From bca61cd199970ae050dc74b4a7d2d7b275ad0ce0 Mon Sep 17 00:00:00 2001 From: Bharath Rupireddy Date: Wed, 14 Oct 2020 14:25:24 +0530 Subject: [PATCH v2] Parallel Inserts in CREATE TABLE AS The idea of this patch is to allow the leader and each worker insert the tuples in parallel if the SELECT part of the CTAS is parallelizable. The design: Let the planner know that the SELECT is from CTAS in createas.c so that it can set the number of tuples transferred from the workers to Gather node to 0. With this change, there are chances that the planner may choose the parallel plan. After the planning, check if the upper plan node is Gather in createas.c and mark a parallelism flag in the CTAS dest receiver. Pass the into clause, object id, command id from the leader to workers, so that each worker can create its own CTAS dest receiver. Leader inserts it's share of tuples if instructed to do, and so are workers. Each worker writes atomically it's number of inserted tuples into a shared memory variable, the leader combines this with it's own number of inserted tuples and shares to the client. --- src/backend/access/heap/heapam.c | 11 - src/backend/access/transam/xact.c | 14 ++ src/backend/commands/createas.c | 321 ++++++++++++++++---------- src/backend/commands/explain.c | 19 ++ src/backend/executor/execMain.c | 19 ++ src/backend/executor/execParallel.c | 61 ++++- src/backend/executor/nodeGather.c | 97 +++++++- src/backend/optimizer/path/costsize.c | 12 + src/include/access/xact.h | 1 + src/include/commands/createas.h | 18 ++ src/include/executor/execParallel.h | 1 + src/include/nodes/execnodes.h | 5 + src/include/nodes/parsenodes.h | 1 + 13 files changed, 437 insertions(+), 143 deletions(-) diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index 1585861a02..1602525d4a 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -2043,17 +2043,6 @@ static HeapTuple heap_prepare_insert(Relation relation, HeapTuple tup, TransactionId xid, CommandId cid, int options) { - /* - * To allow parallel inserts, we need to ensure that they are safe to be - * performed in workers. We have the infrastructure to allow parallel - * inserts in general except for the cases where inserts generate a new - * CommandId (eg. inserts into a table having a foreign key column). - */ - if (IsParallelWorker()) - ereport(ERROR, - (errcode(ERRCODE_INVALID_TRANSACTION_STATE), - errmsg("cannot insert tuples in a parallel worker"))); - tup->t_data->t_infomask &= ~(HEAP_XACT_MASK); tup->t_data->t_infomask2 &= ~(HEAP2_XACT_MASK); tup->t_data->t_infomask |= HEAP_XMAX_INVALID; diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c index af6afcebb1..24eb8fca38 100644 --- a/src/backend/access/transam/xact.c +++ b/src/backend/access/transam/xact.c @@ -775,6 +775,20 @@ GetCurrentCommandId(bool used) return currentCommandId; } +/* + * SetCurrentCommandIdUsedForWorker + * + * For a parallel worker, record that the currentCommandId has been used. + * This must only be called at the start of a parallel operation. +*/ +void +SetCurrentCommandIdUsedForWorker(void) +{ + Assert(IsParallelWorker() && !currentCommandIdUsed && currentCommandId != InvalidCommandId); + + currentCommandIdUsed = true; +} + /* * SetParallelStartTimestamps * diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c index d53ec952d0..a3ab772389 100644 --- a/src/backend/commands/createas.c +++ b/src/backend/commands/createas.c @@ -51,18 +51,6 @@ #include "utils/rls.h" #include "utils/snapmgr.h" -typedef struct -{ - DestReceiver pub; /* publicly-known function pointers */ - IntoClause *into; /* target relation specification */ - /* These fields are filled by intorel_startup: */ - Relation rel; /* relation to write to */ - ObjectAddress reladdr; /* address of rel, for ExecCreateTableAs */ - CommandId output_cid; /* cmin to insert in output tuples */ - int ti_options; /* table_tuple_insert performance options */ - BulkInsertState bistate; /* bulk insert state */ -} DR_intorel; - /* utility