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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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13
src/backend/optimizer/path/pathkeys.c
View File

@ -11,7 +11,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.87 2007/11/02 18:54:15 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.88 2007/11/08 19:25:37 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -292,13 +292,14 @@ make_pathkey_from_sortinfo(PlannerInfo *root,
if (exprType((Node *) expr) != opcintype &&
!IsPolymorphicType(opcintype))
{
/* Strip any existing RelabelType, and add a new one */
/* Strip any existing RelabelType, and add a new one if needed */
while (expr && IsA(expr, RelabelType))
expr = (Expr *) ((RelabelType *) expr)->arg;
expr = (Expr *) makeRelabelType(expr,
opcintype,
-1,
COERCE_DONTCARE);
if (exprType((Node *) expr) != opcintype)
expr = (Expr *) makeRelabelType(expr,
opcintype,
-1,
COERCE_DONTCARE);
}
/* Now find or create a matching EquivalenceClass */

27
src/backend/optimizer/plan/createplan.c
View File

@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.232 2007/11/02 18:54:15 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.233 2007/11/08 19:25:37 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -2738,7 +2738,7 @@ make_sort_from_pathkeys(PlannerInfo *root, Plan *lefttree, List *pathkeys,
/*
* We can sort by any non-constant expression listed in the pathkey's
* EquivalenceClass. For now, we take the first one that corresponds
* to an available Var in the tlist. If there isn't any, use the first
* to an available item in the tlist. If there isn't any, use the first
* one that is an expression in the input's vars. (The non-const
* restriction only matters if the EC is below_outer_join; but if it
* isn't, it won't contain consts anyway, else we'd have discarded
@ -2766,24 +2766,21 @@ make_sort_from_pathkeys(PlannerInfo *root, Plan *lefttree, List *pathkeys,
/*
* We can also use it if the pathkey expression is a relabel
* of the tlist entry. This is needed for binary-compatible
* cases (cf. make_pathkey_from_sortinfo).
* of the tlist entry, or vice versa. This is needed for
* binary-compatible cases (cf. make_pathkey_from_sortinfo).
* We prefer an exact match, though, so we do the basic
* search first.
*/
if (IsA(em->em_expr, RelabelType))
tle = tlist_member_ignore_relabel((Node *) em->em_expr, tlist);
if (tle)
{
Expr *rtarg = ((RelabelType *) em->em_expr)->arg;
tle = tlist_member((Node *) rtarg, tlist);
if (tle)
{
pk_datatype = em->em_datatype;
break; /* found expr already in tlist */
}
pk_datatype = em->em_datatype;
break; /* found expr already in tlist */
}
}
if (!tle)
{
/* No matching Var; look for a computable expression */
/* No matching tlist item; look for a computable expression */
Expr *sortexpr = NULL;
foreach(j, pathkey->pk_eclass->ec_members)
@ -2798,7 +2795,7 @@ make_sort_from_pathkeys(PlannerInfo *root, Plan *lefttree, List *pathkeys,
exprvars = pull_var_clause((Node *) sortexpr, false);
foreach(k, exprvars)
{
if (!tlist_member(lfirst(k), tlist))
if (!tlist_member_ignore_relabel(lfirst(k), tlist))
break;
}
list_free(exprvars);

30
src/backend/optimizer/util/tlist.c
View File

@ -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.

3
src/include/optimizer/tlist.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/optimizer/tlist.h,v 1.45 2007/01/05 22:19:56 momjian Exp $
* $PostgreSQL: pgsql/src/include/optimizer/tlist.h,v 1.46 2007/11/08 19:25:37 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -18,6 +18,7 @@
extern TargetEntry *tlist_member(Node *node, List *targetlist);
extern TargetEntry *tlist_member_ignore_relabel(Node *node, List *targetlist);
extern List *flatten_tlist(List *tlist);
extern List *add_to_flat_tlist(List *tlist, List *vars);