Repair bug reported by Laurent Perez: bad plan generated when UPDATE or

DELETE of an inheritance tree references another inherited relation.
This bug has been latent since 7.1; I'm still not quite sure why 7.1 and
7.2 don't manifest it (at least, they don't crash on a simple test case).

diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 76862c769cb78eb9f84b6deb036f6714cbccd395..c597e44f1d46b7b8ec0322dead4122c0d23dae17 100644 (file)
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.148 2003/02/15 21:39:58 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.149 2003/03/05 18:38:14 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -443,6 +443,7 @@ inheritance_planner(Query *parse, List *inheritlist)
 {
    int         parentRTindex = parse->resultRelation;
    Oid         parentOID = getrelid(parentRTindex, parse->rtable);
+   int         mainrtlength = length(parse->rtable);
    List       *subplans = NIL;
    List       *tlist = NIL;
    List       *l;
@@ -451,6 +452,7 @@ inheritance_planner(Query *parse, List *inheritlist)
    {
        int         childRTindex = lfirsti(l);
        Oid         childOID = getrelid(childRTindex, parse->rtable);
+       int         subrtlength;
        Query      *subquery;
        Plan       *subplan;
 
@@ -461,6 +463,24 @@ inheritance_planner(Query *parse, List *inheritlist)
        /* Generate plan */
        subplan = grouping_planner(subquery, 0.0 /* retrieve all tuples */ );
        subplans = lappend(subplans, subplan);
+       /*
+        * It's possible that additional RTEs got added to the rangetable
+        * due to expansion of inherited source tables (see allpaths.c).
+        * If so, we must copy 'em back to the main parse tree's rtable.
+        *
+        * XXX my goodness this is ugly.  Really need to think about ways
+        * to rein in planner's habit of scribbling on its input.
+        */
+       subrtlength = length(subquery->rtable);
+       if (subrtlength > mainrtlength)
+       {
+           List   *subrt = subquery->rtable;
+
+           while (mainrtlength-- > 0) /* wish we had nthcdr() */
+               subrt = lnext(subrt);
+           parse->rtable = nconc(parse->rtable, subrt);
+           mainrtlength = subrtlength;
+       }
        /* Save preprocessed tlist from first rel for use in Append */
        if (tlist == NIL)
            tlist = subplan->targetlist;