estate->es_subplanstates == NIL); i = 1; /* subplan indices count from 1 */ foreach(l, plannedstmt->subplans) { Plan *subplan = (Plan *) lfirst(l); PlanState *subplanstate; int sp_eflags; /* * A subplan will never need to do BACKWARD scan nor MARK/RESTORE. If * it is a parameterless subplan (not initplan), we suggest that it be * prepared to handle REWIND efficiently; otherwise there is no need. */ sp_eflags = eflags & EXEC_FLAG_EXPLAIN_ONLY; if (bms_is_member(i, plannedstmt->rewindPlanIDs)) sp_eflags |= EXEC_FLAG_REWIND; subplanstate = ExecInitNode(subplan, estate, sp_eflags); estate->es_subplanstates = lappend(estate->es_subplanstates, subplanstate); i++; } /* * Initialize the private state information for all the nodes in the query * tree. This opens files, allocates storage and leaves us ready to start * processing tuples. */ planstate = ExecInitNode(plan, estate, eflags); /* * Get the tuple descriptor describing the type of tuples to return. (this * is especially important if we are creating a relation with "SELECT * INTO") */ tupType = ExecGetResultType(planstate); /* * Initialize the junk filter if needed. SELECT queries need a * filter if there are any junk attrs in the top-level tlist. */ if (operation == CMD_SELECT) { bool junk_filter_needed = false; ListCell *tlist; foreach(tlist, plan->targetlist) { TargetEntry *tle = (TargetEntry *) lfirst(tlist); if (tle->resjunk) { junk_filter_needed = true; break; } } if (junk_filter_needed) { JunkFilter *j; j = ExecInitJunkFilter(planstate->plan->targetlist, tupType->tdhasoid, ExecInitExtraTupleSlot(estate)); estate->es_junkFilter = j; /* Want to return the cleaned tuple type */ tupType = j->jf_cleanTupType; /* For SELECT FOR UPDATE/SHARE, find the junk attrs now */ foreach(l, estate->es_rowMarks) { ExecRowMark *erm = (ExecRowMark *) lfirst(l); char resname[32]; /* always need the ctid */ snprintf(resname, sizeof(resname), "ctid%u", erm->prti); erm->ctidAttNo = ExecFindJunkAttribute(j, resname); if (!AttributeNumberIsValid(erm->ctidAttNo)) elog(ERROR, "could not find junk \"%s\" column", resname); /* if child relation, need tableoid too */ if (erm->rti != erm->prti) { snprintf(resname, sizeof(resname), "tableoid%u", erm->prti); erm->toidAttNo = ExecFindJunkAttribute(j, resname); if (!AttributeNumberIsValid(erm->toidAttNo)) elog(ERROR, "could not find junk \"%s\" column", resname); } } } else { estate->es_junkFilter = NULL; if (estate->es_rowMarks) elog(ERROR, "SELECT FOR UPDATE/SHARE, but no junk columns"); } } queryDesc->tupDesc = tupType; queryDesc->planstate = planstate; /* * If doing SELECT INTO, initialize the "into" relation. We must wait * till now so we have the "clean" result tuple type to create the new * table from. * * If EXPLAIN, skip creating the "into" relation. */ if (estate->es_select_into && !(eflags & EXEC_FLAG_EXPLAIN_ONLY)) OpenIntoRel(queryDesc); } /* * Initialize ResultRelInfo data for one result relation */ void InitResultRelInfo(ResultRelInfo *resultRelInfo, Relation resultRelationDesc, Index resultRelationIndex, CmdType operation, bool doInstrument) { /* * Check valid relkind ... parser and/or planner should have noticed this * already, but let's make sure. */ switch (resultRelationDesc->rd_rel->relkind) { case RELKIND_RELATION: /* OK */ break; case RELKIND_SEQUENCE: ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot change sequence \"%s\"", RelationGetRelationName(resultRelationDesc)))); break; case RELKIND_TOASTVALUE: ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot change TOAST relation \"%s\"", RelationGetRelationName(resultRelationDesc)))); break; case RELKIND_VIEW: ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot change view \"%s\"", RelationGetRelationName(resultRelationDesc)))); break; default: ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot change relation \"%s\"", RelationGetRelationName(resultRelationDesc)))); break; } /* OK, fill in the node */ MemSet(resultRelInfo, 0, sizeof(ResultRelInfo)); resultRelInfo->type = T_ResultRelInfo; resultRelInfo->ri_RangeTableIndex = resultRelationIndex; resultRelInfo->ri_RelationDesc = resultRelationDesc; resultRelInfo->ri_NumIndices = 0; resultRelInfo->ri_IndexRelationDescs = NULL; resultRelInfo->ri_IndexRelationInfo = NULL; /* make a copy so as not to depend on relcache info not changing... */ resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc); if (resultRelInfo->ri_TrigDesc) { int n = resultRelInfo->ri_TrigDesc->numtriggers; resultRelInfo->ri_TrigFunctions = (FmgrInfo *) palloc0(n * sizeof(FmgrInfo)); if (doInstrument) resultRelInfo->ri_TrigInstrument = InstrAlloc(n); else resultRelInfo->ri_TrigInstrument = NULL; } else { resultRelInfo->ri_TrigFunctions = NULL; resultRelInfo->ri_TrigInstrument = NULL; } resultRelInfo->ri_ConstraintExprs = NULL; resultRelInfo->ri_junkFilter = NULL; resultRelInfo->ri_projectReturning = NULL; /* * If there are indices on the result relation, open them and save * descriptors in