Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commitfcba3b8

Browse files
committed
Tweak trivial_subqueryscan() to consider a SubqueryScan's targetlist
trivial if it contains either Vars referencing the corresponding subplancolumns, or Consts equaling the corresponding subplan columns. Thislets the planner eliminate the SubqueryScan in some cases generated bygenerate_setop_tlist().
1 parent88b8110 commitfcba3b8

File tree

1 file changed

+24
-8
lines changed

1 file changed

+24
-8
lines changed

‎src/backend/optimizer/plan/setrefs.c‎

Lines changed: 24 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@
99
*
1010
*
1111
* IDENTIFICATION
12-
* $PostgreSQL: pgsql/src/backend/optimizer/plan/setrefs.c,v 1.124 2006/08/12 02:52:05 tgl Exp $
12+
* $PostgreSQL: pgsql/src/backend/optimizer/plan/setrefs.c,v 1.125 2006/08/28 14:32:41 tgl Exp $
1313
*
1414
*-------------------------------------------------------------------------
1515
*/
@@ -448,16 +448,32 @@ trivial_subqueryscan(SubqueryScan *plan)
448448
{
449449
TargetEntry*ptle= (TargetEntry*)lfirst(lp);
450450
TargetEntry*ctle= (TargetEntry*)lfirst(lc);
451-
Var*var= (Var*)ptle->expr;
452451

453452
if (ptle->resjunk!=ctle->resjunk)
454453
return false;/* tlist doesn't match junk status */
455-
if (!var|| !IsA(var,Var))
456-
return false;/* tlist item not a Var */
457-
Assert(var->varno==plan->scan.scanrelid);
458-
Assert(var->varlevelsup==0);
459-
if (var->varattno!=attrno)
460-
return false;/* out of order */
454+
455+
/*
456+
* We accept either a Var referencing the corresponding element of
457+
* the subplan tlist, or a Const equaling the subplan element.
458+
* See generate_setop_tlist() for motivation.
459+
*/
460+
if (ptle->expr&&IsA(ptle->expr,Var))
461+
{
462+
Var*var= (Var*)ptle->expr;
463+
464+
Assert(var->varno==plan->scan.scanrelid);
465+
Assert(var->varlevelsup==0);
466+
if (var->varattno!=attrno)
467+
return false;/* out of order */
468+
}
469+
elseif (ptle->expr&&IsA(ptle->expr,Const))
470+
{
471+
if (!equal(ptle->expr,ctle->expr))
472+
return false;
473+
}
474+
else
475+
return false;
476+
461477
attrno++;
462478
}
463479

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp