diff options
Diffstat (limited to 'src/backend/tcop/pquery.c')
| -rw-r--r-- | src/backend/tcop/pquery.c | 93 |
1 files changed, 72 insertions, 21 deletions
diff --git a/src/backend/tcop/pquery.c b/src/backend/tcop/pquery.c index fca98fc0fa5..5a1c8b4867b 100644 --- a/src/backend/tcop/pquery.c +++ b/src/backend/tcop/pquery.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.86 2004/09/10 18:40:00 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.87 2004/09/13 20:07:05 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -32,6 +32,11 @@ Portal ActivePortal = NULL; +static void ProcessQuery(Query *parsetree, + Plan *plan, + ParamListInfo params, + DestReceiver *dest, + char *completionTag); static uint32 RunFromStore(Portal portal, ScanDirection direction, long count, DestReceiver *dest); static long PortalRunSelect(Portal portal, bool forward, long count, @@ -54,6 +59,8 @@ static void DoPortalRewind(Portal portal); QueryDesc * CreateQueryDesc(Query *parsetree, Plan *plantree, + Snapshot snapshot, + Snapshot crosscheck_snapshot, DestReceiver *dest, ParamListInfo params, bool doInstrument) @@ -63,6 +70,8 @@ CreateQueryDesc(Query *parsetree, qd->operation = parsetree->commandType; /* operation */ qd->parsetree = parsetree; /* parse tree */ qd->plantree = plantree; /* plan */ + qd->snapshot = snapshot; /* snapshot */ + qd->crosscheck_snapshot = crosscheck_snapshot; /* RI check snapshot */ qd->dest = dest; /* output dest */ qd->params = params; /* parameter values passed into query */ qd->doInstrument = doInstrument; /* instrumentation wanted? */ @@ -90,7 +99,7 @@ FreeQueryDesc(QueryDesc *qdesc) /* * ProcessQuery - * Execute a single query + * Execute a single plannable query within a PORTAL_MULTI_QUERY portal * * parsetree: the query tree * plan: the plan tree for the query @@ -104,7 +113,7 @@ FreeQueryDesc(QueryDesc *qdesc) * Must be called in a memory context that will be reset or deleted on * error; otherwise the executor's memory usage will be leaked. */ -void +static void ProcessQuery(Query *parsetree, Plan *plan, ParamListInfo params, @@ -114,6 +123,9 @@ ProcessQuery(Query *parsetree, int operation = parsetree->commandType; QueryDesc *queryDesc; + ereport(DEBUG3, + (errmsg_internal("ProcessQuery"))); + /* * Check for special-case destinations */ @@ -133,9 +145,17 @@ ProcessQuery(Query *parsetree, } /* + * Must always set snapshot for plannable queries. Note we assume + * that caller will take care of restoring ActiveSnapshot on exit/error. + */ + ActiveSnapshot = CopySnapshot(GetTransactionSnapshot()); + + /* * Create the QueryDesc object */ - queryDesc = CreateQueryDesc(parsetree, plan, dest, params, false); + queryDesc = CreateQueryDesc(parsetree, plan, + ActiveSnapshot, InvalidSnapshot, + dest, params, false); /* * Set up to collect AFTER triggers @@ -145,7 +165,7 @@ ProcessQuery(Query *parsetree, /* * Call ExecStart to prepare the plan for execution */ - ExecutorStart(queryDesc, false, false); + ExecutorStart(queryDesc, false); /* * Run the plan to completion. @@ -195,6 +215,9 @@ ProcessQuery(Query *parsetree, AfterTriggerEndQuery(); FreeQueryDesc(queryDesc); + + FreeSnapshot(ActiveSnapshot); + ActiveSnapshot = NULL; } /* @@ -238,13 +261,19 @@ ChoosePortalStrategy(List *parseTrees) * the query, they must be passed in here (caller is responsible for * giving them appropriate lifetime). * + * The caller can optionally pass a snapshot to be used; pass InvalidSnapshot + * for the normal behavior of setting a new snapshot. This parameter is + * presently ignored for non-PORTAL_ONE_SELECT portals (it's only intended + * to be used for cursors). + * * On return, portal is ready to accept PortalRun() calls, and the result * tupdesc (if any) is known. */ void -PortalStart(Portal portal, ParamListInfo params) +PortalStart(Portal portal, ParamListInfo params, Snapshot snapshot) { Portal saveActivePortal; + Snapshot saveActiveSnapshot; ResourceOwner saveResourceOwner; MemoryContext savePortalContext; MemoryContext oldContext; @@ -259,11 +288,13 @@ PortalStart(Portal portal, ParamListInfo params) * QueryContext?) */ saveActivePortal = ActivePortal; + saveActiveSnapshot = ActiveSnapshot; saveResourceOwner = CurrentResourceOwner; savePortalContext = PortalContext; PG_TRY(); { ActivePortal = portal; + ActiveSnapshot = NULL; /* will be set later */ CurrentResourceOwner = portal->resowner; PortalContext = PortalGetHeapMemory(portal); @@ -285,9 +316,13 @@ PortalStart(Portal portal, ParamListInfo params) case PORTAL_ONE_SELECT: /* - * Must set query snapshot before starting executor. + * Must set snapshot before starting executor. Be sure to + * copy it into the portal's context. */ - SetQuerySnapshot(); + if (snapshot) + ActiveSnapshot = CopySnapshot(snapshot); + else + ActiveSnapshot = CopySnapshot(GetTransactionSnapshot()); /* * Create QueryDesc in portal's context; for the moment, @@ -295,6 +330,8 @@ PortalStart(Portal portal, ParamListInfo params) */ queryDesc = CreateQueryDesc((Query *) linitial(portal->parseTrees), (Plan *) linitial(portal->planTrees), + ActiveSnapshot, + InvalidSnapshot, None_Receiver, params, false); @@ -309,7 +346,7 @@ PortalStart(Portal portal, ParamListInfo params) /* * Call ExecStart to prepare the plan for execution */ - ExecutorStart(queryDesc, false, false); + ExecutorStart(queryDesc, false); /* * This tells PortalCleanup to shut down the executor @@ -333,8 +370,8 @@ PortalStart(Portal portal, ParamListInfo params) case PORTAL_UTIL_SELECT: /* - * We don't set query snapshot here, because - * PortalRunUtility will take care of it. + * We don't set snapshot here, because + * PortalRunUtility will take care of it if needed. */ portal->tupDesc = UtilityTupleDescriptor(((Query *) linitial(portal->parseTrees))->utilityStmt); @@ -361,6 +398,7 @@ PortalStart(Portal portal, ParamListInfo params) /* Restore global vars and propagate error */ ActivePortal = saveActivePortal; + ActiveSnapshot = saveActiveSnapshot; CurrentResourceOwner = saveResourceOwner; PortalContext = savePortalContext; @@ -371,6 +409,7 @@ PortalStart(Portal portal, ParamListInfo params) MemoryContextSwitchTo(oldContext); ActivePortal = saveActivePortal; + ActiveSnapshot = saveActiveSnapshot; CurrentResourceOwner = saveResourceOwner; PortalContext = savePortalContext; @@ -453,6 +492,7 @@ PortalRun(Portal portal, long count, { bool result; Portal saveActivePortal; + Snapshot saveActiveSnapshot; ResourceOwner saveResourceOwner; MemoryContext savePortalContext; MemoryContext saveQueryContext; @@ -485,12 +525,14 @@ PortalRun(Portal portal, long count, * Set up global portal context pointers. */ saveActivePortal = ActivePortal; + saveActiveSnapshot = ActiveSnapshot; saveResourceOwner = CurrentResourceOwner; savePortalContext = PortalContext; saveQueryContext = QueryContext; PG_TRY(); { ActivePortal = portal; + ActiveSnapshot = NULL; /* will be set later */ CurrentResourceOwner = portal->resowner; PortalContext = PortalGetHeapMemory(portal); QueryContext = portal->queryContext; @@ -579,6 +621,7 @@ PortalRun(Portal