/*------------------------------------------------------------------------- * * execMain.c * top level executor interface routines * * INTERFACE ROUTINES * ExecutorStart() * ExecutorRun() * ExecutorFinish() * ExecutorEnd() * * These four procedures are the external interface 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 must always be called at the end of * execution of a plan (unless it is aborted due to error). * * ExecutorRun accepts direction and count arguments that specify whether * the plan is to be executed forwards, backwards, and for how many tuples. * In some cases ExecutorRun may be called multiple times to process all * the tuples for a plan. It is also acceptable to stop short of executing * the whole plan (but only if it is a SELECT). * * ExecutorFinish must be called after the final ExecutorRun call and * before ExecutorEnd. This can be omitted only in case of EXPLAIN, * which should also omit ExecutorRun. * * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * src/backend/executor/execMain.c * *------------------------------------------------------------------------- */ #include "postgres.h" #include "access/sysattr.h" #include "access/table.h" #include "access/tableam.h" #include "access/xact.h" #include "catalog/namespace.h" #include "catalog/partition.h" #include "commands/matview.h" #include "commands/trigger.h" #include "executor/executor.h" #include "executor/execPartition.h" #include "executor/nodeSubplan.h" #include "foreign/fdwapi.h" #include "mb/pg_wchar.h" #include "miscadmin.h" #include "nodes/queryjumble.h" #include "parser/parse_relation.h" #include "pgstat.h" #include "rewrite/rewriteHandler.h" #include "tcop/utility.h" #include "utils/acl.h" #include "utils/backend_status.h" #include "utils/lsyscache.h" #include "utils/partcache.h" #include "utils/rls.h" #include "utils/snapmgr.h" /* Hooks for plugins to get control in ExecutorStart/Run/Finish/End */ ExecutorStart_hook_type ExecutorStart_hook = NULL; ExecutorRun_hook_type ExecutorRun_hook = NULL; ExecutorFinish_hook_type ExecutorFinish_hook = NULL; ExecutorEnd_hook_type ExecutorEnd_hook = NULL; /* Hook for plugin to get control in ExecCheckPermissions() */ ExecutorCheckPerms_hook_type ExecutorCheckPerms_hook = NULL; /* decls for local routines only used within this module */ static void InitPlan(QueryDesc *queryDesc, int eflags); static void CheckValidRowMarkRel(Relation rel, RowMarkType markType); static void ExecPostprocessPlan(EState *estate); static void ExecEndPlan(PlanState *planstate, EState *estate); static void ExecutePlan(QueryDesc *queryDesc, CmdType operation, bool sendTuples, uint64 numberTuples, ScanDirection direction, DestReceiver *dest); static bool ExecCheckOneRelPerms(RTEPermissionInfo *perminfo); static bool ExecCheckPermissionsModified(Oid relOid, Oid userid, Bitmapset *modifiedCols, AclMode requiredPerms); static void ExecCheckXactReadOnly(PlannedStmt *plannedstmt); static void EvalPlanQualStart(EPQState *epqstate, Plan *planTree); static void ReportNotNullViolationError(ResultRelInfo *resultRelInfo, TupleTableSlot *slot, EState *estate, int attnum); /* 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 (which is separate * only because some places use QueryDescs for utility commands). 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) { /* * In some cases (e.g. an EXECUTE statement or an execute message with the * extended query protocol) the query_id won't be reported, so do it now. * * Note that it's harmless to report the query_id multiple times, as the * call will be ignored if the top level query_id has already been * reported. */ pgstat_report_query_id(queryDesc->plannedstmt->queryId, false); 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); /* caller must ensure the query's snapshot is active */ Assert(GetActiveSnapshot() == queryDesc->snapshot); /* * If the transaction is read-only, we need to check if any writes are * planned to non-temporary tables. EXPLAIN is considered read-only. * * Don't allow writes in parallel mode. Supporting UPDATE and DELETE * would require (a) storing the combo CID hash in shared memory, rather * than synchronizing it just once at the start of parallelism, and (b) an * alternative to heap_update()'s reliance on xmax for mutual exclusion. * INSERT may have no such troubles, but we forbid it to simplify the * checks. * * We have lower-level defenses in CommandCounterIncrement and elsewhere * against performing unsafe operations in parallel mode, but this gives a * more user-friendly error message. */ if ((XactReadOnly || IsInParallelMode()) && !(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 external parameters, if any, from queryDesc; and allocate * workspace for internal parameters */ estate->es_param_list_info = queryDesc->params; if (queryDesc->plannedstmt->paramExecTypes != NIL) { int nParamExec; nParamExec = list_length(queryDesc->plannedstmt->paramExecTypes); estate->es_param_exec_vals = (ParamExecData *) palloc0(nParamExec * sizeof(ParamExecData)); } /* We now require all callers to provide sourceText */ Assert(queryDesc->sourceText != NULL); estate->es_sourceText = queryDesc->sourceText; /* * Fill in the query environment, if any, from queryDesc. */ estate->es_queryEnv = queryDesc->queryEnv; /* * If non-read-only query, set the command ID to mark output tuples with */ switch (queryDesc->operation) { case CMD_SELECT: /* * SELECT FOR [KEY] UPDATE/SHARE and modifying CTEs need to mark * tuples */ if (queryDesc->plannedstmt->rowMarks != NIL || queryDesc->plannedstmt->hasModifyingCTE) estate->es_output_cid = GetCurrentCommandId(true); /* * A SELECT without modifying CTEs can't possibly queue triggers, * so force skip-triggers mode. This is just a marginal efficiency * hack, since AfterTriggerBeginQuery/AfterTriggerEndQuery aren't * all that expensive, but we might as well do it. */ if (!queryDesc->plannedstmt->hasModifyingCTE) eflags |= EXEC_FLAG_SKIP_TRIGGERS; break; case CMD_INSERT: case CMD_DELETE: case CMD_UPDATE: case CMD_MERGE: 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_top_eflags = eflags; estate->es_instrument = queryDesc->instrument_options; estate->es_jit_flags = queryDesc->plannedstmt->jitFlags; /* * Set up an AFTER-trigger statement context, unless told not to, or * unless it's EXPLAIN-only mode (when ExecutorFinish won't be called). */ if (!(eflags & (EXEC_FLAG_SKIP_TRIGGERS | EXEC_FLAG_EXPLAIN_ONLY))) AfterTriggerBeginQuery(); /* * 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. Also note that the count limit is only applied to * retrieved tuples, not for instance to those inserted/updated/deleted * by a ModifyTable plan node. * * 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. The total number of tuples processed in all * the ExecutorRun calls can be found in estate->es_total_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, uint64 count) { if (ExecutorRun_hook) (*ExecutorRun_hook) (queryDesc, direction, count); else standard_ExecutorRun(queryDesc, direction, count); } void standard_ExecutorRun(QueryDesc *queryDesc, ScanDirection direction, uint64 count) { EState *estate; CmdType operation; DestReceiver *dest; bool sendTuples; MemoryContext oldcontext; /* sanity checks */ Assert(queryDesc != NULL); estate = queryDesc->estate; Assert(estate != NULL); Assert(!(estate->es_top_eflags & EXEC_FLAG_EXPLAIN_ONLY)); /* caller must ensure the query's snapshot is active */ Assert(GetActiveSnapshot() == estate->es_snapshot); /* * Switch into per-query memory context */ oldcontext = MemoryContextSwitchTo(estate->es_query_cxt); /* Allow instrumentation of Executor 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; sendTuples = (operation == CMD_SELECT || queryDesc->plannedstmt->hasReturning); if (sendTuples) dest->rStartup(dest, operation, queryDesc->tupDesc); /* * Run plan, unless direction is NoMovement. * * Note: pquery.c selects NoMovement if a prior call already reached * end-of-data in the user-specified fetch direction. This is important * because various parts of the executor can misbehave if called again * after reporting EOF. For example, heapam.c would actually restart a * heapscan and return all its data afresh. There is also some doubt * about whether a parallel plan would operate properly if an additional, * necessarily non-parallel execution request occurs after completing a * parallel execution. (That case should work, but it's untested.) */ if (!ScanDirectionIsNoMovement(direction)) ExecutePlan(queryDesc, operation, sendTuples, count, direction, dest); /* * Update es_total_processed to keep track of the number of tuples * processed across multiple ExecutorRun() calls. */ estate->es_total_processed += estate->es_processed; /* * shutdown tuple receiver, if we started it */ if (sendTuples) dest->rShutdown(dest); if (queryDesc->totaltime) InstrStopNode(queryDesc->totaltime, estate->es_processed); MemoryContextSwitchTo(oldcontext); } /* ---------------------------------------------------------------- * ExecutorFinish * * This routine must be called after the last ExecutorRun call. * It performs cleanup such as firing AFTER triggers. It is * separate from ExecutorEnd because EXPLAIN ANALYZE needs to * include these actions in the total runtime. * * We provide a function hook variable that lets loadable plugins * get control when ExecutorFinish is called. Such a plugin would * normally call standard_ExecutorFinish(). * * ---------------------------------------------------------------- */ void ExecutorFinish(QueryDesc *queryDesc) { if (ExecutorFinish_hook) (*ExecutorFinish_hook) (queryDesc); else standard_ExecutorFinish(queryDesc); } void standard_ExecutorFinish(QueryDesc *queryDesc) { EState *estate; MemoryContext oldcontext; /* sanity checks */ Assert(queryDesc != NULL); estate = queryDesc->estate; Assert(estate != NULL); Assert(!