mirrors/postgres
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Current implementation of FOR UPDATE has no hope of working correctly

Browse Source 
for relations on the nullable side of an OUTER JOIN.  For now I think
we'd better refuse such queries.
This commit is contained in:
Tom Lane 2001-05-14 20:25:00 +00:00
parent 7d802e07a7
commit 248182560c
1 changed files with 18 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
src/backend/optimizer/plan/initsplan.c
View File

@ -8,7 +8,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/initsplan.c,v 1.60 2001/05/07 00:43:21 tgl Exp $ * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/initsplan.c,v 1.61 2001/05/14 20:25:00 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -298,7 +298,8 @@ mark_baserels_for_outer_join(Query *root, Relids rels, Relids outerrels)
foreach(relid, rels) foreach(relid, rels)
{ {
RelOptInfo *rel = get_base_rel(root, lfirsti(relid)); int relno = lfirsti(relid);
RelOptInfo *rel = get_base_rel(root, relno);
/* /*
* Since we do this bottom-up, any outer-rels previously marked * Since we do this bottom-up, any outer-rels previously marked
@ -306,6 +307,21 @@ mark_baserels_for_outer_join(Query *root, Relids rels, Relids outerrels)
*/ */
Assert(is_subseti(rel->outerjoinset, outerrels)); Assert(is_subseti(rel->outerjoinset, outerrels));
/*
* Presently the executor cannot support FOR UPDATE marking of
* rels appearing on the nullable side of an outer join.
* (It's somewhat unclear what that would mean, anyway: what should
* we mark when a result row is generated from no element of the
* nullable relation?) So, complain if target rel is FOR UPDATE.
* It's sufficient to make this check once per rel, so do it only
* if rel wasn't already known nullable.
*/
if (rel->outerjoinset == NIL)
{
if (intMember(relno, root->rowMarks))
elog(ERROR, "SELECT FOR UPDATE cannot be applied to the nullable side of an OUTER JOIN");
}
rel->outerjoinset = outerrels; rel->outerjoinset = outerrels;
} }
} }