Fix placement of initPlans when forcibly materializing a subplan.

If we forcibly place a Material node atop a finished subplan, we need
to move any initPlans attached to the subplan up to the Material node,
in order to keep SS_finalize_plan() happy.  I'd figured this out in
commit 7b67a0a49 for the case of materializing a cursor plan, but out of
an abundance of caution, I put the initPlan movement hack at the call
site for that case, rather than inside materialize_finished_plan().
That was the wrong thing, because it turns out to also be necessary for
the only other caller of materialize_finished_plan(), ie subselect.c.
We lacked any test cases that exposed the mistake, but bug#14524 from
Wei Congrui shows that it's possible to get an initPlan reference into
the top tlist in that case too, and then SS_finalize_plan() complains.
Hence, move the hack into materialize_finished_plan().

In HEAD, also relocate some recently-added tests in subselect.sql, which
I'd unthinkingly dropped into the middle of a sequence of related tests.

Report: https://postgr.es/m/20170202060020.1400.89021@wrigleys.postgresql.org

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 47158f646802aaeab776192b98329a940bbdbea3..427eedea91e0336ff6a5740677d7674684b76bfe 100644 (file)
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -5629,6 +5629,16 @@ materialize_finished_plan(Plan *subplan)
 
        matplan = (Plan *) make_material(subplan);
 
+       /*
+        * XXX horrid kluge: if there are any initPlans attached to the subplan,
+        * move them up to the Material node, which is now effectively the top
+        * plan node in its query level.  This prevents failure in
+        * SS_finalize_plan(), which see for comments.  We don't bother adjusting
+        * the subplan's cost estimate for this.
+        */
+       matplan->initPlan = subplan->initPlan;
+       subplan->initPlan = NIL;
+
        /* Set cost data */
        cost_material(&matpath,
                                  subplan->startup_cost,

diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index d9e2b45065efadf4bd5bfa5e16d12b6959dde9f8..23a9e7ba4659d53623a7a8b74ac15d2b8e1100ab 100644 (file)
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -305,21 +305,7 @@ standard_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
        if (cursorOptions & CURSOR_OPT_SCROLL)
        {
                if (!ExecSupportsBackwardScan(top_plan))
-               {
-                       Plan       *sub_plan = top_plan;
-
-                       top_plan = materialize_finished_plan(sub_plan);
-
-                       /*
-                        * XXX horrid kluge: if there are any initPlans attached to the
-                        * formerly-top plan node, move them up to the Material node. This
-                        * prevents failure in SS_finalize_plan, which see for comments.
-                        * We don't bother adjusting the sub_plan's cost estimate for
-                        * this.
-                        */
-                       top_plan->initPlan = sub_plan->initPlan;
-                       sub_plan->initPlan = NIL;
-               }
+                       top_plan = materialize_finished_plan(top_plan);
        }
 
        /*

diff --git a/src/test/regress/expected/subselect.out b/src/test/regress/expected/subselect.out
index 0fc93d9d7267e40ceef81da6a0d657649a8a6782..21fbbb8e2227f7761ed81c9d93787ccbaa60af18 100644 (file)
--- a/src/test/regress/expected/subselect.out
+++ b/src/test/regress/expected/subselect.out
@@ -221,6 +221,29 @@ from int8_tbl group by q1 order by q1;
  4567890123456789 |      0.6
 (2 rows)
 
+-- check materialization of an initplan reference (bug #14524)
+explain (verbose, costs off)
+select 1 = all (select (select 1));
+            QUERY PLAN             
+-----------------------------------
+ Result
+   Output: (SubPlan 2)
+   SubPlan 2
+     ->  Materialize
+           Output: ($0)
+           InitPlan 1 (returns $0)
+             ->  Result
+                   Output: 1
+           ->  Result
+                 Output: $0
+(10 rows)
+
+select 1 = all (select (select 1));
+ ?column? 
+----------
+ t
+(1 row)
+
 --
 -- Check EXISTS simplification with LIMIT
 --

diff --git a/src/test/regress/sql/subselect.sql b/src/test/regress/sql/subselect.sql
index 2991223089115546c6882ddf3d1712b22f676a33..6e81ffe13f32207de73a18ac74a035cf36af3021 100644 (file)
--- a/src/test/regress/sql/subselect.sql
+++ b/src/test/regress/sql/subselect.sql
@@ -92,6 +92,11 @@ SELECT '' AS eight, ss.f1 AS "Correlated Field", ss.f3 AS "Second Field"
 select q1, float8(count(*)) / (select count(*) from int8_tbl)
 from int8_tbl group by q1 order by q1;
 
+-- check materialization of an initplan reference (bug #14524)
+explain (verbose, costs off)
+select 1 = all (select (select 1));
+select 1 = all (select (select 1));
+
 --
 -- Check EXISTS simplification with LIMIT
 --