the result relation info, so that we can add new index * entries for the tuples we add/update. We need not do this for a * DELETE, however, since deletion doesn't affect indexes. */ if (resultRelationDesc->rd_rel->relhasindex && operation != CMD_DELETE) ExecOpenIndices(resultRelInfo); } /* * ExecGetTriggerResultRel * * Get a ResultRelInfo for a trigger target relation. Most of the time, * triggers are fired on one of the result relations of the query, and so * we can just return a member of the es_result_relations array. (Note: in * self-join situations there might be multiple members with the same OID; * if so it doesn't matter which one we pick.) However, it is sometimes * necessary to fire triggers on other relations; this happens mainly when an * RI update trigger queues additional triggers on other relations, which will * be processed in the context of the outer query. For efficiency's sake, * we want to have a ResultRelInfo for those triggers too; that can avoid * repeated re-opening of the relation. (It also provides a way for EXPLAIN * ANALYZE to report the runtimes of such triggers.) So we make additional * ResultRelInfo's as needed, and save them in es_trig_target_relations. */ ResultRelInfo * ExecGetTriggerResultRel(EState *estate, Oid relid) { ResultRelInfo *rInfo; int nr; ListCell *l; Relation rel; MemoryContext oldcontext; /* First, search through the query result relations */ rInfo = estate->es_result_relations; nr = estate->es_num_result_relations; while (nr > 0) { if (RelationGetRelid(rInfo->ri_RelationDesc) == relid) return rInfo; rInfo++; nr--; } /* Nope, but maybe we already made an extra ResultRelInfo for it */ foreach(l, estate->es_trig_target_relations) { rInfo = (ResultRelInfo *) lfirst(l); if (RelationGetRelid(rInfo->ri_RelationDesc) == relid) return rInfo; } /* Nope, so we need a new one */ /* * Open the target relation's relcache entry. We assume that an * appropriate lock is still held by the backend from whenever the trigger * event got queued, so we need take no new lock here. */ rel = heap_open(relid, NoLock); /* * Make the new entry in the right context. Currently, we don't need any * index information in ResultRelInfos used only for triggers, so tell * InitResultRelInfo it's a DELETE. */ oldcontext = MemoryContextSwitchTo(estate->es_query_cxt); rInfo = makeNode(ResultRelInfo); InitResultRelInfo(rInfo, rel, 0, /* dummy rangetable index */ CMD_DELETE, estate->es_instrument); estate->es_trig_target_relations = lappend(estate->es_trig_target_relations, rInfo); MemoryContextSwitchTo(oldcontext); return rInfo; } /* * ExecContextForcesOids * * This is pretty grotty: when doing INSERT, UPDATE, or SELECT INTO, * we need to ensure that result tuples have space for an OID iff they are * going to be stored into a relation that has OIDs. In other contexts * we are free to choose whether to leave space for OIDs in result tuples * (we generally don't want to, but we do if a physical-tlist optimization * is possible). This routine checks the plan context and returns TRUE if the * choice is forced, FALSE if the choice is not forced. In the TRUE case, * *hasoids is set to the required value. * * One reason this is ugly is that all plan nodes in the plan tree will emit * tuples with space for an OID, though we really only need the topmost node * to do so. However, node types like Sort don't project new tuples but just * return their inputs, and in those cases the requirement propagates down * to the input node. Eventually we might make this code smart enough to * recognize how far down the requirement really goes, but for now we just * make all plan nodes do the same thing if the top level forces the choice. * * We assume that if we are generating tuples for INSERT or UPDATE, * estate->es_result_relation_info is already set up to describe the target * relation. Note that in an UPDATE that spans an inheritance tree, some of * the target relations may have OIDs and some not. We have to make the * decisions on a per-relation basis as we initialize each of the subplans of * the ModifyTable node, so ModifyTable has to set es_result_relation_info * while initializing each subplan. * * SELECT INTO is even uglier, because we don't have the INTO relation's * descriptor available when this code runs; we have to look aside at a * flag set by InitPlan(). */ bool ExecContextForcesOids(PlanState *planstate, bool *hasoids) { ResultRelInfo *ri = planstate->state->es_result_relation_info; if (ri != NULL) { Relation rel = ri->ri_RelationDesc; if (rel != NULL) { *hasoids = rel->rd_rel->relhasoids; return true; } } if (planstate->state->es_select_into) { *hasoids = planstate->state->es_into_oids; return true; } return false; } /* ---------------------------------------------------------------- * ExecEndPlan * * Cleans up the query plan -- closes files and frees up storage * * NOTE: we are no longer very worried about freeing storage per se * in this code; FreeExecutorState