(estate->es_top_eflags & EXEC_FLAG_EXPLAIN_ONLY)); /* This should be run once and only once per Executor instance */ Assert(!estate->es_finished); /* Switch into per-query memory context */ oldcontext = MemoryContextSwitchTo(estate->es_query_cxt); /* Allow instrumentation of Executor overall runtime */ if (queryDesc->totaltime) InstrStartNode(queryDesc->totaltime); /* Run ModifyTable nodes to completion */ ExecPostprocessPlan(estate); /* Execute queued AFTER triggers, unless told not to */ if (!(estate->es_top_eflags & EXEC_FLAG_SKIP_TRIGGERS)) AfterTriggerEndQuery(estate); if (queryDesc->totaltime) InstrStopNode(queryDesc->totaltime, 0); MemoryContextSwitchTo(oldcontext); estate->es_finished = true; } /* ---------------------------------------------------------------- * 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); if (estate->es_parallel_workers_to_launch > 0) pgstat_update_parallel_workers_stats((PgStat_Counter) estate->es_parallel_workers_to_launch, (PgStat_Counter) estate->es_parallel_workers_launched); /* * Check that ExecutorFinish was called, unless in EXPLAIN-only mode. This * Assert is needed because ExecutorFinish is new as of 9.1, and callers * might forget to call it. */ Assert(estate->es_finished || (estate->es_top_eflags & EXEC_FLAG_EXPLAIN_ONLY)); /* * Switch into per-query memory context to run ExecEndPlan */ oldcontext = MemoryContextSwitchTo(estate->es_query_cxt); ExecEndPlan(queryDesc->planstate, estate); /* 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); MemoryContextSwitchTo(oldcontext); } /* * ExecCheckPermissions * Check access permissions of relations mentioned in a query * * Returns true if permissions are adequate. Otherwise, throws an appropriate * error if ereport_on_violation is true, or simply returns false otherwise. * * Note that this does NOT address row-level security policies (aka: RLS). If * rows will be returned to the user as a result of this permission check * passing, then RLS also needs to be consulted (and check_enable_rls()). * * See rewrite/rowsecurity.c. * * NB: rangeTable is no longer used by us, but kept around for the hooks that * might still want to look at the RTEs. */ bool ExecCheckPermissions(List *rangeTable, List *rteperminfos, bool ereport_on_violation) { ListCell *l; bool result = true; #ifdef USE_ASSERT_CHECKING Bitmapset *indexset = NULL; /* Check that rteperminfos is consistent with rangeTable */ foreach(l, rangeTable) { RangeTblEntry *rte = lfirst_node(RangeTblEntry, l); if (rte->perminfoindex != 0) { /* Sanity checks */ /* * Only relation RTEs and subquery RTEs that were once relation * RTEs (views) have their perminfoindex set. */ Assert(rte->rtekind == RTE_RELATION || (rte->rtekind == RTE_SUBQUERY && rte->relkind == RELKIND_VIEW)); (void) getRTEPermissionInfo(rteperminfos, rte); /* Many-to-one mapping not allowed */ Assert(!bms_is_member(rte->perminfoindex, indexset)); indexset = bms_add_member(indexset, rte->perminfoindex); } } /* All rteperminfos are referenced */ Assert(bms_num_members(indexset) == list_length(rteperminfos)); #endif foreach(l, rteperminfos) { RTEPermissionInfo *perminfo = lfirst_node(RTEPermissionInfo, l); Assert(OidIsValid(perminfo->relid)); result = ExecCheckOneRelPerms(perminfo); if (!result) { if (ereport_on_violation) aclcheck_error(ACLCHECK_NO_PRIV, get_relkind_objtype(get_rel_relkind(perminfo->relid)), get_rel_name(perminfo->relid)); return false; } } if (ExecutorCheckPerms_hook) result = (*ExecutorCheckPerms_hook) (rangeTable, rteperminfos, ereport_on_violation); return result; } /* * ExecCheckOneRelPerms * Check access permissions for a single relation. */ static bool ExecCheckOneRelPerms(RTEPermissionInfo *perminfo) { AclMode requiredPerms; AclMode relPerms; AclMode remainingPerms; Oid userid; Oid relOid = perminfo->relid; requiredPerms = perminfo->requiredPerms; Assert(requiredPerms != 0); /* * 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 relation. If that stops being true, we * could call it once in ExecCheckPermissions and pass the userid down * from there. But for now, no need for the extra clutter. */ userid = OidIsValid(perminfo->checkAsUser) ? perminfo->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) { int col = -1; /* * If we lack any permissions that exist only as relation permissions, * we can fail straight away. */ if (remainingPerms & ~(ACL_SELECT | ACL_INSERT | ACL_UPDATE)) return false; /* * 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(perminfo->selectedCols)) { if (pg_attribute_aclcheck_all(relOid, userid, ACL_SELECT, ACLMASK_ANY) != ACLCHECK_OK) return false; } while ((col = bms_next_member(perminfo->selectedCols, col)) >= 0) { /* bit #s are offset by FirstLowInvalidHeapAttributeNumber */ AttrNumber attno = col + FirstLowInvalidHeapAttributeNumber; if (attno == InvalidAttrNumber) { /* Whole-row reference, must have priv on all cols */ if (pg_attribute_aclcheck_all(relOid, userid, ACL_SELECT, ACLMASK_ALL) != ACLCHECK_OK) return false; } else { if (pg_attribute_aclcheck(relOid, attno, userid, ACL_SELECT) != ACLCHECK_OK) return false; } } } /* * Basically the same for the mod columns, for both INSERT and UPDATE * privilege as specified by remainingPerms. */ if (remainingPerms & ACL_INSERT && !ExecCheckPermissionsModified(relOid, userid, perminfo->insertedCols, ACL_INSERT)) return false; if (remainingPerms & ACL_UPDATE && !ExecCheckPermissionsModified(relOid, userid, perminfo->updatedCols, ACL_UPDATE)) return false; } return true; } /* * ExecCheckPermissionsModified * Check INSERT or UPDATE access permissions for a single relation (these * are processed uniformly). */ static bool ExecCheckPermissionsModified(Oid relOid, Oid userid, Bitmapset *modifiedCols, AclMode requiredPerms) { int col = -1; /* * When the query doesn't explicitly update 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 UPDATE. */ if (bms_is_empty(modifiedCols)) { if (pg_attribute_aclcheck_all(relOid, userid, requiredPerms, ACLMASK_ANY) != ACLCHECK_OK) return false; } while ((col = bms_next_member(modifiedCols, col)) >= 0) { /* bit #s are offset by FirstLowInvalidHeapAttributeNumber */ AttrNumber attno = col + FirstLowInvalidHeapAttributeNumber; if (attno == InvalidAttrNumber) { /* whole-row reference can't happen here */ elog(ERROR, "whole-row update is not implemented"); } else { if (pg_attribute_aclcheck(relOid, attno, userid, requiredPerms) != ACLCHECK_OK) return false; } } return true; } /* * Check that the query does not imply any writes to non-temp tables; * unless we're in parallel mode, in which case don't even allow writes * to temp tables. * * Note: in a Hot Standby this would need to reject writes to temp * tables just as we do in parallel mode; but an HS standby can't have created * any temp tables in the first place, so no need to check that. */ static void ExecCheckXactReadOnly(PlannedStmt *plannedstmt) { ListCell *l; /* * Fail if write permissions are requested in parallel mode for table * (temp or non-temp), otherwise fail for any non-temp table. */ foreach(l, plannedstmt->permInfos) { RTEPermissionInfo *perminfo = lfirst_node(RTEPermissionInfo, l); if ((perminfo->requiredPerms & (~ACL_SELECT)) == 0) continue; if (isTempNamespace(get_rel_namespace(perminfo->relid))) continue; PreventCommandIfReadOnly(CreateCommandName((Node *) plannedstmt)); } if (plannedstmt->commandType != CMD_SELECT || plannedstmt->hasModifyingCTE) PreventCommandIfParallelMode(CreateCommandName((Node *) plannedstmt)); } /* ---------------------------------------------------------------- * 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 */ ExecCheckPermissions(rangeTable, plannedstmt->permInfos, true); /* * initialize the node's execution state */ ExecInitRangeTable(estate, rangeTable, plannedstmt->permInfos, bms_copy(plannedstmt->unprunableRelids)); estate->es_plannedstmt = plannedstmt; estate->es_part_prune_infos = plannedstmt->partPruneInfos; /* * Perform runtime "initial" pruning to identify which child subplans, * corresponding to the children of plan nodes that contain * PartitionPruneInfo such as Append, will not be executed. The results, * which are bitmapsets of indexes of the child subplans that will be * executed, are saved in es_part_prune_results. These results correspond * to each PartitionPruneInfo entry, and the es_part_prune_results list is * parallel to es_part_prune_infos. */ ExecDoInitialPruning(estate); /* * Next, build the ExecRowMark array from the PlanRowMark(s), if any. */ if (plannedstmt->rowMarks) { estate->es_rowmarks = (ExecRowMark **) palloc0(estate->es_range_table_size * sizeof(ExecRowMark *)); foreach(l, plannedstmt->rowMarks) { PlanRowMark *rc = (PlanRowMark *) lfirst(l); Oid relid; Relation relation; ExecRowMark *erm; /* * Ignore "parent" rowmarks, because they are irrelevant at * runtime. Also ignore the rowmarks belonging to child tables * that have been pruned in ExecDoInitialPruning(). */ if (rc->isParent || !bms_is_member(rc->rti, estate->es_unpruned_relids)) continue; /* get relation's OID (will produce InvalidOid if subquery) */ relid = exec_rt_fetch(rc->rti, estate)->relid; /* open relation, if we need to access it for this mark type */ switch (rc->markType) { case ROW_MARK_EXCLUSIVE: case ROW_MARK_NOKEYEXCLUSIVE: case ROW_MARK_SHARE: case ROW_MARK_KEYSHARE: case ROW_MARK_REFERENCE: relation = ExecGetRangeTableRelation(estate, rc->rti, false); break; case