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We have to return dummy tuple for empty targetlist!

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Try select t1.x from t1, t2 where t1.y = 1 and t2.y = 1
- t2 scan target list will be empty and so no one tuple
will be returned...
This commit is contained in:
Vadim B. Mikheev 1999-03-10 12:16:09 +00:00
parent f8f0efb43d
commit 2a76aa23e0
1 changed files with 8 additions and 9 deletions
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17
src/backend/executor/execQual.c
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@ -7,7 +7,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.46 1999/02/23 07:33:44 thomas Exp $ * $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.47 1999/03/10 12:16:09 vadim Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -1474,10 +1474,15 @@ ExecTargetList(List *targetlist,
* is this a new phenomenon? it might cause bogus behavior * is this a new phenomenon? it might cause bogus behavior
* if we try to free this tuple later!! I put a hook in * if we try to free this tuple later!! I put a hook in
* ExecProject to watch out for this case -mer 24 Aug 1992 * ExecProject to watch out for this case -mer 24 Aug 1992
*
* We must return dummy tuple!!! Try
* select t1.x from t1, t2 where t1.y = 1 and t2.y = 1
* - t2 scan target list will be empty and so no one tuple
* will be returned! But Mer was right - dummy tuple
* must be palloced... - vadim 03/01/1999
*/ */
CXT1_printf("ExecTargetList: context is %d\n", CurrentMemoryContext);
*isDone = true; *isDone = true;
return (HeapTuple) true; return (HeapTuple) palloc(1);
} }
/* /*
@ -1640,12 +1645,6 @@ ExecProject(ProjectionInfo *projInfo, bool *isDone)
tupValue = projInfo->pi_tupValue; tupValue = projInfo->pi_tupValue;
econtext = projInfo->pi_exprContext; econtext = projInfo->pi_exprContext;
if (targetlist == NIL)
{
*isDone = true;
return (TupleTableSlot *) NULL;
}
/* /*
* form a new (result) tuple * form a new (result) tuple
*/ */