portal, long count, /* Restore global vars and propagate error */ ActivePortal = saveActivePortal; + ActiveSnapshot = saveActiveSnapshot; CurrentResourceOwner = saveResourceOwner; PortalContext = savePortalContext; QueryContext = saveQueryContext; @@ -590,6 +633,7 @@ PortalRun(Portal portal, long count, MemoryContextSwitchTo(oldContext); ActivePortal = saveActivePortal; + ActiveSnapshot = saveActiveSnapshot; CurrentResourceOwner = saveResourceOwner; PortalContext = savePortalContext; QueryContext = saveQueryContext; @@ -670,6 +714,7 @@ PortalRunSelect(Portal portal, nprocessed = RunFromStore(portal, direction, count, dest); else { + ActiveSnapshot = queryDesc->snapshot; ExecutorRun(queryDesc, direction, count); nprocessed = queryDesc->estate->es_processed; } @@ -711,6 +756,7 @@ PortalRunSelect(Portal portal, nprocessed = RunFromStore(portal, direction, count, dest); else { + ActiveSnapshot = queryDesc->snapshot; ExecutorRun(queryDesc, direction, count); nprocessed = queryDesc->estate->es_processed; } @@ -834,6 +880,9 @@ PortalRunUtility(Portal portal, Query *query, * the database --- if, say, it has to update an index with * expressions that invoke user-defined functions, then it had better * have a snapshot. + * + * Note we assume that caller will take care of restoring ActiveSnapshot + * on exit/error. */ if (!(IsA(utilityStmt, TransactionStmt) || IsA(utilityStmt, LockStmt) || @@ -847,7 +896,9 @@ PortalRunUtility(Portal portal, Query *query, IsA(utilityStmt, NotifyStmt) || IsA(utilityStmt, UnlistenStmt) || IsA(utilityStmt, CheckPointStmt))) - SetQuerySnapshot(); + ActiveSnapshot = CopySnapshot(GetTransactionSnapshot()); + else + ActiveSnapshot = NULL; if (query->canSetTag) { @@ -864,6 +915,10 @@ PortalRunUtility(Portal portal, Query *query, /* Some utility statements may change context on us */ MemoryContextSwitchTo(PortalGetHeapMemory(portal)); + + if (ActiveSnapshot) + FreeSnapshot(ActiveSnapshot); + ActiveSnapshot = NULL; } /* @@ -924,15 +979,6 @@ PortalRunMulti(Portal portal, /* * process a plannable query. */ - ereport(DEBUG3, - (errmsg_internal("ProcessQuery"))); - - /* Must always set snapshot for plannable queries */ - SetQuerySnapshot(); - - /* - * execute the plan - */ if (log_executor_stats) ResetUsage(); @@ -1005,6 +1051,7 @@ PortalRunFetch(Portal portal, { long result; Portal saveActivePortal; + Snapshot saveActiveSnapshot; ResourceOwner saveResourceOwner; MemoryContext savePortalContext; MemoryContext saveQueryContext; @@ -1025,12 +1072,14 @@ PortalRunFetch(Portal portal, * Set up global portal context pointers. */ saveActivePortal = ActivePortal; + saveActiveSnapshot = ActiveSnapshot; saveResourceOwner = CurrentResourceOwner; savePortalContext = PortalContext; saveQueryContext = QueryContext; PG_TRY(); { ActivePortal = portal; + ActiveSnapshot = NULL; /* will be set later */ CurrentResourceOwner = portal->resowner; PortalContext = PortalGetHeapMemory(portal); QueryContext = portal->queryContext; @@ -1056,6 +1105,7 @@ PortalRunFetch(Portal portal, /* Restore global vars and propagate error */ ActivePortal = saveActivePortal; + ActiveSnapshot = saveActiveSnapshot; CurrentResourceOwner = saveResourceOwner; PortalContext = savePortalContext; QueryContext = saveQueryContext; @@ -1070,6 +1120,7 @@ PortalRunFetch(Portal portal, portal->status = PORTAL_READY; ActivePortal = saveActivePortal; + ActiveSnapshot = saveActiveSnapshot; CurrentResourceOwner = saveResourceOwner; PortalContext = savePortalContext; QueryContext = saveQueryContext; |