ROW_MARK_COPY: /* no physical table access is required */ relation = NULL; break; default: elog(ERROR, "unrecognized markType: %d", rc->markType); relation = NULL; /* keep compiler quiet */ break; } /* Check that relation is a legal target for marking */ if (relation) CheckValidRowMarkRel(relation, rc->markType); erm = (ExecRowMark *) palloc(sizeof(ExecRowMark)); erm->relation = relation; erm->relid = relid; erm->rti = rc->rti; erm->prti = rc->prti; erm->rowmarkId = rc->rowmarkId; erm->markType = rc->markType; erm->strength = rc->strength; erm->waitPolicy = rc->waitPolicy; erm->ermActive = false; ItemPointerSetInvalid(&(erm->curCtid)); erm->ermExtra = NULL; Assert(erm->rti > 0 && erm->rti <= estate->es_range_table_size && estate->es_rowmarks[erm->rti - 1] == NULL); estate->es_rowmarks[erm->rti - 1] = erm; } } /* * Initialize the executor's tuple table to empty. */ estate->es_tupleTable = NIL; /* signal that this EState is not used for EPQ */ estate->es_epq_active = NULL; /* * 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_REWIND | EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK); 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. */ 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; TupleTableSlot *slot; slot = ExecInitExtraTupleSlot(estate, NULL, &TTSOpsVirtual); j = ExecInitJunkFilter(planstate->plan->targetlist, slot); estate->es_junkFilter = j; /* Want to return the cleaned tuple type */ tupType = j->jf_cleanTupType; } } queryDesc->tupDesc = tupType; queryDesc->planstate = planstate; } /* * Check that a proposed result relation is a legal target for the operation * * Generally the parser and/or planner should have noticed any such mistake * already, but let's make sure. * * For MERGE, mergeActions is the list of actions that may be performed. The * result relation is required to support every action, regardless of whether * or not they are all executed. * * Note: when changing this function, you probably also need to look at * CheckValidRowMarkRel. */ void CheckValidResultRel(ResultRelInfo *resultRelInfo, CmdType operation, List *mergeActions) { Relation resultRel = resultRelInfo->ri_RelationDesc; FdwRoutine *fdwroutine; /* Expect a fully-formed ResultRelInfo from InitResultRelInfo(). */ Assert(resultRelInfo->ri_needLockTagTuple == IsInplaceUpdateRelation(resultRel)); switch (resultRel->rd_rel->relkind) { case RELKIND_RELATION: case RELKIND_PARTITIONED_TABLE: CheckCmdReplicaIdentity(resultRel, operation); break; case RELKIND_SEQUENCE: ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot change sequence \"%s\"", RelationGetRelationName(resultRel)))); break; case RELKIND_TOASTVALUE: ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot change TOAST relation \"%s\"", RelationGetRelationName(resultRel)))); break; case RELKIND_VIEW: /* * Okay only if there's a suitable INSTEAD OF trigger. Otherwise, * complain, but omit errdetail because we haven't got the * information handy (and given that it really shouldn't happen, * it's not worth great exertion to get). */ if (!view_has_instead_trigger(resultRel, operation, mergeActions)) error_view_not_updatable(resultRel, operation, mergeActions, NULL); break; case RELKIND_MATVIEW: if (!MatViewIncrementalMaintenanceIsEnabled()) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot change materialized view \"%s\"", RelationGetRelationName(resultRel)))); break; case RELKIND_FOREIGN_TABLE: /* Okay only if the FDW supports it */ fdwroutine = resultRelInfo->ri_FdwRoutine; switch (operation) { case CMD_INSERT: if (fdwroutine->ExecForeignInsert == NULL) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot insert into foreign table \"%s\"", RelationGetRelationName(resultRel)))); if (fdwroutine->IsForeignRelUpdatable != NULL && (fdwroutine->IsForeignRelUpdatable(resultRel) & (1 << CMD_INSERT)) == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("foreign table \"%s\" does not allow inserts", RelationGetRelationName(resultRel)))); break; case CMD_UPDATE: if (fdwroutine->ExecForeignUpdate == NULL) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot update foreign table \"%s\"", RelationGetRelationName(resultRel)))); if (fdwroutine->IsForeignRelUpdatable != NULL && (fdwroutine->IsForeignRelUpdatable(resultRel) & (1 << CMD_UPDATE)) == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("foreign table \"%s\" does not allow updates", RelationGetRelationName(resultRel)))); break; case CMD_DELETE: if (fdwroutine->ExecForeignDelete == NULL) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot delete from foreign table \"%s\"", RelationGetRelationName(resultRel)))); if (fdwroutine->IsForeignRelUpdatable != NULL && (fdwroutine->IsForeignRelUpdatable(resultRel) & (1 << CMD_DELETE)) == 0) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("foreign table \"%s\" does not allow deletes", RelationGetRelationName(resultRel)))); break; default: elog(ERROR, "unrecognized CmdType: %d", (int) operation); break; } break; default: ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot change relation \"%s\"", RelationGetRelationName(resultRel)))); break; } } /* * Check that a proposed rowmark target relation is a legal target * * In most cases parser and/or planner should have noticed this already, but * they don't cover all cases. */ static void CheckValidRowMarkRel(Relation rel, RowMarkType markType) { FdwRoutine *fdwroutine; switch (rel->rd_rel->relkind) { case RELKIND_RELATION: case RELKIND_PARTITIONED_TABLE: /* OK */ break; case RELKIND_SEQUENCE: /* Must disallow this because we don't vacuum sequences */ ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot lock rows in sequence \"%s\"", RelationGetRelationName(rel)))); break; case RELKIND_TOASTVALUE: /* We could allow this, but there seems no good reason to */ ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot lock rows in TOAST relation \"%s\"", RelationGetRelationName(rel)))); break; case RELKIND_VIEW: /* Should not get here; planner should have expanded the view */ ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot lock rows in view \"%s\"", RelationGetRelationName(rel)))); break; case RELKIND_MATVIEW: /* Allow referencing a matview, but not actual locking clauses */ if (markType != ROW_MARK_REFERENCE) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot lock rows in materialized view \"%s\"", RelationGetRelationName(rel)))); break; case RELKIND_FOREIGN_TABLE: /* Okay only if the FDW supports it */ fdwroutine = GetFdwRoutineForRelation(rel, false); if (fdwroutine->RefetchForeignRow == NULL) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot lock rows in foreign table \"%s\"", RelationGetRelationName(rel)))); break; default: ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("cannot lock rows in relation \"%s\"", RelationGetRelationName(rel)))); break; } } /* * Initialize ResultRelInfo data for one result relation * * Caution: before Postgres 9.1, this function included the relkind checking * that's now in CheckValidResultRel, and it also did ExecOpenIndices if * appropriate. Be sure callers cover those needs. */ void InitResultRelInfo(ResultRelInfo *resultRelInfo, Relation resultRelationDesc, Index resultRelationIndex, ResultRelInfo *partition_root_rri, int instrument_options) { 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; resultRelInfo->ri_needLockTagTuple = IsInplaceUpdateRelation(resultRelationDesc); /* 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)); resultRelInfo->ri_TrigWhenExprs = (ExprState **) palloc0(n * sizeof(ExprState *)); if (instrument_options) resultRelInfo->ri_TrigInstrument = InstrAlloc(n, instrument_options, false); } else { resultRelInfo->ri_TrigFunctions = NULL; resultRelInfo->ri_TrigWhenExprs = NULL; resultRelInfo->ri_TrigInstrument = NULL; } if (resultRelationDesc->rd_rel->relkind == RELKIND_FOREIGN_TABLE) resultRelInfo->ri_FdwRoutine = GetFdwRoutineForRelation(resultRelationDesc, true); else resultRelInfo->ri_FdwRoutine = NULL; /* The following fields are set later if needed */ resultRelInfo->ri_RowIdAttNo = 0; resultRelInfo->ri_extraUpdatedCols = NULL; resultRelInfo->ri_projectNew = NULL; resultRelInfo->ri_newTupleSlot = NULL; resultRelInfo->ri_oldTupleSlot = NULL; resultRelInfo->ri_projectNewInfoValid = false; resultRelInfo->ri_FdwState = NULL; resultRelInfo->ri_usesFdwDirectModify = false; resultRelInfo->ri_CheckConstraintExprs = NULL; resultRelInfo->ri_GenVirtualNotNullConstraintExprs = NULL; resultRelInfo->ri_GeneratedExprsI = NULL; resultRelInfo->ri_GeneratedExprsU = NULL; resultRelInfo->ri_projectReturning = NULL; resultRelInfo->ri_onConflictArbiterIndexes = NIL; resultRelInfo->ri_onConflict = NULL; resultRelInfo->ri_ReturningSlot = NULL; resultRelInfo->ri_TrigOldSlot = NULL; resultRelInfo->ri_TrigNewSlot = NULL; resultRelInfo->ri_AllNullSlot = NULL; resultRelInfo->ri_MergeActions[MERGE_WHEN_MATCHED] = NIL; resultRelInfo->ri_MergeActions[MERGE_WHEN_NOT_MATCHED_BY_SOURCE] = NIL; resultRelInfo->ri_MergeActions[MERGE_WHEN_NOT_MATCHED_BY_TARGET] = NIL; resultRelInfo->ri_MergeJoinCondition = NULL; /* * Only ExecInitPartitionInfo() and ExecInitPartitionDispatchInfo() pass * non-NULL partition_root_rri. For child relations that are part of the * initial query rather than being dynamically added by tuple routing, * this field is filled in ExecInitModifyTable(). */ resultRelInfo->ri_RootResultRelInfo = partition_root_rri; /* Set by ExecGetRootToChildMap */ resultRelInfo->ri_RootToChildMap = NULL; resultRelInfo->ri_RootToChildMapValid = false; /* Set by ExecInitRoutingInfo */ resultRelInfo->ri_PartitionTupleSlot = NULL; resultRelInfo->ri_ChildToRootMap = NULL; resultRelInfo->ri_ChildToRootMapValid = false; resultRelInfo->ri_CopyMultiInsertBuffer = NULL; } /* * 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, * or the es_tuple_routing_result_relations list (if any). (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 *rootRelInfo) { ResultRelInfo *rInfo; ListCell *l; Relation rel; MemoryContext oldcontext; /* Search through the query result relations */ foreach(l, estate->es_opened_result_relations) { rInfo = lfirst(l); if (RelationGetRelid(rInfo->ri_RelationDesc) == relid) return rInfo; } /* * Search through the result relations that were created during tuple * routing, if any. */ foreach(l, estate->es_tuple_routing_result_relations) { rInfo = (ResultRelInfo *) lfirst(l); if (RelationGetRelid(rInfo->ri_RelationDesc) == relid) return rInfo; } /* 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. Also, we need not * recheck the relkind, so no need for CheckValidResultRel. */ rel = table_open(relid, NoLock); /* * Make the new entry in the right context. */ oldcontext = MemoryContextSwitchTo(estate->es_query_cxt); rInfo = makeNode(ResultRelInfo); InitResultRelInfo(rInfo, rel, 0, /* dummy rangetable index */ rootRelInfo, estate->es_instrument); estate->es_trig_target_relations = lappend(estate->es_trig_target_relations, rInfo); MemoryContextSwitchTo(oldcontext); /* * Currently, we don't need any index information in ResultRelInfos used * only for triggers, so no need to call ExecOpenIndices. */ return rInfo; } /* * Return the ancestor relations of a given leaf partition result relation * up to and including the query's root target relation. * * These work much like the ones opened by ExecGetTriggerResultRel, except * that we need to keep them in a separate list. * * These are closed by ExecCloseResultRelations. */ List * ExecGetAncestorResultRels(EState *estate, ResultRelInfo *resultRelInfo) { ResultRelInfo *rootRelInfo = resultRelInfo->ri_RootResultRelInfo; Relation partRel = resultRelInfo->ri_RelationDesc; Oid rootRelOid; if (!partRel->rd_rel->relispartition) elog(ERROR, "cannot find ancestors of a non-partition result relation"); Assert(rootRelInfo != NULL); rootRelOid = RelationGetRelid(rootRelInfo->ri_RelationDesc); if (resultRelInfo->ri_ancestorResultRels == NIL) { ListCell *lc; List *oids = get_partition_ancestors(RelationGetRelid(partRel)); List *ancResultRels = NIL; foreach(lc, oids) { Oid ancOid = lfirst_oid(lc); Relation ancRel; ResultRelInfo *rInfo; /* * Ignore the root ancestor here, and use ri_RootResultRelInfo * (below) for it instead. Also, we stop climbing up the * hierarchy when we find the table that was mentioned in the * query. */ if (ancOid == rootRelOid) break; /* * All ancestors up to the root target relation must have been * locked by the planner or AcquireExecutorLocks(). */ ancRel = table_open(ancOid, NoLock); rInfo = makeNode(ResultRelInfo); /* dummy rangetable index */ InitResultRelInfo(rInfo, ancRel, 0, NULL, estate->es_instrument); ancResultRels = lappend(ancResultRels, rInfo); } ancResultRels = lappend(ancResultRels, rootRelInfo); resultRelInfo->ri_ancestorResultRels = ancResultRels; } /* We must have found some ancestor */ Assert(resultRelInfo->ri_ancestorResultRels != NIL); return resultRelInfo->ri_ancestorResultRels; } /* ---------------------------------------------------------------- * ExecPostprocessPlan * * Give plan nodes a final chance to execute before shutdown * ---------------------------------------------------------------- */ static void ExecPostprocessPlan(EState *estate) { ListCell *lc; /* * Make sure nodes run forward. */ estate->es_direction = ForwardScanDirection; /* * Run any secondary ModifyTable nodes to completion, in case the main * query did not fetch all rows from them. (We do this to ensure that * such nodes have predictable results.) */ foreach(lc, estate->es_auxmodifytables) { PlanState *ps = (PlanState *) lfirst(lc); for (;;) { TupleTableSlot *slot; /* Reset the per-output-tuple exprcontext each time */ ResetPerTupleExprContext(estate); slot = ExecProcNode(ps); if (TupIsNull(slot)) break; } } } /* ---------------------------------------------------------------- * 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) { ListCell *l; /* * 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 any Relations that have been opened for range table entries or * result relations. */ ExecCloseResultRelations(estate); ExecCloseRangeTableRelations(estate); } /* * Close any relations that have been opened for ResultRelInfos. */ void ExecCloseResultRelations(EState *estate) { ListCell *l; /* * close indexes of result relation(s) if any. (Rels themselves are * closed in ExecCloseRangeTableRelations()) * * In addition, close the stub RTs that may be in each resultrel's * ri_ancestorResultRels. */ foreach(l, estate->es_opened_result_relations) { ResultRelInfo *resultRelInfo = lfirst(l); ListCell *lc; ExecCloseIndices(resultRelInfo); foreach(lc, resultRelInfo->ri_ancestorResultRels) { ResultRelInfo *rInfo = lfirst(lc); /* * Ancestors with RTI > 0 (should only be the root ancestor) are * closed by ExecCloseRangeTableRelations. */ if (rInfo->ri_RangeTableIndex > 0) continue; table_close(rInfo->ri_RelationDesc, NoLock); } } /* Close any relations that have been opened by ExecGetTriggerResultRel(). */ foreach(l, estate->es_trig_target_relations) { ResultRelInfo *resultRelInfo = (ResultRelInfo *) lfirst(l); /* * Assert this is a "dummy" ResultRelInfo, see above. Otherwise we * might be issuing a duplicate close against a Relation opened by * ExecGetRangeTableRelation. */ Assert(resultRelInfo->ri_RangeTableIndex == 0); /* * Since ExecGetTriggerResultRel doesn't call ExecOpenIndices for * these rels, we needn't call ExecCloseIndices either. */ Assert(resultRelInfo->ri_NumIndices == 0); table_close(resultRelInfo->ri_RelationDesc, NoLock); } } /* * Close all relations opened by ExecGetRangeTableRelation(). * * We do not release any locks we might hold on those rels. */ void ExecCloseRangeTableRelations(EState *estate) { int i; for (i = 0; i < estate->es_range_table_size; i++) { if (estate->es_relations[i]) table_close(estate->es_relations[i], NoLock); } } /* ---------------------------------------------------------------- * ExecutePlan * * Processes the query plan until we have retrieved 'numberTuples' tuples, * moving in the specified direction. * * Runs to completion if numberTuples is 0 * ---------------------------------------------------------------- */ static void ExecutePlan(QueryDesc *queryDesc, CmdType operation, bool sendTuples, uint64 numberTuples, ScanDirection direction, DestReceiver *dest) { EState *estate = queryDesc->estate; PlanState *planstate = queryDesc->planstate; bool use_parallel_mode; TupleTableSlot *slot; uint64 current_tuple_count; /* * initialize local variables */ current_tuple_count = 0; /* * Set the direction. */ estate->es_direction = direction; /* * Set up parallel mode if appropriate. * * Parallel mode only supports complete execution of a plan. If we've * already partially executed it, or if the caller asks us to exit early, * we must force the plan to run without parallelism. */ if (queryDesc->already_executed || numberTuples != 0) use_parallel_mode = false; else use_parallel_mode = queryDesc->plannedstmt->parallelModeNeeded; queryDesc->already_executed = true; estate->es_use_parallel_mode = use_parallel_mode; if (use_parallel_mode) EnterParallelMode(); /* * 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 */ slot = ExecProcNode(planstate); /* * if the tuple is null, then we assume there is nothing more to * process so we just end the loop... */ if (TupIsNull(slot)) break; /* * 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.) */ if (estate->es_junkFilter != NULL) slot = ExecFilterJunk(estate->es_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) { /* * If we are not able to send the tuple, we assume the destination * has closed and no more tuples can be sent. If that's the case, * end the loop. */ if (!dest->receiveSlot(slot, dest)) break; } /* * 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; } /* * If we know we won't need to back up, we can release resources at this * point. */ if (!