functions for CTAS definition creation */ static ObjectAddress create_ctas_internal(List *attrList, IntoClause *into); static ObjectAddress create_ctas_nodata(List *tlist, IntoClause *into); @@ -328,10 +316,28 @@ ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt, query = linitial_node(Query, rewritten); Assert(query->commandType == CMD_SELECT); + /* + * Flag to let the planner know that the SELECT query is for + * CREATE TABLE AS. This is used to make the number tuples + * transferred from workers to gather node(in case parallelism + * kicks in for the SELECT part of the CTAS), to zero as each + * worker will parallelly insert it's share of tuples. + */ + if (IsParallelInsertInCTASAllowed(into, NULL)) + query->isForCTAS = true; + /* plan the query */ plan = pg_plan_query(query, pstate->p_sourcetext, CURSOR_OPT_PARALLEL_OK, params); + /* + * SELECT part of the CTAS is parallelizable, so we can make + * each parallel worker insert the tuples that are resulted + * in it's execution into the target table. + */ + if (IsParallelInsertInCTASAllowed(into, plan)) + ((DR_intorel *) dest)->is_parallel = true; + /* * Use a snapshot with an updated command ID to ensure this query sees * results of any previously executed queries. (This could only @@ -418,6 +424,9 @@ CreateIntoRelDestReceiver(IntoClause *intoClause) self->pub.rDestroy = intorel_destroy; self->pub.mydest = DestIntoRel; self->into = intoClause; + self->is_parallel = false; + self->is_parallel_worker = false; + self->object_id = InvalidOid; /* other private fields will be set during intorel_startup */ return (DestReceiver *) self; @@ -430,135 +439,180 @@ static void intorel_startup(DestReceiver *self, int operation, TupleDesc typeinfo) { DR_intorel *myState = (DR_intorel *) self; - IntoClause *into = myState->into; - bool is_matview; - char relkind; - List *attrList; ObjectAddress intoRelationAddr; Relation intoRelationDesc; - RangeTblEntry *rte; - ListCell *lc; - int attnum; - - Assert(into != NULL); /* else somebody forgot to set it */ - /* This code supports both CREATE TABLE AS and CREATE MATERIALIZED VIEW */ - is_matview = (into->viewQuery != NULL); - relkind = is_matview ? RELKIND_MATVIEW : RELKIND_RELATION; + if (myState->is_parallel_worker) + { + /* In the worker */ + intoRelationDesc = table_open(myState->object_id, AccessExclusiveLock); + myState->rel = intoRelationDesc; + myState->reladdr = InvalidObjectAddress; + myState->ti_options = 0; + myState->bistate = GetBulkInsertState(); - /* - * Build column definitions using "pre-cooked" type and collation info. If - * a column name list was specified in CREATE TABLE AS, override the - * column names derived from the query. (Too few column names are OK, too - * many are not.) - */ - attrList = NIL; - lc = list_head(into->colNames); - for (attnum = 0; attnum < typeinfo->natts; attnum++) + /* + * Right after the table is created in the leader, the command id is + * incremented (in create_ctas_internal()). The new command id is + * marked as used in inintorel_startup(), then the parallel mode is + * entered. The command id and transaction id are serialized into + * parallel DSM, they are then available to all parallel workers. All + * the workers need to mark the command id as used before insertion. + */ + (void) SetCurrentCommandIdUsedForWorker(); + myState->output_cid = GetCurrentCommandId(false); + } + else { - Form_pg_attribute attribute = TupleDescAttr(typeinfo, attnum); - ColumnDef *col; - char *colname; + IntoClause *into = myState->into; + bool is_matview; + char relkind; + List *attrList; + Relation intoRelationDesc; + RangeTblEntry *rte; + ListCell *lc; + int attnum; - if (lc) - { - colname = strVal(lfirst(lc)); - lc = lnext(into->colNames, lc); - } - else - colname = NameStr(attribute->attname); + Assert(into != NULL); /* else somebody forgot to set it */ - col = makeColumnDef(colname, - attribute->atttypid, - attribute->atttypmod, - attribute->attcollation); + /* This