diff options
Diffstat (limited to 'src/backend/tcop/pquery.c')
| -rw-r--r-- | src/backend/tcop/pquery.c | 62 |
1 files changed, 46 insertions, 16 deletions
diff --git a/src/backend/tcop/pquery.c b/src/backend/tcop/pquery.c index 2d12b0e7c4f..3ede40570ab 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 1.106 2006/08/12 02:52:05 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.107 2006/08/14 22:57:15 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -213,30 +213,59 @@ ProcessQuery(Query *parsetree, PortalStrategy ChoosePortalStrategy(List *parseTrees) { - PortalStrategy strategy; - - strategy = PORTAL_MULTI_QUERY; /* default assumption */ + int nSetTag; + ListCell *lc; + /* + * PORTAL_ONE_SELECT and PORTAL_UTIL_SELECT need only consider the + * single-Query-struct case, since there are no rewrite rules that + * can add auxiliary queries to a SELECT or a utility command. + */ if (list_length(parseTrees) == 1) { Query *query = (Query *) linitial(parseTrees); + Assert(IsA(query, Query)); if (query->canSetTag) { if (query->commandType == CMD_SELECT && query->into == NULL) - strategy = PORTAL_ONE_SELECT; - else if (query->returningList != NIL) - strategy = PORTAL_ONE_RETURNING; - else if (query->commandType == CMD_UTILITY && - query->utilityStmt != NULL) + return PORTAL_ONE_SELECT; + if (query->commandType == CMD_UTILITY && + query->utilityStmt != NULL) { if (UtilityReturnsTuples(query->utilityStmt)) - strategy = PORTAL_UTIL_SELECT; + return PORTAL_UTIL_SELECT; + /* it can't be ONE_RETURNING, so give up */ + return PORTAL_MULTI_QUERY; } } } - return strategy; + + /* + * PORTAL_ONE_RETURNING has to allow auxiliary queries added by rewrite. + * Choose PORTAL_ONE_RETURNING if there is exactly one canSetTag query + * and it has a RETURNING list. + */ + nSetTag = 0; + foreach(lc, parseTrees) + { + Query *query = (Query *) lfirst(lc); + + Assert(IsA(query, Query)); + if (query->canSetTag) + { + if (++nSetTag > 1) + return PORTAL_MULTI_QUERY; /* no need to look further */ + if (query->returningList == NIL) + return PORTAL_MULTI_QUERY; /* no need to look further */ + } + } + if (nSetTag == 1) + return PORTAL_ONE_RETURNING; + + /* Else, it's the general case... */ + return PORTAL_MULTI_QUERY; } /* @@ -255,7 +284,7 @@ FetchPortalTargetList(Portal portal) if (portal->strategy == PORTAL_ONE_SELECT) return ((Query *) linitial(portal->parseTrees))->targetList; if (portal->strategy == PORTAL_ONE_RETURNING) - return ((Query *) linitial(portal->parseTrees))->returningList; + return (PortalGetPrimaryQuery(portal))->returningList; if (portal->strategy == PORTAL_UTIL_SELECT) { Node *utilityStmt; @@ -422,7 +451,7 @@ PortalStart(Portal portal, ParamListInfo params, Snapshot snapshot) * the portal. We do need to set up the result tupdesc. */ portal->tupDesc = - ExecCleanTypeFromTL(((Query *) linitial(portal->parseTrees))->returningList, false); + ExecCleanTypeFromTL((PortalGetPrimaryQuery(portal))->returningList, false); /* * Reset cursor position data to "start of query" @@ -894,10 +923,11 @@ FillPortalStore(Portal portal) { case PORTAL_ONE_RETURNING: /* - * We run the query just as if it were in a MULTI portal, - * but send the output to the tuplestore. + * Run the portal to completion just as for the default MULTI_QUERY + * case, but send the primary query's output to the tuplestore. + * Auxiliary query outputs are discarded. */ - PortalRunMulti(portal, treceiver, treceiver, completionTag); + PortalRunMulti(portal, treceiver, None_Receiver, completionTag); /* Override default completion tag with actual command result */ portal->commandTag = pstrdup(completionTag); break; |