(estate->es_top_eflags & EXEC_FLAG_BACKWARD)) ExecShutdownNode(planstate); if (use_parallel_mode) ExitParallelMode(); } /* * ExecRelCheck --- check that tuple meets check constraints for result relation * * Returns NULL if OK, else name of failed check constraint */ 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; /* * CheckNNConstraintFetch let this pass with only a warning, but now we * should fail rather than possibly failing to enforce an important * constraint. */ if (ncheck != rel->rd_rel->relchecks) elog(ERROR, "%d pg_constraint record(s) missing for relation \"%s\"", rel->rd_rel->relchecks - ncheck, RelationGetRelationName(rel)); /* * 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_CheckConstraintExprs == NULL) { oldContext = MemoryContextSwitchTo(estate->es_query_cxt); resultRelInfo->ri_CheckConstraintExprs = palloc0_array(ExprState *, ncheck); for (int i = 0; i < ncheck; i++) { Expr *checkconstr; /* Skip not enforced constraint */ if (!check[i].ccenforced) continue; checkconstr = stringToNode(check[i].ccbin); checkconstr = (Expr *) expand_generated_columns_in_expr((Node *) checkconstr, rel, 1); resultRelInfo->ri_CheckConstraintExprs[i] = ExecPrepareExpr(checkconstr, 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 (int i = 0; i < ncheck; i++) { ExprState *checkconstr = resultRelInfo->ri_CheckConstraintExprs[i]; /* * NOTE: SQL specifies that a NULL result from a constraint expression * is not to be treated as a failure. Therefore, use ExecCheck not * ExecQual. */ if (checkconstr && !ExecCheck(checkconstr, econtext)) return check[i].ccname; } /* NULL result means no error */ return NULL; } /* * ExecPartitionCheck --- check that tuple meets the partition constraint. * * Returns true if it meets the partition constraint. If the constraint * fails and we're asked to emit an error, do so and don't return; otherwise * return false. */ bool ExecPartitionCheck(ResultRelInfo *resultRelInfo, TupleTableSlot *slot, EState *estate, bool emitError) { ExprContext *econtext; bool success; /* * If first time through, build expression state tree for the partition * check expression. (In the corner case where the partition check * expression is empty, ie there's a default partition and nothing else, * we'll be fooled into executing this code each time through. But it's * pretty darn cheap in that case, so we don't worry about it.) */ if (resultRelInfo->ri_PartitionCheckExpr == NULL) { /* * Ensure that the qual tree and prepared expression are in the * query-lifespan context. */ MemoryContext oldcxt = MemoryContextSwitchTo(estate->es_query_cxt); List *qual = RelationGetPartitionQual(resultRelInfo->ri_RelationDesc); resultRelInfo->ri_PartitionCheckExpr = ExecPrepareCheck(qual, estate); MemoryContextSwitchTo(oldcxt); } /* * 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; /* * As in case of the cataloged constraints, we treat a NULL result as * success here, not a failure. */ success = ExecCheck(resultRelInfo->ri_PartitionCheckExpr, econtext); /* if asked to emit error, don't actually return on failure */ if (!success && emitError) ExecPartitionCheckEmitError(resultRelInfo, slot, estate); return success; } /* * ExecPartitionCheckEmitError - Form and emit an error message after a failed * partition constraint check. */ void ExecPartitionCheckEmitError(ResultRelInfo *resultRelInfo, TupleTableSlot *slot, EState *estate) { Oid root_relid; TupleDesc tupdesc; char *val_desc; Bitmapset *modifiedCols; /* * If the tuple has been routed, it's been converted to the partition's * rowtype, which might differ from the root table's. We must convert it * back to the root table's rowtype so that val_desc in the error message * matches the input tuple. */ if (resultRelInfo->ri_RootResultRelInfo) { ResultRelInfo *rootrel = resultRelInfo->ri_RootResultRelInfo; TupleDesc old_tupdesc; AttrMap *map; root_relid = RelationGetRelid(rootrel->ri_RelationDesc); tupdesc = RelationGetDescr(rootrel->ri_RelationDesc); old_tupdesc = RelationGetDescr(resultRelInfo->ri_RelationDesc); /* a reverse map */ map = build_attrmap_by_name_if_req(old_tupdesc, tupdesc, false); /* * Partition-specific slot's tupdesc can't be changed, so allocate a * new one. */ if (map != NULL) slot = execute_attr_map_slot(map, slot, MakeTupleTableSlot(tupdesc, &TTSOpsVirtual)); modifiedCols = bms_union(ExecGetInsertedCols(rootrel, estate), ExecGetUpdatedCols(rootrel, estate)); } else { root_relid = RelationGetRelid(resultRelInfo->ri_RelationDesc); tupdesc = RelationGetDescr(resultRelInfo->ri_RelationDesc); modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate), ExecGetUpdatedCols(resultRelInfo, estate)); } val_desc = ExecBuildSlotValueDescription(root_relid, slot, tupdesc, modifiedCols, 64); ereport(ERROR, (errcode(ERRCODE_CHECK_VIOLATION), errmsg("new row for relation \"%s\" violates partition constraint", RelationGetRelationName(resultRelInfo->ri_RelationDesc)), val_desc ? errdetail("Failing row contains %s.", val_desc) : 0, errtable(resultRelInfo->ri_RelationDesc))); } /* * ExecConstraints - check constraints of the tuple in 'slot' * * This checks the traditional NOT NULL and check constraints. * * The partition constraint is *NOT* checked. * * Note: 'slot' contains the tuple to check the constraints of, which may * have been converted from the original input tuple after tuple routing. * 'resultRelInfo' is the final result relation, after tuple routing. */ void ExecConstraints(ResultRelInfo *resultRelInfo, TupleTableSlot *slot, EState *estate) { Relation rel = resultRelInfo->ri_RelationDesc; TupleDesc tupdesc = RelationGetDescr(rel); TupleConstr *constr = tupdesc->constr; Bitmapset *modifiedCols; List *notnull_virtual_attrs = NIL; Assert(constr); /* we should not be called otherwise */ /* * Verify not-null constraints. * * Not-null constraints on virtual generated columns are collected and * checked separately below. */ if (constr->has_not_null) { for (AttrNumber attnum = 1; attnum <= tupdesc->natts; attnum++) { Form_pg_attribute att = TupleDescAttr(tupdesc, attnum - 1); if (att->attnotnull && att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL) notnull_virtual_attrs = lappend_int(notnull_virtual_attrs, attnum); else if (att->attnotnull && slot_attisnull(slot, attnum)) ReportNotNullViolationError(resultRelInfo, slot, estate, attnum); } } /* * Verify not-null constraints on virtual generated column, if any. */ if (notnull_virtual_attrs) { AttrNumber attnum; attnum = ExecRelGenVirtualNotNull(resultRelInfo, slot, estate, notnull_virtual_attrs); if (attnum != InvalidAttrNumber) ReportNotNullViolationError(resultRelInfo, slot, estate, attnum); } /* * Verify check constraints. */ if (rel->rd_rel->relchecks > 0) { const char *failed; if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL) { char *val_desc; Relation orig_rel = rel; /* * If the tuple has been routed, it's been converted to the * partition's rowtype, which might differ from the root table's. * We must convert it back to the root table's rowtype so that * val_desc shown error message matches the input tuple. */ if (resultRelInfo->ri_RootResultRelInfo) { ResultRelInfo *rootrel = resultRelInfo->ri_RootResultRelInfo; TupleDesc old_tupdesc = RelationGetDescr(rel); AttrMap *map; tupdesc = RelationGetDescr(rootrel->ri_RelationDesc); /* a reverse map */ map = build_attrmap_by_name_if_req(old_tupdesc, tupdesc, false); /* * Partition-specific slot's tupdesc can't be changed, so * allocate a new one. */ if (map != NULL) slot = execute_attr_map_slot(map, slot, MakeTupleTableSlot(tupdesc, &TTSOpsVirtual)); modifiedCols = bms_union(ExecGetInsertedCols(rootrel, estate), ExecGetUpdatedCols(rootrel, estate)); rel = rootrel->ri_RelationDesc; } else modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate), ExecGetUpdatedCols(resultRelInfo, estate)); val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel), slot, tupdesc, modifiedCols, 64); ereport(ERROR, (errcode(ERRCODE_CHECK_VIOLATION), errmsg("new row for relation \"%s\" violates check constraint \"%s\"", RelationGetRelationName(orig_rel), failed), val_desc ? errdetail("Failing row contains %s.", val_desc) : 0, errtableconstraint(orig_rel, failed))); } } } /* * Verify not-null constraints on virtual generated columns of the given * tuple slot. * * Return value of InvalidAttrNumber means all not-null constraints on virtual * generated columns are satisfied. A return value > 0 means a not-null * violation happened for that attribute. * * notnull_virtual_attrs is the list of the attnums of virtual generated column with * not-null constraints. */ AttrNumber ExecRelGenVirtualNotNull(ResultRelInfo *resultRelInfo, TupleTableSlot *slot, EState *estate, List *notnull_virtual_attrs) { Relation rel = resultRelInfo->ri_RelationDesc; ExprContext *econtext; MemoryContext oldContext; /* * We implement this by building a NullTest node for each virtual * generated column, which we cache in resultRelInfo, and running those * through ExecCheck(). */ if (resultRelInfo->ri_GenVirtualNotNullConstraintExprs == NULL) { oldContext = MemoryContextSwitchTo(estate->es_query_cxt); resultRelInfo->ri_GenVirtualNotNullConstraintExprs = palloc0_array(ExprState *, list_length(notnull_virtual_attrs)); foreach_int(attnum, notnull_virtual_attrs) { int i = foreach_current_index(attnum); NullTest *nnulltest; /* "generated_expression IS NOT NULL" check. */ nnulltest = makeNode(NullTest); nnulltest->arg = (Expr *) build_generation_expression(rel, attnum); nnulltest->nulltesttype = IS_NOT_NULL; nnulltest->argisrow = false; nnulltest->location = -1; resultRelInfo->ri_GenVirtualNotNullConstraintExprs[i] = ExecPrepareExpr((Expr *) nnulltest, estate); } MemoryContextSwitchTo(oldContext); } /* * We will use the EState's per-tuple context for evaluating virtual * generated column not null 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 check constraints for virtual generated column */ foreach_int(attnum, notnull_virtual_attrs) { int i = foreach_current_index(attnum); ExprState *exprstate = resultRelInfo->ri_GenVirtualNotNullConstraintExprs[i]; Assert(exprstate != NULL); if (!ExecCheck(exprstate, econtext)) return attnum; } /* InvalidAttrNumber result means no error */ return InvalidAttrNumber; } /* * Report a violation of a not-null constraint that was already detected. */ static void ReportNotNullViolationError(ResultRelInfo *resultRelInfo, TupleTableSlot *slot, EState *estate, int attnum) { Bitmapset *modifiedCols; char *val_desc; Relation rel = resultRelInfo->ri_RelationDesc; Relation orig_rel = rel; TupleDesc tupdesc = RelationGetDescr(rel); TupleDesc orig_tupdesc = RelationGetDescr(rel); Form_pg_attribute att = TupleDescAttr(tupdesc, attnum - 1); Assert(attnum > 0); /* * If the tuple has been routed, it's been converted to the partition's * rowtype, which might differ from the root table's. We must convert it * back to the root table's rowtype so that val_desc shown error message * matches the input tuple. */ if (resultRelInfo->ri_RootResultRelInfo) { ResultRelInfo *rootrel = resultRelInfo->ri_RootResultRelInfo; AttrMap *map; tupdesc = RelationGetDescr(rootrel->ri_RelationDesc); /* a reverse map */ map = build_attrmap_by_name_if_req(orig_tupdesc, tupdesc, false); /* * Partition-specific slot's tupdesc can't be changed, so allocate a * new one. */ if (map != NULL) slot = execute_attr_map_slot(map, slot, MakeTupleTableSlot(tupdesc, &TTSOpsVirtual)); modifiedCols = bms_union(ExecGetInsertedCols(rootrel, estate), ExecGetUpdatedCols(rootrel, estate)); rel = rootrel->ri_RelationDesc; } else modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate), ExecGetUpdatedCols(resultRelInfo, estate)); val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel), slot, tupdesc, modifiedCols, 64); ereport(ERROR, errcode(ERRCODE_NOT_NULL_VIOLATION), errmsg("null value in column \"%s\" of relation \"%s\" violates not-null constraint", NameStr(att->attname), RelationGetRelationName(orig_rel)), val_desc ? errdetail("Failing row contains %s.", val_desc) : 0, errtablecol(orig_rel, attnum)); } /* * ExecWithCheckOptions -- check that tuple satisfies any WITH CHECK OPTIONs * of the specified kind. * * Note that this needs to be called multiple times to ensure that all kinds of * WITH CHECK OPTIONs are handled (both those from views which have the WITH * CHECK OPTION set and from row-level security policies). See ExecInsert() * and ExecUpdate(). */ void ExecWithCheckOptions(WCOKind kind, ResultRelInfo *resultRelInfo, TupleTableSlot *slot, EState *estate) { Relation rel = resultRelInfo->ri_RelationDesc; TupleDesc tupdesc = RelationGetDescr(rel); ExprContext *econtext; ListCell *l1, *l2; /* * 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; /* Check each of the constraints */ forboth(l1, resultRelInfo->ri_WithCheckOptions, l2, resultRelInfo->ri_WithCheckOptionExprs) { WithCheckOption *wco = (WithCheckOption *) lfirst(l1); ExprState *wcoExpr = (ExprState *) lfirst(l2); /* * Skip any WCOs which are not the kind we are looking for at this * time. */ if (wco->kind != kind) continue; /* * WITH CHECK OPTION checks are intended to ensure that the new tuple * is visible (in the case of a view) or that it passes the * 'with-check' policy (in the case of row security). If the qual * evaluates to NULL or FALSE, then the new tuple won't be included in * the view or doesn't pass the 'with-check' policy for the table. */ if (!ExecQual(wcoExpr, econtext)) { char *val_desc; Bitmapset *modifiedCols; switch (wco->kind) { /* * For WITH CHECK OPTIONs coming from views, we might be * able to provide the details on the row, depending on * the permissions on the relation (that is, if the user * could view it directly anyway). For RLS violations, we * don't include the data since we don't know if the user * should be able to view the tuple as that depends on the * USING policy. */ case WCO_VIEW_CHECK: /* See the comment in ExecConstraints(). */ if (resultRelInfo->ri_RootResultRelInfo) { ResultRelInfo *rootrel = resultRelInfo->ri_RootResultRelInfo; TupleDesc old_tupdesc = RelationGetDescr(rel); AttrMap *map; tupdesc = RelationGetDescr(rootrel->ri_RelationDesc); /* a reverse map */ map = build_attrmap_by_name_if_req(old_tupdesc, tupdesc, false); /* * Partition-specific slot's tupdesc can't be changed, * so allocate a new one. */ if (map != NULL) slot = execute_attr_map_slot(map, slot, MakeTupleTableSlot(tupdesc, &TTSOpsVirtual)); modifiedCols = bms_union(ExecGetInsertedCols(rootrel, estate), ExecGetUpdatedCols(rootrel, estate)); rel = rootrel->ri_RelationDesc; } else modifiedCols = bms_union(ExecGetInsertedCols(resultRelInfo, estate), ExecGetUpdatedCols(resultRelInfo, estate)); val_desc = ExecBuildSlotValueDescription(RelationGetRelid(rel), slot, tupdesc, modifiedCols, 64); ereport(ERROR, (errcode(ERRCODE_WITH_CHECK_OPTION_VIOLATION), errmsg("new row violates check option for view \"%s\"", wco->relname), val_desc ? errdetail("Failing row contains %s.", val_desc) : 0)); break; case WCO_RLS_INSERT_CHECK: case WCO_RLS_UPDATE_CHECK: if (wco->polname != NULL) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("new row violates row-level security policy \"%s\" for table \"%s\"", wco->polname, wco->relname))); else ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("new row violates row-level security policy for table \"%s\"", wco->relname))); break; case WCO_RLS_MERGE_UPDATE_CHECK: case WCO_RLS_MERGE_DELETE_CHECK: if (wco->polname != NULL) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("target row violates row-level security policy \"%s\" (USING expression) for table \"%s\"", wco->polname, wco->relname))); else ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("target row violates row-level security policy (USING expression) for table \"%s\"", wco->relname))); break; case WCO_RLS_CONFLICT_CHECK: if (wco->polname != NULL) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("new row violates row-level security policy \"%s\" (USING expression) for table \"%s\"", wco->polname, wco->relname))); else ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("new row violates row-level security policy (USING expression) for table \"%s\"", wco->relname))); break; default: elog(ERROR, "unrecognized WCO kind: %u", wco->kind); break; } } } } /* * ExecBuildSlotValueDescription -- construct a string representing a tuple * * This is intentionally very similar to BuildIndexValueDescription, but * unlike that function, we truncate long field values (to at most maxfieldlen * bytes). That seems necessary here since heap field values could be very * long, whereas index entries typically aren't so wide. * * Also, unlike the case with index entries, we need to be prepared to ignore * dropped columns. We used to use the slot's tuple descriptor to decode the * data, but the slot's descriptor doesn't identify dropped columns, so we * now need to be passed the relation's descriptor. * * Note that, like BuildIndexValueDescription, if the user does not have * permission to view any of the columns involved, a NULL is returned. Unlike * BuildIndexValueDescription, if the user has access to view a subset of the * column involved, that subset will be returned with a key identifying which * columns they are. */ char * ExecBuildSlotValueDescription(Oid reloid, TupleTableSlot *slot, TupleDesc tupdesc, Bitmapset *modifiedCols, int maxfieldlen) { StringInfoData buf; StringInfoData collist; bool write_comma = false; bool write_comma_collist = false; int i; AclResult aclresult; bool table_perm = false; bool any_perm = false; /* * Check if RLS is enabled and should be active for the relation; if so, * then don't return anything. Otherwise, go through normal permission * checks. */ if (check_enable_rls(reloid, InvalidOid, true) == RLS_ENABLED) return NULL; initStringInfo(&buf); appendStringInfoChar(&buf, '('); /* * Check if the user has permissions to see the row. Table-level SELECT * allows access to all columns. If the user does not have table-level * SELECT then we check each column and include those the user has SELECT * rights on. Additionally, we always include columns the user provided * data for. */ aclresult = pg_class_aclcheck(reloid, GetUserId(), ACL_SELECT); if (aclresult != ACLCHECK_OK) { /* Set up the buffer for the column list */ initStringInfo(&collist); appendStringInfoChar(&collist, '('); } else table_perm = any_perm = true; /* Make sure the tuple is fully deconstructed */ slot_getallattrs(slot); for (i = 0; i < tupdesc->natts; i++) { bool column_perm = false; char *val; int vallen; Form_pg_attribute att = TupleDescAttr(tupdesc, i); /* ignore dropped columns */ if (att->attisdropped) continue; if (!table_perm) { /* * No table-level SELECT, so need to make sure they either have * SELECT rights on the column or that they have provided the data * for the column. If not, omit this column from the error * message. */ aclresult = pg_attribute_aclcheck(reloid, att->attnum, GetUserId(), ACL_SELECT); if (bms_is_member(att->attnum - FirstLowInvalidHeapAttributeNumber, modifiedCols) || aclresult == ACLCHECK_OK) { column_perm = any_perm = true; if (write_comma_collist) appendStringInfoString(&collist, ", "); else write_comma_collist = true; appendStringInfoString(&collist, NameStr(att->attname)); } } if (table_perm || column_perm) { if (att->attgenerated == ATTRIBUTE_GENERATED_VIRTUAL) val = "virtual"; else if (slot->tts_isnull[i]) val = "null"; else { Oid foutoid; bool typisvarlena; getTypeOutputInfo(att->atttypid, &foutoid, &typisvarlena); val = OidOutputFunctionCall(foutoid, slot->tts_values[i]); } if (write_comma) appendStringInfoString(&buf, ", "); else write_comma = true; /* truncate if needed */ vallen = strlen(val); if (vallen <= maxfieldlen) appendBinaryStringInfo(&buf, val, vallen); else { vallen = pg_mbcliplen(val, vallen, maxfieldlen); appendBinaryStringInfo(&buf, val, vallen); appendStringInfoString(&buf, "..."); } } } /* If we end up with zero columns being returned, then return NULL. */ if (!any_perm) return NULL; appendStringInfoChar(&buf, ')'); if (!table_perm) { appendStringInfoString(&collist, ") = "); appendBinaryStringInfo(&collist, buf.data, buf.len); return collist.data; } return buf.data; } /* * ExecUpdateLockMode -- find the appropriate UPDATE tuple lock mode for a * given ResultRelInfo */ LockTupleMode ExecUpdateLockMode(EState *estate, ResultRelInfo *relinfo) { Bitmapset *keyCols; Bitmapset *updatedCols; /* * Compute lock mode to use. If columns that are part of the key have not * been modified, then we can use a weaker lock, allowing for better * concurrency. */ updatedCols = ExecGetAllUpdatedCols(relinfo, estate); keyCols = RelationGetIndexAttrBitmap(relinfo->ri_RelationDesc, INDEX_ATTR_BITMAP_KEY); if (bms_overlap(keyCols, updatedCols)) return LockTupleExclusive; return LockTupleNoKeyExclusive; } /* * ExecFindRowMark -- find the ExecRowMark struct for given rangetable index * * If no such struct, either return NULL or throw error depending on missing_ok */ ExecRowMark * ExecFindRowMark(EState *estate, Index rti, bool missing_ok) { if (rti > 0 && rti <= estate->es_range_table_size && estate->es_rowmarks != NULL) { ExecRowMark *erm = estate->es_rowmarks[rti - 1]; if (erm) return erm; } if (!missing_ok) elog(ERROR, "failed to find ExecRowMark for rangetable index %u", rti); return NULL; } /* * ExecBuildAuxRowMark -- create an ExecAuxRowMark struct * * Inputs are the underlying ExecRowMark struct and the targetlist of the * input plan node (not planstate node!). We need the latter to find out * the column numbers of the resjunk columns. */ ExecAuxRowMark * ExecBuildAuxRowMark(ExecRowMark *erm, List *targetlist) { ExecAuxRowMark *aerm = (ExecAuxRowMark *) palloc0(sizeof(ExecAuxRowMark)); char resname[32]; aerm->rowmark = erm; /* Look up the resjunk columns associated with this rowmark */ if (erm->markType != ROW_MARK_COPY) { /* need ctid for all methods other than COPY */ snprintf(resname, sizeof(resname), "ctid%u", erm->rowmarkId); aerm->ctidAttNo = ExecFindJunkAttributeInTlist(targetlist, resname); if (!AttributeNumberIsValid(aerm->ctidAttNo)) elog(ERROR, "could not find junk %s column", resname); } else { /* need wholerow if COPY */ snprintf(resname, sizeof(resname), "wholerow%u", erm->rowmarkId); aerm->wholeAttNo = ExecFindJunkAttributeInTlist(targetlist, resname); if (!AttributeNumberIsValid(aerm->wholeAttNo)) elog(ERROR, "could not find junk %s column", resname); } /* if child rel, need tableoid */ if (erm->rti != erm->prti) { snprintf(resname, sizeof(resname), "tableoid%u", erm->rowmarkId); aerm->toidAttNo = ExecFindJunkAttributeInTlist(targetlist, resname); if (!AttributeNumberIsValid(aerm->toidAttNo)) elog(ERROR, "could not find junk %s column", resname); } return aerm; } /* * EvalPlanQual logic --- recheck modified tuple(s) to see if we want to * process the updated version under READ COMMITTED rules. * * See backend/executor/README for some info about how this works. */ /* * Check the updated version of a tuple to see if we want to process it under * READ COMMITTED rules. * * epqstate - state for EvalPlanQual rechecking * relation - table containing tuple * rti - rangetable index of table containing tuple * inputslot - tuple for processing - this can be the slot from * EvalPlanQualSlot() for this rel, for increased efficiency. * * This tests whether the tuple in inputslot still matches the relevant * quals. For that result to be useful, typically the input tuple has to be * last row version (otherwise the result isn't particularly useful) and * locked (otherwise the result might be out of date). That's typically * achieved by using table_tuple_lock() with the * TUPLE_LOCK_FLAG_FIND_LAST_VERSION flag. * * Returns a slot containing the new candidate update/delete tuple, or * NULL if we determine we shouldn't process the row. */ TupleTableSlot * EvalPlanQual(EPQState *epqstate, Relation relation, Index rti, TupleTableSlot *inputslot) { TupleTableSlot *slot; TupleTableSlot *testslot; Assert(rti > 0); /* * Need to run a recheck subquery. Initialize or reinitialize EPQ state. */ EvalPlanQualBegin(epqstate); /* * Callers will often use the EvalPlanQualSlot to store the tuple to avoid * an unnecessary copy. */ testslot = EvalPlanQualSlot(epqstate, relation, rti); if (testslot != inputslot) ExecCopySlot(testslot, inputslot); /* * Mark that an EPQ tuple is available for this relation. (If there is * more than one result relation, the others remain marked as having no * tuple available.) */ epqstate->relsubs_done[rti - 1] = false; epqstate->relsubs_blocked[rti - 1] = false; /* * Run the EPQ query. We assume it will return at most one tuple. */ slot = EvalPlanQualNext(epqstate); /* * If we got a tuple, force the slot to materialize the tuple so that it * is not dependent on any local state in the EPQ query (in particular, * it's highly likely that the slot contains references to any pass-by-ref * datums that may be present in copyTuple). As with the next step, this * is to guard against early re-use of the EPQ query. */ if (!TupIsNull(slot)) ExecMaterializeSlot(slot); /* * Clear out the test tuple, and mark that no tuple is available here. * This is needed in case the EPQ state is re-used to test a tuple for a * different target relation. */ ExecClearTuple(testslot); epqstate->relsubs_blocked[rti - 1] = true; return slot; } /* * EvalPlanQualInit -- initialize during creation of a plan state node * that might need to invoke EPQ processing. * * If the caller intends to use EvalPlanQual(), resultRelations should be * a list of RT indexes of potential target relations for EvalPlanQual(), * and we will arrange that the other listed relations don't return any * tuple during an EvalPlanQual() call. Otherwise resultRelations * should be NIL. * * Note: subplan/auxrowmarks can be NULL/NIL if they will be set later * with EvalPlanQualSetPlan. */ void EvalPlanQualInit(EPQState *epqstate, EState *parentestate, Plan *subplan, List *auxrowmarks, int epqParam, List *resultRelations) { Index rtsize = parentestate->es_range_table_size; /* initialize data not changing over EPQState's lifetime */ epqstate->parentestate = parentestate; epqstate->epqParam = epqParam; epqstate->resultRelations = resultRelations; /* * Allocate space to reference a slot for each potential rti - do so now * rather than in EvalPlanQualBegin(), as done for other dynamically * allocated resources, so EvalPlanQualSlot() can be used to hold tuples * that *may* need EPQ later, without forcing the overhead of * EvalPlanQualBegin(). */ epqstate->tuple_table = NIL; epqstate->relsubs_slot = (TupleTableSlot **) palloc0(rtsize * sizeof(TupleTableSlot *)); /* ... and remember data that EvalPlanQualBegin will need */ epqstate->plan = subplan; epqstate->arowMarks = auxrowmarks; /* ... and mark the EPQ state inactive */ epqstate->origslot = NULL; epqstate->recheckestate = NULL; epqstate->recheckplanstate = NULL; epqstate->relsubs_rowmark = NULL; epqstate->relsubs_done = NULL; epqstate->relsubs_blocked = NULL; } /* * EvalPlanQualSetPlan -- set or change subplan of an EPQState. * * We used to need this so that ModifyTable could deal with multiple subplans. * It could now be refactored out of existence. */ void EvalPlanQualSetPlan(EPQState *epqstate, Plan *subplan, List *auxrowmarks) { /* If we have a live EPQ query, shut it down */ EvalPlanQualEnd(epqstate); /* And set/change the plan pointer */ epqstate->plan = subplan; /* The rowmarks depend on the plan, too */ epqstate->arowMarks = auxrowmarks; } /* * Return, and create if necessary, a slot for an EPQ test tuple. * * Note this only requires EvalPlanQualInit() to have been called, * EvalPlanQualBegin() is not necessary. */ TupleTableSlot * EvalPlanQualSlot(EPQState *epqstate, Relation relation, Index rti) { TupleTableSlot **slot; Assert(relation); Assert(rti > 0 && rti <= epqstate->parentestate->es_range_table_size); slot = &epqstate->relsubs_slot[rti - 1]; if (*slot == NULL) { MemoryContext oldcontext; oldcontext = MemoryContextSwitchTo(epqstate->parentestate->es_query_cxt); *slot = table_slot_create(relation, &epqstate->tuple_table); MemoryContextSwitchTo(oldcontext); } return *slot; } /* * Fetch the current row value for a non-locked relation, identified by rti, * that needs to be scanned by an EvalPlanQual operation. origslot must have * been set to contain the current result row (top-level row) that we need to * recheck. Returns true if a substitution tuple was found, false if not. */ bool EvalPlanQualFetchRowMark(EPQState *epqstate, Index rti, TupleTableSlot *slot) { ExecAuxRowMark *earm = epqstate->relsubs_rowmark[rti - 1]; ExecRowMark *erm; Datum datum; bool isNull; Assert(earm != NULL); Assert(epqstate->origslot != NULL); erm = earm->rowmark; if (RowMarkRequiresRowShareLock(erm->markType)) elog(ERROR, "EvalPlanQual doesn't support locking rowmarks"); /* if child rel, must check whether it produced this row */ if (erm->rti != erm->prti) { Oid tableoid; datum = ExecGetJunkAttribute(epqstate->origslot, earm->toidAttNo, &isNull); /* non-locked rels could be on the inside of outer joins */ if (isNull) return false; tableoid = DatumGetObjectId(datum); Assert(OidIsValid(erm->relid)); if (tableoid != erm->relid) { /* this child is inactive right now */ return false; } } if (erm->markType == ROW_MARK_REFERENCE) { Assert(erm->relation != NULL); /* fetch the tuple's ctid */ datum = ExecGetJunkAttribute(epqstate->origslot, earm->ctidAttNo, &isNull); /* non-locked rels could be on the inside of outer joins */ if (isNull) return false; /* fetch requests on foreign tables must be passed to their FDW */ if (erm->relation->rd_rel->relkind == RELKIND_FOREIGN_TABLE) { FdwRoutine *fdwroutine; bool updated = false; fdwroutine = GetFdwRoutineForRelation(erm->relation, false); /* this should have been checked already, but let's be safe */ if (fdwroutine->RefetchForeignRow == NULL) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot lock rows in foreign table \"%s\"", RelationGetRelationName(erm->relation)))); fdwroutine->RefetchForeignRow(epqstate->recheckestate, erm, datum, slot, &updated); if (TupIsNull(slot)) elog(ERROR, "failed to fetch tuple for EvalPlanQual recheck"); /* * Ideally we'd insist on updated == false here, but that assumes * that FDWs can track