Keep the planner from failing on "WHERE false AND something IN (SELECT ...)".

eval_const_expressions simplifies this to just "WHERE false", but we have
already done pull_up_IN_clauses so the IN join will be done, or at least
planned, anyway.  The trouble case comes when the sub-SELECT is itself a join
and we decide to implement the IN by unique-ifying the sub-SELECT outputs:
with no remaining reference to the output Vars in WHERE, we won't have
propagated the Vars up to the upper join point, leading to "variable not found
in subplan target lists" error.  Fix by adding an extra scan of in_info_list
and forcing all Vars mentioned therein to be propagated up to the IN join
point.  Per bug report from Miroslav Sulc.

diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index f55adc8591507eb0f27d43bc8ab6c12d5d06fd50..b6993f64c05edaa61c8d78d221472e6bf7e68d37 100644 (file)
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.104.4.1 2005/09/28 21:17:23 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.104.4.2 2007/10/04 20:45:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -126,6 +126,40 @@ build_base_rel_tlists(Query *root, List *final_tlist)
        }
 }
 
+/*
+ * add_IN_vars_to_tlists
+ *       Add targetlist entries for each var needed in InClauseInfo entries
+ *       to the appropriate base relations.
+ *
+ * Normally this is a waste of time because scanning of the WHERE clause
+ * will have added them.  But it is possible that eval_const_expressions()
+ * simplified away all references to the vars after the InClauseInfos were
+ * made.  We need the IN's righthand-side vars to be available at the join
+ * anyway, in case we try to unique-ify the subselect's outputs.  (The only
+ * known case that provokes this is "WHERE false AND foo IN (SELECT ...)".
+ * We don't try to be very smart about such cases, just correct.)
+ */
+void
+add_IN_vars_to_tlists(Query *root)
+{
+       ListCell   *l;
+
+       foreach(l, root->in_info_list)
+       {
+               InClauseInfo *ininfo = (InClauseInfo *) lfirst(l);
+               List       *in_vars;
+
+               in_vars = pull_var_clause((Node *) ininfo->sub_targetlist, false);
+               if (in_vars != NIL)
+               {
+                       add_vars_to_targetlist(root, in_vars,
+                                                                  bms_union(ininfo->lefthand,
+                                                                                        ininfo->righthand));
+                       list_free(in_vars);
+               }
+       }
+}
+
 /*
  * add_vars_to_targetlist
  *       For each variable appearing in the list, add it to the owning

diff --git a/src/backend/optimizer/plan/planmain.c b/src/backend/optimizer/plan/planmain.c
index 7ad11ee3226e9b188d2a0cf2dbe70ba911787549..b7898ad1759b65fb57838440409a3bd29aa5842d 100644 (file)
--- a/src/backend/optimizer/plan/planmain.c
+++ b/src/backend/optimizer/plan/planmain.c
@@ -14,7 +14,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/optimizer/plan/planmain.c,v 1.81.4.1 2005/09/28 21:17:23 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/optimizer/plan/planmain.c,v 1.81.4.2 2007/10/04 20:45:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -135,6 +135,13 @@ query_planner(Query *root, List *tlist, double tuple_fraction,
 
        (void) distribute_quals_to_rels(root, (Node *) root->jointree, false);
 
+       /*
+        * Vars mentioned in InClauseInfo items also have to be added to baserel
+        * targetlists.  Nearly always, they'd have got there from the original
+        * WHERE qual, but in corner cases maybe not.
+        */
+       add_IN_vars_to_tlists(root);
+
        /*
         * Use the completed lists of equijoined keys to deduce any implied
         * but unstated equalities (for example, A=B and B=C imply A=C).

diff --git a/src/include/optimizer/planmain.h b/src/include/optimizer/planmain.h
index 9c359b499f61bbf1c7f2c4342008f4f20545a19d..0a0d3fc95cf759cf58d96e617dee2705cd4f4a04 100644 (file)
--- a/src/include/optimizer/planmain.h
+++ b/src/include/optimizer/planmain.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/planmain.h,v 1.79.4.1 2005/09/28 21:17:24 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/planmain.h,v 1.79.4.2 2007/10/04 20:45:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -57,6 +57,7 @@ extern bool is_projection_capable_plan(Plan *plan);
  */
 extern void add_base_rels_to_query(Query *root, Node *jtnode);
 extern void build_base_rel_tlists(Query *root, List *final_tlist);
+extern void add_IN_vars_to_tlists(Query *root);
 extern Relids distribute_quals_to_rels(Query *root, Node *jtnode,
                                                                           bool below_outer_join);
 extern void process_implied_equality(Query *root,