should be guaranteed to release all * memory that needs to be released. What we are worried about doing * is closing relations and dropping buffer pins. Thus, for example, * tuple tables must be cleared or dropped to ensure pins are released. * ---------------------------------------------------------------- */ static void ExecEndPlan(PlanState *planstate, EState *estate) { ResultRelInfo *resultRelInfo; int i; ListCell *l; /* * shut down any PlanQual processing we were doing */ if (estate->es_evalPlanQual != NULL) EndEvalPlanQual(estate); /* * shut down the node-type-specific query processing */ ExecEndNode(planstate); /* * for subplans too */ foreach(l, estate->es_subplanstates) { PlanState *subplanstate = (PlanState *) lfirst(l); ExecEndNode(subplanstate); } /* * destroy the executor's tuple table. Actually we only care about * releasing buffer pins and tupdesc refcounts; there's no need to * pfree the TupleTableSlots, since the containing memory context * is about to go away anyway. */ ExecResetTupleTable(estate->es_tupleTable, false); /* * close the result relation(s) if any, but hold locks until xact commit. */ resultRelInfo = estate->es_result_relations; for (i = estate->es_num_result_relations; i > 0; i--) { /* Close indices and then the relation itself */ ExecCloseIndices(resultRelInfo); heap_close(resultRelInfo->ri_RelationDesc, NoLock); resultRelInfo++; } /* * likewise close any trigger target relations */ foreach(l, estate->es_trig_target_relations) { resultRelInfo = (ResultRelInfo *) lfirst(l); /* Close indices and then the relation itself */ ExecCloseIndices(resultRelInfo); heap_close(resultRelInfo->ri_RelationDesc, NoLock); } /* * close any relations selected FOR UPDATE/FOR SHARE, again keeping locks */ foreach(l, estate->es_rowMarks) { ExecRowMark *erm = lfirst(l); heap_close(erm->relation, NoLock); } } /* ---------------------------------------------------------------- * ExecutePlan * * Processes the query plan until we have processed 'numberTuples' tuples, * moving in the specified direction. * * Runs to completion if numberTuples is 0 * * Note: the ctid attribute is a 'junk' attribute that is removed before the * user can see it * ---------------------------------------------------------------- */ static void ExecutePlan(EState *estate, PlanState *planstate, CmdType operation, bool sendTuples, long numberTuples, ScanDirection direction, DestReceiver *dest) { JunkFilter *junkfilter; TupleTableSlot *planSlot; TupleTableSlot *slot; long current_tuple_count; /* * initialize local variables */ current_tuple_count = 0; /* * Set the direction. */ estate->es_direction = direction; /* * Loop until we've processed the proper number of tuples from the plan. */ for (;;) { /* Reset the per-output-tuple exprcontext */ ResetPerTupleExprContext(estate); /* * Execute the plan and obtain a tuple */ lnext: ; if (estate->es_useEvalPlan) { planSlot = EvalPlanQualNext(estate); if (TupIsNull(planSlot)) planSlot = ExecProcNode(planstate); } else planSlot = ExecProcNode(planstate); /* * if the tuple is null, then we assume there is nothing more to * process so we just end the loop... */ if (TupIsNull(planSlot)) break; slot = planSlot; /* * If we have a junk filter, then project a new tuple with the junk * removed. * * Store this new "clean" tuple in the junkfilter's resultSlot. * (Formerly, we stored it back over the "dirty" tuple, which is WRONG * because that tuple slot has the wrong descriptor.) * * But first, extract all the junk information we need. */ if ((junkfilter = estate->es_junkFilter) != NULL) { /* * Process any FOR UPDATE or FOR SHARE locking requested. */ if (estate->es_rowMarks != NIL) { ListCell *l; lmark: ; foreach(l, estate->es_rowMarks) { ExecRowMark *erm = lfirst(l); Datum datum; bool isNull; HeapTupleData tuple; Buffer buffer; ItemPointerData update_ctid; TransactionId update_xmax; TupleTableSlot *newSlot; LockTupleMode lockmode; HTSU_Result test; /* if child rel, must check whether it produced this row */ if (erm->rti != erm->prti) { Oid tableoid; datum = ExecGetJunkAttribute(slot, erm->toidAttNo, &isNull); /* shouldn't ever get a null result... */ if (isNull) elog(ERROR, "tableoid is NULL"); tableoid = DatumGetObjectId(datum); if (tableoid != RelationGetRelid(erm->relation)) { /* this child is inactive right now */ ItemPointerSetInvalid(&(erm->curCtid)); continue; } } /* okay, fetch the tuple by ctid */ datum = ExecGetJunkAttribute(slot, erm->ctidAttNo, &isNull); /* shouldn't ever get a null result... */ if (isNull) elog(ERROR, "ctid is NULL"); tuple.t_self = *((ItemPointer) DatumGetPointer(datum)); if (erm->forUpdate) lockmode = LockTupleExclusive; else lockmode = LockTupleShared; test = heap_lock_tuple(erm->relation, &tuple, &buffer, &update_ctid, &update_xmax, estate->es_output_cid, lockmode, erm->noWait); ReleaseBuffer(buffer); switch (test) { case HeapTupleSelfUpdated: /* treat it as deleted; do not process */ goto lnext; case HeapTupleMayBeUpdated: break; case HeapTupleUpdated: if (IsXactIsoLevelSerializable) ereport(ERROR, (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE), errmsg("could not serialize access due to concurrent update"))); if (!ItemPointerEquals(&update_ctid, &tuple.t_self)) { /* updated, so look at updated version */ newSlot = EvalPlanQual(estate, erm->rti, planstate, &update_ctid, update_xmax); if (!TupIsNull(newSlot)) { slot = planSlot = newSlot; estate->es_useEvalPlan = true; goto lmark; } } /* * if tuple was deleted or PlanQual failed for * updated tuple - we must not return this tuple! */ goto lnext; default: elog(ERROR, "unrecognized heap_lock_tuple status: %u", test); } /* Remember tuple TID for WHERE CURRENT OF */ erm->curCtid = tuple.t_self; } } /* * Create a new "clean" tuple with all junk attributes removed. */ slot = ExecFilterJunk(junkfilter, slot); } /* * If we are supposed to send the tuple somewhere, do so. * (In practice this is probably always the case at this point.) */ if (sendTuples) (*dest->receiveSlot) (slot, dest); /* * Count tuples processed, if this is a SELECT. (For other operation * types, the ModifyTable plan node must count the appropriate * events.) */ if (operation == CMD_SELECT) (estate->es_processed)++; /* * check our tuple count.. if we've processed the proper number then * quit, else loop again and process more tuples. Zero numberTuples * means no limit. */ current_tuple_count++; if (numberTuples && numberTuples == current_tuple_count) break; } } /* * ExecRelCheck --- check that tuple meets constraints for result relation */ static const char * ExecRelCheck(ResultRelInfo *resultRelInfo, TupleTableSlot *slot, EState *estate) { Relation rel = resultRelInfo->ri_RelationDesc; int ncheck = rel->rd_att->constr->num_check; ConstrCheck *check = rel->rd_att->constr->check; ExprContext *econtext; MemoryContext oldContext; List *qual; int i; /* * If first time through for this result relation, build expression * nodetrees for rel's constraint expressions. Keep them in the per-query * memory context so they'll survive throughout the query. */ if (resultRelInfo->ri_ConstraintExprs == NULL) { oldContext = MemoryContextSwitchTo(estate->es_query_cxt); resultRelInfo->ri_ConstraintExprs = (List **) palloc(ncheck * sizeof(List *)); for (i = 0; i < ncheck; i++) { /* ExecQual wants implicit-AND form */ qual = make_ands_implicit(stringToNode(check[i].ccbin)); resultRelInfo->ri_ConstraintExprs[i] = (List *) ExecPrepareExpr((Expr *) qual, estate); } MemoryContextSwitchTo(oldContext); } /* * We will use the EState's per-tuple context for evaluating constraint * expressions (creating it if it's not already there). */ econtext = GetPerTupleExprContext(estate); /* Arrange for econtext's scan tuple to be the tuple under test */ econtext->ecxt_scantuple = slot; /* And evaluate the constraints */ for (i = 0; i < ncheck; i++) { qual = resultRelInfo->ri_ConstraintExprs[i]; /* * NOTE: SQL92 specifies that a NULL result from a constraint * expression is not to be treated as a failure. Therefore, tell * ExecQual to return TRUE for NULL. */ if (!ExecQual(qual, econtext, true)) return check[i].ccname; } /* NULL result means no error */ return NULL; } void ExecConstraints(ResultRelInfo *resultRelInfo, TupleTableSlot *slot, EState *estate) { Relation rel = resultRelInfo->ri_RelationDesc; TupleConstr *constr = rel->rd_att->constr; Assert(constr); if (constr->has_not_null) { int natts = rel->rd_att->natts; int attrChk; for (attrChk = 1; attrChk <= natts; attrChk++) { if (rel->rd_att->attrs[attrChk - 1]->attnotnull && slot_attisnull(slot, attrChk)) ereport(ERROR, (errcode(ERRCODE_NOT_NULL_VIOLATION), errmsg("null value in column \"%s\" violates not-null constraint", NameStr(rel->rd_att->attrs[attrChk - 1]->attname)))); } } if (constr->num_check > 0) { const char *failed; if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL) ereport(ERROR, (errcode(ERRCODE_CHECK_VIOLATION), errmsg("new row for relation \"%s\" violates check constraint \"%s\"", RelationGetRelationName(rel), failed))); } } /* * Check a modified tuple to see if we want to process its updated version * under READ COMMITTED rules. * * See backend/executor/README for some info about how this works. * * estate - executor state data * rti - rangetable index of table containing tuple * subplanstate - portion of plan tree that needs to be re-evaluated * *tid - t_ctid from the outdated tuple (ie, next updated version) * priorXmax - t_xmax from the outdated tuple * * *tid is also an output parameter: it's modified to hold the TID of the * latest version of the tuple (note this may be changed even on failure) * * Returns a slot containing the new candidate update/delete tuple, or * NULL if we determine we shouldn't process the row. */ TupleTableSlot * EvalPlanQual(EState *estate, Index rti, PlanState *subplanstate, ItemPointer tid, TransactionId priorXmax) { evalPlanQual *epq; EState *epqstate; Relation relation; HeapTupleData