that exactly, which they might not be able * to. So just ignore the flag. */ return true; } else { /* ordinary table, fetch the tuple */ if (!table_tuple_fetch_row_version(erm->relation, (ItemPointer) DatumGetPointer(datum), SnapshotAny, slot)) elog(ERROR, "failed to fetch tuple for EvalPlanQual recheck"); return true; } } else { Assert(erm->markType == ROW_MARK_COPY); /* fetch the whole-row Var for the relation */ datum = ExecGetJunkAttribute(epqstate->origslot, earm->wholeAttNo, &isNull); /* non-locked rels could be on the inside of outer joins */ if (isNull) return false; ExecStoreHeapTupleDatum(datum, slot); return true; } } /* * Fetch the next row (if any) from EvalPlanQual testing * * (In practice, there should never be more than one row...) */ TupleTableSlot * EvalPlanQualNext(EPQState *epqstate) { MemoryContext oldcontext; TupleTableSlot *slot; oldcontext = MemoryContextSwitchTo(epqstate->recheckestate->es_query_cxt); slot = ExecProcNode(epqstate->recheckplanstate); MemoryContextSwitchTo(oldcontext); return slot; } /* * Initialize or reset an EvalPlanQual state tree */ void EvalPlanQualBegin(EPQState *epqstate) { EState *parentestate = epqstate->parentestate; EState *recheckestate = epqstate->recheckestate; if (recheckestate == NULL) { /* First time through, so create a child EState */ EvalPlanQualStart(epqstate, epqstate->plan); } else { /* * We already have a suitable child EPQ tree, so just reset it. */ Index rtsize = parentestate->es_range_table_size; PlanState *rcplanstate = epqstate->recheckplanstate; /* * Reset the relsubs_done[] flags to equal relsubs_blocked[], so that * the EPQ run will never attempt to fetch tuples from blocked target * relations. */ memcpy(epqstate->relsubs_done, epqstate->relsubs_blocked, rtsize * sizeof(bool)); /* Recopy current values of parent parameters */ if (parentestate->es_plannedstmt->paramExecTypes != NIL) { int i; /* * Force evaluation of any InitPlan outputs that could be needed * by the subplan, just in case they got reset since * EvalPlanQualStart (see comments therein). */ ExecSetParamPlanMulti(rcplanstate->plan->extParam, GetPerTupleExprContext(parentestate)); i = list_length(parentestate->es_plannedstmt->paramExecTypes); while (--i >= 0) { /* copy value if any, but not execPlan link */ recheckestate->es_param_exec_vals[i].value = parentestate->es_param_exec_vals[i].value; recheckestate->es_param_exec_vals[i].isnull = parentestate->es_param_exec_vals[i].isnull; } } /* * Mark child plan tree as needing rescan at all scan nodes. The * first ExecProcNode will take care of actually doing the rescan. */ rcplanstate->chgParam = bms_add_member(rcplanstate->chgParam, epqstate->epqParam); } } /* * Start execution of an EvalPlanQual plan tree. * * 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(EPQState *epqstate, Plan *planTree) { EState *parentestate = epqstate->parentestate; Index rtsize = parentestate->es_range_table_size; EState *rcestate; MemoryContext oldcontext; ListCell *l; epqstate->recheckestate = rcestate = CreateExecutorState(); oldcontext = MemoryContextSwitchTo(rcestate->es_query_cxt); /* signal that this is an EState for executing EPQ */ rcestate->es_epq_active = epqstate; /* * Child EPQ EStates share the parent's copy of unchanging state such as * the snapshot, rangetable, and external Param info. They need their own * copies of local state, including a tuple table, es_param_exec_vals, * result-rel info, etc. */ rcestate->es_direction = ForwardScanDirection; rcestate->es_snapshot = parentestate->es_snapshot; rcestate->es_crosscheck_snapshot = parentestate->es_crosscheck_snapshot; rcestate->es_range_table = parentestate->es_range_table; rcestate->es_range_table_size = parentestate->es_range_table_size; rcestate->es_relations = parentestate->es_relations; rcestate->es_rowmarks = parentestate->es_rowmarks; rcestate->es_rteperminfos = parentestate->es_rteperminfos; rcestate->es_plannedstmt = parentestate->es_plannedstmt; rcestate->es_junkFilter = parentestate->es_junkFilter; rcestate->es_output_cid = parentestate->es_output_cid; rcestate->es_queryEnv = parentestate->es_queryEnv; /* * ResultRelInfos needed by subplans are initialized from scratch when the * subplans themselves are initialized. */ rcestate->es_result_relations = NULL; /* es_trig_target_relations must NOT be copied */ rcestate->es_top_eflags = parentestate->es_top_eflags; rcestate->es_instrument = parentestate->es_instrument; /* es_auxmodifytables must NOT be copied */ /* * The external param list is simply shared from parent. The internal * param workspace has to be local state, but we copy the initial values * from the parent, so as to have access to any param values that were * already set from other parts of the parent's plan tree. */ rcestate->es_param_list_info = parentestate->es_param_list_info; if (parentestate->es_plannedstmt->paramExecTypes != NIL) { int i; /* * Force evaluation of any InitPlan outputs that could be needed by * the subplan. (With more complexity, maybe we could postpone this * till the subplan actually demands them, but it doesn't seem worth * the trouble; this is a corner case already, since usually the * InitPlans would have been evaluated before reaching EvalPlanQual.) * * This will not touch output params of InitPlans that occur somewhere * within the subplan tree, only those that are attached to the * ModifyTable node or above it and are referenced within the subplan. * That's OK though, because the planner would only attach such * InitPlans to a lower-level SubqueryScan node, and EPQ execution * will not descend into a SubqueryScan. * * The EState's per-output-tuple econtext is sufficiently short-lived * for this, since it should get reset before there is any chance of * doing EvalPlanQual again. */ ExecSetParamPlanMulti(planTree->extParam, GetPerTupleExprContext(parentestate)); /* now make the internal param workspace ... */ i = list_length(parentestate->es_plannedstmt->paramExecTypes); rcestate->es_param_exec_vals = (ParamExecData *) palloc0(i * sizeof(ParamExecData)); /* ... and copy down all values, whether really needed or not */ while (--i >= 0) { /* copy value if any, but not execPlan link */ rcestate->es_param_exec_vals[i].value = parentestate->es_param_exec_vals[i].value; rcestate->es_param_exec_vals[i].isnull = parentestate->es_param_exec_vals[i].isnull; } } /* * Copy es_unpruned_relids so that pruned relations are ignored by * ExecInitLockRows() and ExecInitModifyTable() when initializing the plan * trees below. */ rcestate->es_unpruned_relids = parentestate->es_unpruned_relids; /* * 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(rcestate->es_subplanstates == NIL); foreach(l, parentestate->es_plannedstmt->subplans) { Plan *subplan = (Plan *) lfirst(l); PlanState *subplanstate; subplanstate = ExecInitNode(subplan, rcestate, 0); rcestate->es_subplanstates = lappend(rcestate->es_subplanstates, subplanstate); } /* * Build an RTI indexed array of rowmarks, so that * EvalPlanQualFetchRowMark() can efficiently access the to be fetched * rowmark. */ epqstate->relsubs_rowmark = (ExecAuxRowMark **) palloc0(rtsize * sizeof(ExecAuxRowMark *)); foreach(l, epqstate->arowMarks) { ExecAuxRowMark *earm = (ExecAuxRowMark *) lfirst(l); epqstate->relsubs_rowmark[earm->rowmark->rti - 1] = earm; } /* * Initialize per-relation EPQ tuple states. Result relations, if any, * get marked as blocked; others as not-fetched. */ epqstate->relsubs_done = palloc_array(bool, rtsize); epqstate->relsubs_blocked = palloc0_array(bool, rtsize); foreach(l, epqstate->resultRelations) { int rtindex = lfirst_int(l); Assert(rtindex > 0 && rtindex <= rtsize); epqstate->relsubs_blocked[rtindex - 1] = true; } memcpy(epqstate->relsubs_done, epqstate->relsubs_blocked, rtsize * sizeof(bool)); /* * 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. */ epqstate->recheckplanstate = ExecInitNode(planTree, rcestate, 0); MemoryContextSwitchTo(oldcontext); } /* * EvalPlanQualEnd -- shut down at termination of parent plan state node, * or if we are done with the current EPQ child. * * 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 * result and trigger target relations that got opened, since those are not * shared. (There probably shouldn't be any of the latter, but just in * case...) */ void EvalPlanQualEnd(EPQState *epqstate) { EState *estate = epqstate->recheckestate; Index rtsize; MemoryContext oldcontext; ListCell *l; rtsize = epqstate->parentestate->es_range_table_size; /* * We may have a tuple table, even if EPQ wasn't started, because we allow * use of EvalPlanQualSlot() without calling EvalPlanQualBegin(). */ if (epqstate->tuple_table != NIL) { memset(epqstate->relsubs_slot, 0, rtsize * sizeof(TupleTableSlot *)); ExecResetTupleTable(epqstate->tuple_table, true); epqstate->tuple_table = NIL; } /* EPQ wasn't started, nothing further to do */ if (estate == NULL) return; oldcontext = MemoryContextSwitchTo(estate->es_query_cxt); ExecEndNode(epqstate->recheckplanstate); foreach(l, estate->es_subplanstates) { PlanState *subplanstate = (PlanState *) lfirst(l); ExecEndNode(subplanstate); } /* throw away the per-estate tuple table, some node may have used it */ ExecResetTupleTable(estate->es_tupleTable, false); /* Close any result and trigger target relations attached to this EState */ ExecCloseResultRelations(estate); MemoryContextSwitchTo(oldcontext); FreeExecutorState(estate); /* Mark EPQState idle */ epqstate->origslot = NULL; epqstate->recheckestate = NULL; epqstate->recheckplanstate = NULL; epqstate->relsubs_rowmark = NULL; epqstate->relsubs_done = NULL; epqstate->relsubs_blocked = NULL; }