code supports both CREATE TABLE AS and CREATE MATERIALIZED VIEW */ + is_matview = (into->viewQuery != NULL); + relkind = is_matview ? RELKIND_MATVIEW : RELKIND_RELATION; /* - * It's possible that the column is of a collatable type but the - * collation could not be resolved, so double-check. (We must check - * this here because DefineRelation would adopt the type's default - * collation rather than complaining.) - */ - if (!OidIsValid(col->collOid) && - type_is_collatable(col->typeName->typeOid)) - ereport(ERROR, - (errcode(ERRCODE_INDETERMINATE_COLLATION), - errmsg("no collation was derived for column \"%s\" with collatable type %s", - col->colname, - format_type_be(col->typeName->typeOid)), - errhint("Use the COLLATE clause to set the collation explicitly."))); + * Build column definitions using "pre-cooked" type and collation info. If + * a column name list was specified in CREATE TABLE AS, override the + * column names derived from the query. (Too few column names are OK, too + * many are not.) + */ + attrList = NIL; + lc = list_head(into->colNames); + for (attnum = 0; attnum < typeinfo->natts; attnum++) + { + Form_pg_attribute attribute = TupleDescAttr(typeinfo, attnum); + ColumnDef *col; + char *colname; - attrList = lappend(attrList, col); - } + if (lc) + { + colname = strVal(lfirst(lc)); + lc = lnext(into->colNames, lc); + } + else + colname = NameStr(attribute->attname); - if (lc != NULL) - ereport(ERROR, - (errcode(ERRCODE_SYNTAX_ERROR), - errmsg("too many column names were specified"))); + col = makeColumnDef(colname, + attribute->atttypid, + attribute->atttypmod, + attribute->attcollation); - /* - * Actually create the target table - */ - intoRelationAddr = create_ctas_internal(attrList, into); + /* + * It's possible that the column is of a collatable type but the + * collation could not be resolved, so double-check. (We must check + * this here because DefineRelation would adopt the type's default + * collation rather than complaining.) + */ + if (!OidIsValid(col->collOid) && + type_is_collatable(col->typeName->typeOid)) + ereport(ERROR, + (errcode(ERRCODE_INDETERMINATE_COLLATION), + errmsg("no collation was derived for column \"%s\" with collatable type %s", + col->colname, + format_type_be(col->typeName->typeOid)), + errhint("Use the COLLATE clause to set the collation explicitly."))); - /* - * Finally we can open the target table - */ - intoRelationDesc = table_open(intoRelationAddr.objectId, AccessExclusiveLock); + attrList = lappend(attrList, col); + } - /* - * Check INSERT permission on the constructed table. - * - * XXX: It would arguably make sense to skip this check if into->skipData - * is true. - */ - rte = makeNode(RangeTblEntry); - rte->rtekind = RTE_RELATION; - rte->relid = intoRelationAddr.objectId; - rte->relkind = relkind; - rte->rellockmode = RowExclusiveLock; - rte->requiredPerms = ACL_INSERT; + if (lc != NULL) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("too many column names were specified"))); - for (attnum = 1; attnum <= intoRelationDesc->rd_att->natts; attnum++) - rte->insertedCols = bms_add_member(rte->insertedCols, - attnum - FirstLowInvalidHeapAttributeNumber); + /* + * Actually create the target table + */ + intoRelationAddr = create_ctas_internal(attrList, into); - ExecCheckRTPerms(list_make1(rte), true); + /* + * Finally we can open the target table + */ + intoRelationDesc = table_open(intoRelationAddr.objectId, AccessExclusiveLock); - /* - * Make sure the constructed table does not have RLS enabled. - * - * check_enable_rls() will ereport(ERROR) itself if the user has requested - * something invalid, and otherwise will return RLS_ENABLED if RLS should - * be enabled here. We don't actually support that currently, so throw - * our own ereport(ERROR) if that happens. - */ - if (check_enable_rls(intoRelationAddr.objectId, InvalidOid, false) == RLS_ENABLED) - ereport(ERROR, - (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), - errmsg("policies