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Last week's patch for make_sort_from_pathkeys wasn't good enough: it has

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to be able to discard top-level RelabelType nodes on *both* sides of the
equivalence-class-to-target-list comparison, since make_pathkey_from_sortinfo
might either add or remove a RelabelType.  Also fix the latter to do the
removal case cleanly.  Per example from Peter.
This commit is contained in:
Tom Lane
2007-11-08 19:25:37 +00:00
parent f1528b5154
commit 1be0601681
4 changed files with 50 additions and 23 deletions
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30
src/backend/optimizer/util/tlist.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/tlist.c,v 1.74 2007/01/05 22:19:33 momjian Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/tlist.c,v 1.75 2007/11/08 19:25:37 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -44,6 +44,34 @@ tlist_member(Node *node, List *targetlist)
return NULL;
}
/*
* tlist_member_ignore_relabel
* Same as above, except that we ignore top-level RelabelType nodes
* while checking for a match. This is needed for some scenarios
* involving binary-compatible sort operations.
*/
TargetEntry *
tlist_member_ignore_relabel(Node *node, List *targetlist)
{
ListCell *temp;
while (node && IsA(node, RelabelType))
node = (Node *) ((RelabelType *) node)->arg;
foreach(temp, targetlist)
{
TargetEntry *tlentry = (TargetEntry *) lfirst(temp);
Expr *tlexpr = tlentry->expr;
while (tlexpr && IsA(tlexpr, RelabelType))
tlexpr = ((RelabelType *) tlexpr)->arg;
if (equal(node, tlexpr))
return tlentry;
}
return NULL;
}
/*
* flatten_tlist
* Create a target list that only contains unique variables.