Fix more problems with rewriter failing to set Query.hasSubLinks when inserting

a SubLink expression into a rule query.  We missed cases where the original
query contained a sub-SELECT in a function in FROM, a multi-row VALUES list,
or a RETURNING list.  Per bug #4434 from Dean Rasheed and subsequent
investigation.

Back-patch to 8.1; older releases don't have the issue because they didn't
try to be smart about setting hasSubLinks only when needed.

diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index bf244b7e63a4babf41005a3678e3fd4b02a5525a..377dffaf435b72bac093a594c9aea0bc87a670ca 100644 (file)
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.158.2.3 2007/03/01 18:50:42 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.158.2.4 2008/09/24 16:53:07 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -334,6 +334,33 @@ rewriteRuleAction(Query *parsetree,
    sub_action->rtable = list_concat((List *) copyObject(parsetree->rtable),
                                     sub_action->rtable);
 
+   /*
+    * There could have been some SubLinks in parsetree's rtable, in which
+    * case we'd better mark the sub_action correctly.
+    */
+   if (parsetree->hasSubLinks && !sub_action->hasSubLinks)
+   {
+       ListCell   *lc;
+
+       foreach(lc, parsetree->rtable)
+       {
+           RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
+
+           switch (rte->rtekind)
+           {
+               case RTE_FUNCTION:
+                   sub_action->hasSubLinks =
+                       checkExprHasSubLink(rte->funcexpr);
+                   break;
+               default:
+                   /* other RTE types don't contain bare expressions */
+                   break;
+           }
+           if (sub_action->hasSubLinks)
+               break;      /* no need to keep scanning rtable */
+       }
+   }
+
    /*
     * Each rule action's jointree should be the main parsetree's jointree
     * plus that rule's jointree, but usually *without* the original rtindex