Fix an old thinko in SS_make_initplan_from_plan, which is used when optimizing

a MIN or MAX aggregate call into an indexscan: the initplan is being made at
the current query nesting level and so we shouldn't increment query_level.
Though usually harmless, this mistake could lead to bogus "plan should not
reference subplan's variable" failures on complex queries.  Per bug report
from David Sanchez i Gregori.

diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
index f041628e684cf44c0da4739d8e1c7bc769223522..fdfa2ee87b233e3653c4776af6d73962cae5266a 100644 (file)
--- a/src/backend/optimizer/plan/subselect.c
+++ b/src/backend/optimizer/plan/subselect.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.112.2.1 2006/12/06 19:40:08 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.112.2.2 2007/07/18 21:41:14 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1306,10 +1306,14 @@ SS_make_initplan_from_plan(PlannerInfo *root, Plan *plan,
        Param      *prm;
 
        /*
-        * Set up for a new level of subquery.  This is just to keep
-        * SS_finalize_plan from becoming confused.
+        * We must run SS_finalize_plan(), since that's normally done before a
+        * subplan gets put into the initplan list.  However it will try to attach
+        * any pre-existing initplans to this one, which we don't want (they are
+        * siblings not children of this initplan).  So, a quick kluge to hide
+        * them.  (This is something else that could perhaps be cleaner if we did
+        * extParam/allParam processing in setrefs.c instead of here?  See notes
+        * for materialize_finished_plan.)
         */
-       PlannerQueryLevel++;
        PlannerInitPlan = NIL;
 
        /*
@@ -1317,8 +1321,7 @@ SS_make_initplan_from_plan(PlannerInfo *root, Plan *plan,
         */
        SS_finalize_plan(plan, root->parse->rtable);
 
-       /* Return to outer subquery context */
-       PlannerQueryLevel--;
+       /* Restore outer initplan list */
        PlannerInitPlan = saved_initplan;
 
        /*

diff --git a/src/test/regress/expected/subselect.out b/src/test/regress/expected/subselect.out
index f36b5acfe8653f51d82d14c0e1ae2a28b8fa16de..bc0f991ae1e718992b411020cea59f00dacab648 100644 (file)
--- a/src/test/regress/expected/subselect.out
+++ b/src/test/regress/expected/subselect.out
@@ -386,3 +386,25 @@ select f1, ss1 as relabel from
  -2147483647 |          0
 (5 rows)
 
+--
+-- Test cases involving PARAM_EXEC parameters and min/max index optimizations.
+-- Per bug report from David Sanchez i Gregori.
+--
+select * from (
+  select max(unique1) from tenk1 as a
+  where exists (select 1 from tenk1 as b where b.thousand = a.unique2)
+) ss;
+ max  
+------
+ 9997
+(1 row)
+
+select * from (
+  select min(unique1) from tenk1 as a
+  where not exists (select 1 from tenk1 as b where b.unique2 = 10000)
+) ss;
+ min 
+-----
+   0
+(1 row)
+

diff --git a/src/test/regress/sql/subselect.sql b/src/test/regress/sql/subselect.sql
index b8cb45c6fc75d0204f6cecb68f978e0ba13edbd1..cb20721b1dee08a305671e4416ff64c70edda72b 100644 (file)
--- a/src/test/regress/sql/subselect.sql
+++ b/src/test/regress/sql/subselect.sql
@@ -236,3 +236,18 @@ select * from shipped_view;
 select f1, ss1 as relabel from
     (select *, (select sum(f1) from int4_tbl b where f1 >= a.f1) as ss1
      from int4_tbl a) ss;
+
+--
+-- Test cases involving PARAM_EXEC parameters and min/max index optimizations.
+-- Per bug report from David Sanchez i Gregori.
+--
+
+select * from (
+  select max(unique1) from tenk1 as a
+  where exists (select 1 from tenk1 as b where b.thousand = a.unique2)
+) ss;
+
+select * from (
+  select min(unique1) from tenk1 as a
+  where not exists (select 1 from tenk1 as b where b.unique2 = 10000)
+) ss;