not yet implemented for this command"))); + /* + * Check INSERT permission on the constructed table. + * + * XXX: It would arguably make sense to skip this check if into->skipData + * is true. + */ + rte = makeNode(RangeTblEntry); + rte->rtekind = RTE_RELATION; + rte->relid = intoRelationAddr.objectId; + rte->relkind = relkind; + rte->rellockmode = RowExclusiveLock; + rte->requiredPerms = ACL_INSERT; + + for (attnum = 1; attnum <= intoRelationDesc->rd_att->natts; attnum++) + rte->insertedCols = bms_add_member(rte->insertedCols, + attnum - FirstLowInvalidHeapAttributeNumber); + + ExecCheckRTPerms(list_make1(rte), true); - /* - * Tentatively mark the target as populated, if it's a matview and we're - * going to fill it; otherwise, no change needed. - */ - if (is_matview && !into->skipData) - SetMatViewPopulatedState(intoRelationDesc, true); + /* + * Make sure the constructed table does not have RLS enabled. + * + * check_enable_rls() will ereport(ERROR) itself if the user has requested + * something invalid, and otherwise will return RLS_ENABLED if RLS should + * be enabled here. We don't actually support that currently, so throw + * our own ereport(ERROR) if that happens. + */ + if (check_enable_rls(intoRelationAddr.objectId, InvalidOid, false) == RLS_ENABLED) + ereport(ERROR, + (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("policies not yet implemented for this command"))); - /* - * Fill private fields of myState for use by later routines - */ - myState->rel = intoRelationDesc; - myState->reladdr = intoRelationAddr; - myState->output_cid = GetCurrentCommandId(true); - myState->ti_options = TABLE_INSERT_SKIP_FSM; - myState->bistate = GetBulkInsertState(); + /* + * Tentatively mark the target as populated, if it's a matview and we're + * going to fill it; otherwise, no change needed. + */ + if (is_matview && !into->skipData) + SetMatViewPopulatedState(intoRelationDesc, true); - /* - * Valid smgr_targblock implies something already wrote to the relation. - * This may be harmless, but this function hasn't planned for it. - */ - Assert(RelationGetTargetBlock(intoRelationDesc) == InvalidBlockNumber); + /* + * Fill private fields of myState for use by later routines + */ + myState->rel = intoRelationDesc; + myState->reladdr = intoRelationAddr; + myState->output_cid = GetCurrentCommandId(true); + myState->ti_options = TABLE_INSERT_SKIP_FSM; + myState->bistate = GetBulkInsertState(); + + /* + * Valid smgr_targblock implies something already wrote to the relation. + * This may be harmless, but this function hasn't planned for it. + */ + Assert(RelationGetTargetBlock(intoRelationDesc) == InvalidBlockNumber); + + if (myState->is_parallel == true) + { + myState->object_id = intoRelationAddr.objectId; + + /* + * We don't need to skip contacting FSM while inserting tuples + * for parallel mode, while extending the relations, workers + * instead of blocking on a page while another worker is inserting, + * can check the FSM for another page that can accommodate the + * tuples. This results in major benefit for parallel inserts. + */ + myState->ti_options = 0; + + /* + * rd_createSubid is marked invalid, otherwise, the table is + * not allowed to extend by the workers. + */ + myState->rel->rd_createSubid = InvalidSubTransactionId; + } + } } /* @@ -614,3 +668,28 @@ intorel_destroy(DestReceiver *self) { pfree(self); } + +/* + * IsParallelInsertInCTASAllowed --- determine whether or not parallel + * insertion is possible. + */ +bool IsParallelInsertInCTASAllowed(IntoClause *into, PlannedStmt *plannedstmt) +{ + bool allowed = false; + + if (into != NULL && + into->type == T_IntoClause) + { + if (into->viewQuery == NULL && + into->rel->relpersistence != RELPERSISTENCE_TEMP) + allowed = true; + + if (plannedstmt != NULL && allowed) + { + if (!IsA(plannedstmt->planTree, Gather)) + allowed = false; + } + } + + return allowed; +} \ No newline at end of file diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c