Manfred Koizar <[EMAIL PROTECTED]> writes:
> ISTM you have found a Postgres 7.3 bug.
Yeah. Actually, the planner bug has been there a long time, but it was
only latent until the parser stopped suppressing duplicate GROUP BY
items:
2002-08-18 14:46 tgl
* src/backend/parser/parse_clause.c: Remove optimization whereby
parser would make only one sort-list entry when two equal()
targetlist items were to be added to an ORDER BY or DISTINCT list.
Although indeed this would make sorting fractionally faster by
sometimes saving a comparison, it confuses the heck out of later
stages of processing, because it makes it look like the user wrote
DISTINCT ON rather than DISTINCT. Bug reported by
[EMAIL PROTECTED]
7.3 patch is attached if you need it.
regards, tom lane
*** src/backend/optimizer/plan/planner.c.orig Wed Mar 5 13:38:26 2003
--- src/backend/optimizer/plan/planner.c Thu Mar 13 11:21:16 2003
***************
*** 1498,1510 ****
* are just dummies with no extra execution cost.)
*/
List *sort_tlist = new_unsorted_tlist(subplan->targetlist);
int keyno = 0;
List *gl;
foreach(gl, groupClause)
{
GroupClause *grpcl = (GroupClause *) lfirst(gl);
! TargetEntry *te = nth(grpColIdx[keyno] - 1, sort_tlist);
Resdom *resdom = te->resdom;
/*
--- 1498,1511 ----
* are just dummies with no extra execution cost.)
*/
List *sort_tlist = new_unsorted_tlist(subplan->targetlist);
+ int grpno = 0;
int keyno = 0;
List *gl;
foreach(gl, groupClause)
{
GroupClause *grpcl = (GroupClause *) lfirst(gl);
! TargetEntry *te = nth(grpColIdx[grpno] - 1, sort_tlist);
Resdom *resdom = te->resdom;
/*
***************
*** 1518,1523 ****
--- 1519,1525 ----
resdom->reskey = ++keyno;
resdom->reskeyop = grpcl->sortop;
}
+ grpno++;
}
Assert(keyno > 0);
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