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Fix oversight in initial implementation of PORTAL_ONE_RETURNING mode: we

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cannot assume that there's exactly one Query in the Portal, as we can for
ONE_SELECT mode, because non-SELECT queries might have extra queries added
during rule rewrites.  Fix things up so that we'll use ONE_RETURNING mode
when a Portal contains one primary (canSetTag) query and that query has
a RETURNING list.  This appears to be a second showstopper reason for running
the Portal to completion before we start to hand anything back --- we want
to be sure that the rule-added queries get run too.
This commit is contained in:
Tom Lane
2006-08-14 22:57:15 +00:00
parent 3d1e01caa4
commit 65b2f93b58
5 changed files with 136 additions and 62 deletions
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62
src/backend/tcop/pquery.c
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@ -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;