index c8e292adfa..4cf6a3da44 100644 --- a/src/backend/commands/explain.c +++ b/src/backend/commands/explain.c @@ -371,6 +371,16 @@ ExplainOneQuery(Query *query, int cursorOptions, return; } + /* + * Flag to let the planner know that the SELECT query is for + * CREATE TABLE AS. This is used to make the number tuples + * transferred from workers to gather node(in case parallelism + * kicks in for the SELECT part of the CTAS), to zero as each + * worker will parallelly insert it's share of tuples. + */ + if (IsParallelInsertInCTASAllowed(into, NULL)) + query->isForCTAS = true; + /* if an advisor plugin is present, let it manage things */ if (ExplainOneQuery_hook) (*ExplainOneQuery_hook) (query, cursorOptions, into, es, @@ -536,7 +546,16 @@ ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es, * AS, we'd better use the appropriate tuple receiver. */ if (into) + { dest = CreateIntoRelDestReceiver(into); + /* + * SELECT part of the CTAS is parallelizable, so we can make + * each parallel worker insert the tuples that are resulted + * in it's execution into the target table. + */ + if (IsParallelInsertInCTASAllowed(into, plannedstmt)) + ((DR_intorel *) dest)->is_parallel = true; + } else dest = None_Receiver; diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c index 783eecbc13..7928e53295 100644 --- a/src/backend/executor/execMain.c +++ b/src/backend/executor/execMain.c @@ -45,6 +45,7 @@ #include "access/xact.h" #include "catalog/namespace.h" #include "catalog/pg_publication.h" +#include "commands/createas.h" #include "commands/matview.h" #include "commands/trigger.h" #include "executor/execdebug.h" @@ -352,6 +353,24 @@ standard_ExecutorRun(QueryDesc *queryDesc, if (sendTuples) dest->rStartup(dest, operation, queryDesc->tupDesc); + /* + * For parallelizing inserts in CTAS i.e. making each + * parallel worker inerst it's tuples, we must send + * information such as intoclause(for each worker + * building it's own dest receiver), object id(for each + * worker to open the table). + */ + if (queryDesc->plannedstmt->parallelModeNeeded == true && + dest != NULL && + dest->mydest == DestIntoRel && + ((DR_intorel *) dest)->is_parallel == true && + ((DR_intorel *) dest)->is_parallel_worker != true) + { + queryDesc->planstate->intoclause = ((DR_intorel *) dest)->into; + queryDesc->planstate->objectid = ((DR_intorel *) dest)->object_id; + queryDesc->planstate->dest = dest; + } + /* * run plan */ diff --git a/src/backend/executor/execParallel.c b/src/backend/executor/execParallel.c index befde52691..fd6f9429d0 100644 --- a/src/backend/executor/execParallel.c +++ b/src/backend/executor/execParallel.c @@ -23,6 +23,7 @@ #include "postgres.h" +#include "commands/createas.h" #include "executor/execParallel.h" #include "executor/executor.h" #include "executor/nodeAgg.h" @@ -65,6 +66,7 @@ #define PARALLEL_KEY_QUERY_TEXT UINT64CONST(0xE000000000000008) #define PARALLEL_KEY_JIT_INSTRUMENTATION UINT64CONST(0xE000000000000009) #define PARALLEL_KEY_WAL_USAGE UINT64CONST(0xE00000000000000A) +#define PARALLEL_KEY_INTO_CLAUSE UINT64CONST(0xE00000000000000B) #define PARALLEL_TUPLE_QUEUE_SIZE 65536 @@ -77,6 +79,8 @@ typedef struct FixedParallelExecutorState dsa_pointer param_exec; int eflags; int jit_flags; + Oid objectid; /* workers to open relation/table. */ + pg_atomic_uint64 processed; /* number tuples inserted by all the workers. */ } FixedParallelExecutorState; /* @@ -600,6 +604,7 @@ ExecInitParallelPlan(PlanState *planstate, EState *estate, Size dsa_minsize = dsa_minimum_size(); char *query_string; int query_len; + char *intoclausestr = NULL; /* * Force any initplan outputs that we're going to pass to workers to be @@ -712,6 +717,15 @@ ExecInitParallelPlan(PlanState *planstate, EState *estate, shm_toc_estimate_chunk(&pcxt->estimator, dsa_minsize); shm_toc_estimate_keys(&pcxt->estimator, 1); + /* Estimate space for into clause for CTAS. */ + if (planstate->intoclause != NULL && + planstate->intoclause->type == T_IntoClause) + { + intoclausestr = nodeToString(planstate->intoclause); + shm_toc_estimate_chunk(&pcxt->estimator, strlen(intoclausestr) + 1); + shm_toc_estimate_keys(&pcxt->estimator, 1); + } + /* Everyone's had a chance to ask for space, so now create the DSM. */ InitializeParallelDSM(pcxt); @@ -729,6 +743,15 @@ ExecInitParallelPlan(PlanState *planstate, EState *estate, fpes->param_exec = InvalidDsaPointer; fpes->eflags = estate->es_top_eflags; fpes->jit_flags = estate->es_jit_flags; + pg_atomic_init_u64(&fpes->processed, 0); + pei->processed = &fpes->processed; + + if (intoclausestr != NULL && + planstate->objectid != InvalidOid) + fpes->objectid = planstate->objectid; + else + fpes->objectid = InvalidOid; + shm_toc_insert(pcxt->toc, PARALLEL_KEY_EXECUTOR_FIXED, fpes); /* Store query string */ @@ -758,8 +781,17 @@ ExecInitParallelPlan(PlanState *planstate, EState *estate, shm_toc_insert(pcxt->toc, PARALLEL_KEY_WAL_USAGE, walusage_space); pei->wal_usage = walusage_space; + if (intoclausestr != NULL) + { + char *shmptr = (char *)shm_toc_allocate(pcxt->toc, + strlen(intoclausestr) + 1); + strcpy(shmptr, intoclausestr); + shm_toc_insert(pcxt->toc, PARALLEL_KEY_INTO_CLAUSE, shmptr); + } + /* Set up the tuple queues that the workers will write into. */ - pei->tqueue = ExecParallelSetupTupleQueues(pcxt, false); + if (intoclausestr == NULL) + pei->tqueue = ExecParallelSetupTupleQueues(pcxt, false); /* We don't need the TupleQueueReaders yet, though. */ pei->reader = NULL; @@ -1387,12 +1419,28 @@ ParallelQueryMain(dsm_segment *seg, shm_toc *toc) void *area_space; dsa_area *area; ParallelWorkerContext pwcxt; + char *intoclausestr = NULL; + IntoClause *intoclause = NULL; /* Get fixed-size state. */ fpes = shm_toc_lookup(toc, PARALLEL_KEY_EXECUTOR_FIXED, false); - /* Set up DestReceiver, SharedExecutorInstrumentation, and QueryDesc. */ - receiver = ExecParallelGetReceiver(seg, toc); + intoclausestr = shm_toc_lookup(toc, PARALLEL_KEY_INTO_CLAUSE, true); + if (intoclausestr != NULL) + { + /* + * If the worker is for parallel insert in CTAS, then use + * the proper dest receiver. + */ + intoclause = (IntoClause *) stringToNode(intoclausestr); + receiver = CreateIntoRelDestReceiver(intoclause); + ((DR_intorel *)receiver)->is_parallel_worker = true; + ((DR_intorel *)receiver)->object_id = fpes->objectid; + } + else + /* Set up DestReceiver, SharedExecutorInstrumentation, and QueryDesc. */ + receiver = ExecParallelGetReceiver(seg, toc); + instrumentation = shm_toc_lookup(toc, PARALLEL_KEY_INSTRUMENTATION, true); if (instrumentation != NULL) instrument_options = instrumentation->instrument_options; @@ -1471,6 +1519,13 @@ ParallelQueryMain(dsm_segment *seg, shm_toc *toc) queryDesc->estate->es_jit->instr; } + /* + * Write out the number of tuples this worker has inserted. Leader + * will use it to inform to the end client. + */ + if (intoclausestr != NULL) + pg_atomic_add_fetch_u64(&fpes->processed, queryDesc->estate->es_processed); + /* Must do this after capturing instrumentation. */ ExecutorEnd(queryDesc); diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c index a01b46af14..3c41094e0a 100644 --- a/src/backend/executor/nodeGather.c +++ b/src/backend/executor/nodeGather.c @@ -48,7 +48,7 @@ static TupleTableSlot *ExecGather(PlanState *pstate); static TupleTableSlot *gather_getnext(GatherState *gatherstate); static MinimalTuple gather_readnext(GatherState *gatherstate); static void ExecShutdownGatherWorkers(GatherState *node); - +static void ExecParallelInsertInCTAS(GatherState *node); /* ---------------------------------------------------------------- * ExecInitGather @@ -131,6 +131,66 @@ ExecInitGather(Gather *node, EState *estate, int eflags) return gatherstate; } +/* ---------------------------------------------------------------- + * ExecParallelInsertInCTAS(node) + * + * Facilitates parallel inserts by parallel workers and/or + * leader for Create Table AS. + * ---------------------------------------------------------------- + */ +static void +ExecParallelInsertInCTAS(GatherState *node) +{ + /* + * By now, for parallel workers (if launched any), + * would have started their work i.e. insertion to + * target table. + * In case the leader is chosen to participate for + * parallel inserts in CTAS, then finish it's share + * before going to wait for the parallel workers to + * finish. + */ + if (node->need_to_scan_locally == true && + node->ps.dest != NULL && + node->ps.dest->mydest == DestIntoRel) + { + EState *estate = node->ps.state; + TupleTableSlot *outerTupleSlot; + + for(;;) + { + /* Install our DSA area while executing the plan. */ + estate->es_query_dsa = + node->pei ? node->pei->area : NULL; + + outerTupleSlot = ExecProcNode(node->ps.lefttree); + + estate->es_query_dsa = NULL; + + if (!TupIsNull(outerTupleSlot)) + { + (void) node->ps.dest->receiveSlot(outerTupleSlot, node->ps.dest); + node->ps.state->es_processed++; + } + + if(TupIsNull(outerTupleSlot)) + break; + } + } + + /* Wait for the parallel workers to finish. */ + if (node->nworkers_launched > 0) + { + ExecShutdownGatherWorkers(node); + /* + * Add up the total tuples inserted by all workers, to + * the tuples inserted by the leader(if any). This will + * be shared to client. + */ + node->ps.state->es_processed += pg_atomic_read_u64(node->pei->processed); + } +} + /* ---------------------------------------------------------------- * ExecGather(node) * @@ -166,6 +226,17 @@ ExecGather(PlanState *pstate) { ParallelContext *pcxt; + /* + * Take the necessary information to be passed to workers for + * parallel inserts in CTAS. + */ + if (node->ps.intoclause != NULL && + node->ps.intoclause->type == T_IntoClause) + { + node->ps.lefttree->intoclause = node->ps.intoclause; + node->ps.lefttree->objectid = node->ps.objectid; + } + /* Initialize, or re-initialize, shared state needed by workers. */ if (!node->pei) node->pei = ExecInitParallelPlan(node->ps.lefttree, @@ -190,13 +261,17 @@ ExecGather(PlanState *pstate) /* Set up tuple queue readers to read the results. */ if (pcxt->nworkers_launched > 0) { - ExecParallelCreateReaders(node->pei); - /* Make a working array showing the active readers */ - node->nreaders = pcxt->nworkers_launched; - node->reader = (TupleQueueReader **) - palloc(node->nreaders * sizeof(TupleQueueReader *)); - memcpy(node->reader, node->pei->reader, - node->nreaders * sizeof(TupleQueueReader *)); + if (!(node->ps.intoclause != NULL && + node->ps.intoclause->type == T_IntoClause)) + { + ExecParallelCreateReaders(node->pei); + /* Make a working array showing the active readers */ + node->nreaders = pcxt->nworkers_launched; + node->reader = (TupleQueueReader **) + palloc(node->nreaders * sizeof(TupleQueueReader *)); + memcpy(node->reader, node->pei->reader, + node->nreaders * sizeof(TupleQueueReader *)); + } } else { @@ -220,6 +295,12 @@ ExecGather(PlanState *pstate) econtext = node->ps.ps_ExprContext; ResetExprContext(econtext); + if (node->ps.intoclause != NULL && + node->ps.intoclause->type == T_IntoClause) + { + ExecParallelInsertInCTAS(node); + return NULL; + } /* * Get next tuple, either from one of our workers, or by running the plan * ourselves. diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c index cd3716d494..9ed671415b 100644 --- a/src/backend/optimizer/path/costsize.c +++ b/src/backend/optimizer/path/costsize.c @@ -377,6 +377,18 @@ cost_gather(GatherPath *path, PlannerInfo *root, else path->path.rows = rel->rows; + /* + * Make the number of tuples that are transferred from + * workers to gather/leader node zero as each worker + * parallelly insert the tuples that are resulted from + * it's chunk of plan execution. This change may make + * the parallel plan cheap among all other plans, and + * influence the planner to consdier this parallel plan. + */ + if (root->parse->isForCTAS && + root->query_level == 1) + path->path.rows = 0; + startup_cost = path->subpath->startup_cost; run_cost = path->subpath->total_cost - path->subpath->startup_cost; diff --git a/src/include/access/xact.h b/src/include/access/xact.h index df1b43a932..1db154da63 100644 --- a/src/include/access/xact.h +++ b/src/include/access/xact.h @@ -388,6 +388,7 @@ extern FullTransactionId GetCurrentFullTransactionIdIfAny(void); extern void MarkCurrentTransactionIdLoggedIfAny(void); extern bool SubTransactionIsActive(SubTransactionId subxid); extern CommandId GetCurrentCommandId(bool used); +extern void SetCurrentCommandIdUsedForWorker(void); extern void SetParallelStartTimestamps(TimestampTz xact_ts, TimestampTz stmt_ts); extern TimestampTz GetCurrentTransactionStartTimestamp(void); extern TimestampTz GetCurrentStatementStartTimestamp(void); diff --git a/src/include/commands/createas.h b/src/include/commands/createas.h index 7629230254..d287c6b898 100644 --- a/src/include/commands/createas.h +++ b/src/include/commands/createas.h @@ -14,12 +14,28 @@ #ifndef CREATEAS_H #define CREATEAS_H +#include "access/heapam.h" #include "catalog/objectaddress.h" #include "nodes/params.h" +#include "nodes/plannodes.h" #include "parser/parse_node.h" #include "tcop/dest.h" #include "utils/queryenvironment.h" +typedef struct +{ + DestReceiver pub; /* publicly-known function pointers */ + IntoClause *into; /* target relation specification */ + /* These fields are filled by intorel_startup: */ + Relation rel; /* relation to write to */ + ObjectAddress reladdr; /* address of rel, for ExecCreateTableAs */ + CommandId output_cid; /* cmin to insert in output tuples */ + int ti_options; /* table_tuple_insert performance options */ + BulkInsertState bistate; /* bulk insert state */ + bool is_parallel; /* true if parallelism is to be considered */ + bool is_parallel_worker; /* true for parallel worker */ + Oid object_id; /* used for table open by parallel worker */ +} DR_intorel; extern ObjectAddress ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt, ParamListInfo params, QueryEnvironment *queryEnv, @@ -29,4 +45,6 @@ extern int GetIntoRelEFlags(IntoClause *intoClause); extern DestReceiver *CreateIntoRelDestReceiver(IntoClause *intoClause); +extern bool IsParallelInsertInCTASAllowed(IntoClause *intoClause, PlannedStmt *plannedstmt); + #endif /* CREATEAS_H */ diff --git a/src/include/executor/execParallel.h b/src/include/executor/execParallel.h index 5a39a5b29c..77f69946bf 100644 --- a/src/include/executor/execParallel.h +++ b/src/include/executor/execParallel.h @@ -35,6 +35,7 @@ typedef struct ParallelExecutorInfo /* These two arrays have pcxt->nworkers_launched entries: */ shm_mq_handle **tqueue; /* tuple queues for worker output */ struct TupleQueueReader **reader; /* tuple reader/writer support */ + volatile pg_atomic_uint64 *processed; /* number of tuples inserted by all workers */ } ParallelExecutorInfo; extern ParallelExecutorInfo *ExecInitParallelPlan(PlanState *planstate, diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h index a926ff1711..92eb1b34f0 100644 --- a/src/include/nodes/execnodes.h +++ b/src/include/nodes/execnodes.h @@ -23,6 +23,7 @@ #include "nodes/tidbitmap.h" #include "partitioning/partdefs.h" #include "storage/condition_variable.h" +#include "tcop/dest.h" #include "utils/hsearch.h" #include "utils/queryenvironment.h" #include "utils/reltrigger.h" @@ -1009,6 +1010,10 @@ typedef struct PlanState bool outeropsset; bool inneropsset; bool resultopsset; + /* Below is parallel inserts in CTAS related info. */ + IntoClause *intoclause; + Oid objectid; + DestReceiver *dest; } PlanState; /* ---------------- diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h index 60c2f45466..fe43dc941e 100644 --- a/src/include/nodes/parsenodes.h +++ b/src/include/nodes/parsenodes.h @@ -180,6 +180,7 @@ typedef struct Query */ int stmt_location; /* start location, or -1 if unknown */ int stmt_len; /* length in bytes; 0 means "rest of string" */ + bool isForCTAS; /* true if the select query is for create table as */ } Query; -- 2.25.1