tuple; HeapTuple copyTuple = NULL; SnapshotData SnapshotDirty; bool endNode; Assert(rti != 0); /* * find relation containing target tuple */ if (estate->es_result_relation_info != NULL && estate->es_result_relation_info->ri_RangeTableIndex == rti) relation = estate->es_result_relation_info->ri_RelationDesc; else { ListCell *l; relation = NULL; foreach(l, estate->es_rowMarks) { ExecRowMark *erm = lfirst(l); if (erm->rti == rti) { relation = erm->relation; break; } } if (relation == NULL) elog(ERROR, "could not find RowMark for RT index %u", rti); } /* * fetch tid tuple * * Loop here to deal with updated or busy tuples */ InitDirtySnapshot(SnapshotDirty); tuple.t_self = *tid; for (;;) { Buffer buffer; if (heap_fetch(relation, &SnapshotDirty, &tuple, &buffer, true, NULL)) { /* * If xmin isn't what we're expecting, the slot must have been * recycled and reused for an unrelated tuple. This implies that * the latest version of the row was deleted, so we need do * nothing. (Should be safe to examine xmin without getting * buffer's content lock, since xmin never changes in an existing * tuple.) */ if (!TransactionIdEquals(HeapTupleHeaderGetXmin(tuple.t_data), priorXmax)) { ReleaseBuffer(buffer); return NULL; } /* otherwise xmin should not be dirty... */ if (TransactionIdIsValid(SnapshotDirty.xmin)) elog(ERROR, "t_xmin is uncommitted in tuple to be updated"); /* * If tuple is being updated by other transaction then we have to * wait for its commit/abort. */ if (TransactionIdIsValid(SnapshotDirty.xmax)) { ReleaseBuffer(buffer); XactLockTableWait(SnapshotDirty.xmax); continue; /* loop back to repeat heap_fetch */ } /* * If tuple was inserted by our own transaction, we have to check * cmin against es_output_cid: cmin >= current CID means our * command cannot see the tuple, so we should ignore it. Without * this we are open to the "Halloween problem" of indefinitely * re-updating the same tuple. (We need not check cmax because * HeapTupleSatisfiesDirty will consider a tuple deleted by our * transaction dead, regardless of cmax.) We just checked that * priorXmax == xmin, so we can test that variable instead of * doing HeapTupleHeaderGetXmin again. */ if (TransactionIdIsCurrentTransactionId(priorXmax) && HeapTupleHeaderGetCmin(tuple.t_data) >= estate->es_output_cid) { ReleaseBuffer(buffer); return NULL; } /* * We got tuple - now copy it for use by recheck query. */ copyTuple = heap_copytuple(&tuple); ReleaseBuffer(buffer); break; } /* * If the referenced slot was actually empty, the latest version of * the row must have been deleted, so we need do nothing. */ if (tuple.t_data == NULL) { ReleaseBuffer(buffer); return NULL; } /* * As above, if xmin isn't what we're expecting, do nothing. */ if (!TransactionIdEquals(HeapTupleHeaderGetXmin(tuple.t_data), priorXmax)) { ReleaseBuffer(buffer); return NULL; } /* * If we get here, the tuple was found but failed SnapshotDirty. * Assuming the xmin is either a committed xact or our own xact (as it * certainly should be if we're trying to modify the tuple), this must * mean that the row was updated or deleted by either a committed xact * or our own xact. If it was deleted, we can ignore it; if it was * updated then chain up to the next version and repeat the whole * test. * * As above, it should be safe to examine xmax and t_ctid without the * buffer content lock, because they can't be changing. */ if (ItemPointerEquals(&tuple.t_self, &tuple.t_data->t_ctid)) { /* deleted, so forget about it */ ReleaseBuffer(buffer); return NULL; } /* updated, so look at the updated row */ tuple.t_self = tuple.t_data->t_ctid; /* updated row should have xmin matching this xmax */ priorXmax = HeapTupleHeaderGetXmax(tuple.t_data); ReleaseBuffer(buffer); /* loop back to fetch next in chain */ } /* * For UPDATE/DELETE we have to return tid of actual row we're executing * PQ for. */ *tid = tuple.t_self; /* * Need to run a recheck subquery. Find or create a PQ stack entry. */ epq = estate->es_evalPlanQual; endNode = true; if (epq != NULL && epq->rti == 0) { /* Top PQ stack entry is idle, so re-use it */ Assert(!(estate->es_useEvalPlan) && epq->next == NULL); epq->rti = rti; endNode = false; } /* * If this is request for another RTE - Ra, - then we have to check wasn't * PlanQual requested for Ra already and if so then Ra' row was updated * again and we have to re-start old execution for Ra and forget all what * we done after Ra was suspended. Cool? -:)) */ if (epq != NULL && epq->rti != rti && epq->estate->es_evTuple[rti - 1] != NULL) { do { evalPlanQual *oldepq; /* stop execution */ EvalPlanQualStop(epq); /* pop previous PlanQual from the stack */ oldepq = epq->next; Assert(oldepq && oldepq->rti != 0); /* push current PQ to freePQ stack */ oldepq->free = epq; epq = oldepq; estate->es_evalPlanQual = epq; } while (epq->rti != rti); } /* * If we are requested for another RTE then we have to suspend execution * of current PlanQual and start execution for new one. */ if (epq == NULL || epq->rti != rti) { /* try to reuse plan used previously */ evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL; if (newepq == NULL) /* first call or freePQ stack is empty */ { newepq = (evalPlanQual *) palloc0(sizeof(evalPlanQual)); newepq->free = NULL; newepq->estate = NULL; newepq->planstate = NULL; } else { /* recycle previously used PlanQual */ Assert(newepq->estate == NULL); epq->free = NULL; } /* push current PQ to the stack */ newepq->next = epq; epq = newepq; estate->es_evalPlanQual = epq; epq->rti = rti; endNode = false; } Assert(epq->rti == rti); /* * Ok - we're requested for the same RTE. Unfortunately we still have to * end and restart execution of the plan, because ExecReScan wouldn't * ensure that upper plan nodes would reset themselves. We could make * that work if insertion of the target tuple were integrated with the * Param mechanism somehow, so that the upper plan nodes know that their * children's outputs have changed. * * Note that the stack of free evalPlanQual nodes is quite useless at the * moment, since it only saves us from pallocing/releasing the * evalPlanQual nodes themselves. But it will be useful once we implement * ReScan instead of end/restart for re-using PlanQual nodes. */ if (endNode) { /* stop execution */ EvalPlanQualStop(epq); } /* * Initialize new recheck query. * * Note: if we were re-using PlanQual plans via ExecReScan, we'd need to * instead copy down changeable state from the top plan (including * es_result_relation_info) and reset locally changeable * state in the epq (including es_param_exec_vals, es_evTupleNull). */ EvalPlanQualStart(epq, estate, subplanstate->plan, epq->next); /* * free old RTE' tuple, if any, and store target tuple where relation's * scan node will see it */ epqstate = epq->estate; if (epqstate->es_evTuple[rti - 1] != NULL) heap_freetuple(epqstate->es_evTuple[rti - 1]); epqstate->es_evTuple[rti - 1] = copyTuple; return EvalPlanQualNext(estate); } static TupleTableSlot * EvalPlanQualNext(EState *estate) { evalPlanQual *epq = estate->es_evalPlanQual; MemoryContext oldcontext; TupleTableSlot *slot; Assert(epq->rti != 0); lpqnext:; oldcontext = MemoryContextSwitchTo(epq->estate->es_query_cxt); slot = ExecProcNode(epq->planstate); MemoryContextSwitchTo(oldcontext); /* * No more tuples for this PQ. Continue previous one. */ if (TupIsNull(slot)) { evalPlanQual *oldepq; /* stop execution */ EvalPlanQualStop(epq); /* pop old PQ from the stack */ oldepq = epq->next; if (oldepq == NULL) { /* this is the first (oldest) PQ - mark as free */ epq->rti = 0; estate->es_useEvalPlan = false; /* and continue Query execution */ return NULL; } Assert(oldepq->rti != 0); /* push current PQ to freePQ stack */ oldepq->free = epq; epq = oldepq; estate->es_evalPlanQual = epq; goto lpqnext; } return slot; } static void EndEvalPlanQual(EState *estate) { evalPlanQual *epq = estate->es_evalPlanQual; if (epq->rti == 0) /* plans already shutdowned */ { Assert(epq->next == NULL); return; } for (;;) { evalPlanQual *oldepq; /* stop execution */ EvalPlanQualStop(epq); /* pop old PQ from the stack */ oldepq = epq->next; if (oldepq == NULL) { /* this is the first (oldest) PQ - mark as free */ epq->rti = 0; estate->es_useEvalPlan = false; break; } Assert(oldepq->rti != 0); /* push current PQ to freePQ stack */ oldepq->free = epq; epq = oldepq; estate->es_evalPlanQual = epq; } } /* * Start execution of one level of PlanQual. * * This is a cut-down version of ExecutorStart(): we copy some state from * the top-level estate rather than initializing it fresh. */ static void EvalPlanQualStart(evalPlanQual *epq, EState *estate, Plan *planTree, evalPlanQual *priorepq) { EState *epqstate; int rtsize; MemoryContext oldcontext; ListCell *l; rtsize = list_length(estate->es_range_table); epq->estate = epqstate = CreateExecutorState(); oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt); /* * The epqstates share the top query's copy of unchanging state such as * the snapshot, rangetable, result-rel info, and external Param info. * They need their own copies of local state, including a tuple table, * es_param_exec_vals, etc. */ epqstate->es_direction = ForwardScanDirection; epqstate->es_snapshot = estate->es_snapshot; epqstate->es_crosscheck_snapshot = estate->es_crosscheck_snapshot; epqstate->es_range_table = estate->es_range_table; epqstate->es_output_cid = estate->es_output_cid; epqstate->es_result_relations = estate->es_result_relations; epqstate->es_num_result_relations = estate->es_num_result_relations; epqstate->es_result_relation_info = estate->es_result_relation_info; epqstate->es_junkFilter = estate->es_junkFilter; /* es_trig_target_relations must NOT be copied */ epqstate->es_param_list_info = estate->es_param_list_info; if (estate->es_plannedstmt->nParamExec > 0) epqstate->es_param_exec_vals = (ParamExecData *) palloc0(estate->es_plannedstmt->nParamExec * sizeof(ParamExecData)); epqstate->es_rowMarks = estate->es_rowMarks; epqstate->es_instrument = estate->es_instrument; epqstate->es_select_into = estate->es_select_into; epqstate->es_into_oids = estate->es_into_oids; epqstate->es_plannedstmt = estate->es_plannedstmt; /* * Each epqstate must have its own es_evTupleNull state, but all the stack * entries share es_evTuple state. This allows sub-rechecks to inherit * the value being examined by an outer recheck. */ epqstate->es_evTupleNull = (bool *) palloc0(rtsize * sizeof(bool)); if (priorepq == NULL) /* first PQ stack entry */ epqstate->es_evTuple = (HeapTuple *) palloc0(rtsize * sizeof(HeapTuple)); else /* later stack entries share the same storage */ epqstate->es_evTuple = priorepq->estate->es_evTuple; /* * Each epqstate also has its own tuple table. */ epqstate->es_tupleTable = NIL; /* * Initialize private state information for each SubPlan. We must do this * before running ExecInitNode on the main query tree, since * ExecInitSubPlan expects to be able to find these entries. * Some of the SubPlans might not be used in the part of the plan tree * we intend to run, but since it's not easy to tell which, we just * initialize them all. */ Assert(epqstate->es_subplanstates == NIL); foreach(l, estate->es_plannedstmt->subplans) { Plan *subplan = (Plan *) lfirst(l); PlanState *subplanstate; subplanstate = ExecInitNode(subplan, epqstate, 0); epqstate->es_subplanstates = lappend(epqstate->es_subplanstates, subplanstate); } /* * Initialize the private state information for all the nodes in the * part of the plan tree we need to run. This opens files, allocates * storage and leaves us ready to start processing tuples. */ epq->planstate = ExecInitNode(planTree, epqstate, 0); MemoryContextSwitchTo(oldcontext); } /* * End execution of one level of PlanQual. * * This is a cut-down version of ExecutorEnd(); basically we want to do most * of the normal cleanup, but *not* close result relations (which we are * just sharing from the outer query). We do, however, have to close any * trigger target relations that got opened, since those are not shared. */ static void EvalPlanQualStop(evalPlanQual *epq) { EState *epqstate = epq->estate; MemoryContext oldcontext; ListCell *l; oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt); ExecEndNode(epq->planstate); foreach(l, epqstate->es_subplanstates) { PlanState *subplanstate = (PlanState *) lfirst(l); ExecEndNode(subplanstate); } /* throw away the per-epqstate tuple table completely */ ExecResetTupleTable(epqstate->es_tupleTable, true); epqstate->es_tupleTable = NIL; if (epqstate->es_evTuple[epq->rti - 1] != NULL) { heap_freetuple(epqstate->es_evTuple[epq->rti - 1]); epqstate->es_evTuple[epq->rti - 1] = NULL; } foreach(l, epqstate->es_trig_target_relations) { ResultRelInfo *resultRelInfo = (ResultRelInfo *) lfirst(l); /* Close indices and then the relation itself */ ExecCloseIndices(resultRelInfo); heap_close(resultRelInfo->ri_RelationDesc, NoLock); } MemoryContextSwitchTo(oldcontext); FreeExecutorState(epqstate); epq->estate = NULL; epq->planstate = NULL; } /* * ExecGetActivePlanTree --- get the active PlanState tree from a QueryDesc * * Ordinarily this is just the one mentioned in the QueryDesc, but if we * are looking at a row returned by the EvalPlanQual machinery, we need * to look at the subsidiary state instead. */ PlanState * ExecGetActivePlanTree(QueryDesc *queryDesc) { EState *estate = queryDesc->estate; if (estate && estate->es_useEvalPlan && estate->es_evalPlanQual != NULL) return estate->es_evalPlanQual->planstate; else return queryDesc->planstate; } /* * Support for SELECT INTO (a/k/a CREATE TABLE AS) * * We implement SELECT INTO by diverting SELECT's normal output with * a specialized DestReceiver type. */ typedef struct { DestReceiver pub; /* publicly-known function pointers */ EState *estate; /* EState we are working with */ Relation rel; /* Relation to write to */ int hi_options; /* heap_insert performance options */ BulkInsertState bistate; /* bulk insert state */ } DR_intorel; /* * OpenIntoRel --- actually create the SELECT INTO target relation * * This also replaces QueryDesc->dest with the special DestReceiver for * SELECT INTO. We assume that the correct result tuple type has already * been placed in queryDesc->tupDesc. */ static void OpenIntoRel(QueryDesc *queryDesc) { IntoClause *into = queryDesc->plannedstmt->intoClause; EState *estate = queryDesc->estate; Relation intoRelationDesc; char *intoName; Oid namespaceId; Oid tablespaceId; Datum reloptions; AclResult aclresult; Oid intoRelationId; TupleDesc tupdesc; DR_intorel *myState; static char *validnsps[] = HEAP_RELOPT_NAMESPACES; Assert(into); /* * Check consistency of arguments */ if (into->onCommit != ONCOMMIT_NOOP && !into->rel->istemp) ereport(ERROR, (errcode(ERRCODE_INVALID_TABLE_DEFINITION), errmsg("ON COMMIT can only be used on temporary tables"))); /* * Find namespace to create in, check its permissions */ intoName = into->rel->relname; namespaceId = RangeVarGetCreationNamespace(into->rel); aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(), ACL_CREATE); if (aclresult != ACLCHECK_OK) aclcheck_error(aclresult, ACL_KIND_NAMESPACE, get_namespace_name(namespaceId)); /* * Select tablespace to use. If not specified, use default tablespace * (which may in turn default to database's default). */ if (into->tableSpaceName) { tablespaceId = get_tablespace_oid(into->tableSpaceName); if (!OidIsValid(tablespaceId)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("tablespace \"%s\" does not exist", into->tableSpaceName))); } else { tablespaceId = GetDefaultTablespace(into->rel->istemp); /* note InvalidOid is OK in this case */ } /* Check permissions except when using the database's default space */ if (OidIsValid(tablespaceId) && tablespaceId != MyDatabaseTableSpace) { AclResult aclresult; aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(), ACL_CREATE); if (aclresult != ACLCHECK_OK) aclcheck_error(aclresult, ACL_KIND_TABLESPACE, get_tablespace_name(tablespaceId)); } /* Parse and validate any reloptions */ reloptions = transformRelOptions((Datum) 0, into->options, NULL, validnsps, true, false); (void) heap_reloptions(RELKIND_RELATION, reloptions, true); /* Copy the tupdesc because heap_create_with_catalog modifies it */ tupdesc = CreateTupleDescCopy(queryDesc->tupDesc); /* Now we can actually create the new relation */ intoRelationId = heap_create_with_catalog(intoName, namespaceId, tablespaceId, InvalidOid, InvalidOid, GetUserId(), tupdesc, NIL, RELKIND_RELATION, false, true, 0, into->onCommit, reloptions, true, allowSystemTableMods); FreeTupleDesc(tupdesc); /* * Advance command counter so that the newly-created relation's catalog * tuples will be visible to heap_open. */ CommandCounterIncrement(); /* * If necessary, create a TOAST table for the INTO relation. Note that * AlterTableCreateToastTable ends with CommandCounterIncrement(), so that * the TOAST table will be visible for insertion. */ reloptions = transformRelOptions((Datum) 0, into->options, "toast", validnsps, true, false); (void) heap_reloptions(RELKIND_TOASTVALUE, reloptions, true); AlterTableCreateToastTable(intoRelationId, InvalidOid, reloptions, false); /* * And open the constructed table for writing. */ intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock); /* * Now replace the query's DestReceiver with one for SELECT INTO */ queryDesc->dest = CreateDestReceiver(DestIntoRel); myState = (DR_intorel *) queryDesc->dest; Assert(myState->pub.mydest == DestIntoRel); myState->estate = estate; myState->rel = intoRelationDesc; /* * We can skip WAL-logging the insertions, unless PITR is in use. We can * skip the FSM in any case. */ myState->hi_options = HEAP_INSERT_SKIP_FSM | (XLogArchivingActive() ? 0 : HEAP_INSERT_SKIP_WAL); myState->bistate = GetBulkInsertState(); /* Not using WAL requires rd_targblock be initially invalid */ Assert(intoRelationDesc->rd_targblock == InvalidBlockNumber); } /* * CloseIntoRel --- clean up SELECT INTO at ExecutorEnd time */ static void CloseIntoRel(QueryDesc *queryDesc) { DR_intorel *myState = (DR_intorel *) queryDesc->dest; /* OpenIntoRel might never have gotten called */ if (myState && myState->pub.mydest == DestIntoRel && myState->rel) { FreeBulkInsertState(myState->bistate); /* If we skipped using WAL, must heap_sync before commit */ if (myState->hi_options & HEAP_INSERT_SKIP_WAL) heap_sync(myState->rel); /* close rel, but keep lock until commit */ heap_close(myState->rel, NoLock); myState->rel = NULL; } } /* * CreateIntoRelDestReceiver -- create a suitable DestReceiver object */ DestReceiver * CreateIntoRelDestReceiver(void) { DR_intorel *self = (DR_intorel *) palloc0(sizeof(DR_intorel)); self->pub.receiveSlot = intorel_receive; self->pub.rStartup = intorel_startup; self->pub.rShutdown = intorel_shutdown; self->pub.rDestroy = intorel_destroy; self->pub.mydest = DestIntoRel; /* private fields will be set by OpenIntoRel */ return (DestReceiver *) self; } /* * intorel_startup --- executor startup */ static void intorel_startup(DestReceiver *self, int operation, TupleDesc typeinfo) { /* no-op */ } /* * intorel_receive --- receive one tuple */ static void intorel_receive(TupleTableSlot *slot, DestReceiver *self) { DR_intorel *myState = (DR_intorel *) self; HeapTuple tuple; /* * get the heap tuple out of the tuple table slot, making sure we have a * writable copy */ tuple = ExecMaterializeSlot(slot); /* * force assignment of new OID (see comments in ExecInsert) */ if (myState->rel->rd_rel->relhasoids) HeapTupleSetOid(tuple, InvalidOid); heap_insert(myState->rel, tuple, myState->estate->es_output_cid, myState->hi_options, myState->bistate); /* We know this is a newly created relation, so there are no indexes */ } /* * intorel_shutdown --- executor end */ static void intorel_shutdown(DestReceiver *self) { /* no-op */ } /* * intorel_destroy --- release DestReceiver object */ static void intorel_destroy(DestReceiver *self) { pfree(self); }