Restore current hint state when returned from non-hinted query planning.

If no hint is given for the current level query, pg_hint_plan_planner
calls the next level of planner after erasing the
current_hint_state. But it forgot to restore the state before the
planning of the rest part of the current-level query.  It is
(a-kind-of) broken by the commit d422966 but overlooked as an
inevitable side-effect of the fix.  Get back the behavior by restoring
current_hint_state after returned from the lower level planner with
unhinted query.

Issue: https://github.com/ossc-db/pg_hint_plan/issues/30
Reported-by: higuchi-daisuke

diff --git a/expected/ut-A.out b/expected/ut-A.out
index b3a1870..389c908 100644 (file)
--- a/expected/ut-A.out
+++ b/expected/ut-A.out
@@ -4198,6 +4198,9 @@ BEGIN
     RETURN new_cnt;
 END;
 $$ LANGUAGE plpgsql IMMUTABLE;
+-- The function called at the bottom desn't use a hint, the immediate
+-- caller level should restore its own hint. So, the first LOG from
+-- pg_hint_plan should use the IndexScan(t_1) hint
 EXPLAIN (COSTS false) SELECT nested_planner(5) FROM s1.t1 t_1 ORDER BY t_1.c1;
 NOTICE:  nested_planner(5)
 NOTICE:  nested_planner(4)
@@ -4205,7 +4208,12 @@ NOTICE:  nested_planner(3)
 NOTICE:  nested_planner(2)
 NOTICE:  nested_planner(1)
 LOG:  pg_hint_plan:
-no hint
+used hint:
+IndexScan(t_1)
+not used hint:
+duplication hint:
+error hint:
+
 LOG:  pg_hint_plan:
 used hint:
 IndexScan(t_1)
@@ -4232,7 +4240,9 @@ error hint:
  Index Only Scan using t1_i1 on t1 t_1
 (1 row)
 
-/*+SeqScan(t_2)*/
+-- The top level uses SeqScan(t_1), but the function should use only
+-- the hint in the function.
+/*+SeqScan(t_1) SeqScan(t_2)*/
 EXPLAIN (COSTS false) SELECT nested_planner(5) FROM s1.t1 t_1 ORDER BY t_1.c1;
 NOTICE:  nested_planner(5)
 NOTICE:  nested_planner(4)
@@ -4269,15 +4279,18 @@ error hint:
 
 LOG:  pg_hint_plan:
 used hint:
+SeqScan(t_1)
 not used hint:
 SeqScan(t_2)
 duplication hint:
 error hint:
 
-              QUERY PLAN               
----------------------------------------
- Index Only Scan using t1_i1 on t1 t_1
-(1 row)
+        QUERY PLAN        
+--------------------------
+ Sort
+   Sort Key: c1
+   ->  Seq Scan on t1 t_1
+(3 rows)
 
 ----
 ---- No. A-13-4 output of debugging log on hint status

diff --git a/pg_hint_plan.c b/pg_hint_plan.c
index b2fca4f..cac8815 100644 (file)
--- a/pg_hint_plan.c
+++ b/pg_hint_plan.c
@@ -3205,9 +3205,15 @@ standard_planner_proc:
        }
        current_hint_state = NULL;
        if (prev_planner)
-               return (*prev_planner) (parse, cursorOptions, boundParams);
+               result =  (*prev_planner) (parse, cursorOptions, boundParams);
        else
-               return standard_planner(parse, cursorOptions, boundParams);
+               result = standard_planner(parse, cursorOptions, boundParams);
+
+       /* The upper-level planner still needs the current hint state */
+       if (HintStateStack != NIL)
+               current_hint_state = (HintState *) lfirst(list_head(HintStateStack));
+
+       return result;
 }
 
 /*

diff --git a/sql/ut-A.sql b/sql/ut-A.sql
index 38cecb7..7968518 100644 (file)
--- a/sql/ut-A.sql
+++ b/sql/ut-A.sql
@@ -1137,8 +1137,14 @@ BEGIN
 END;
 $$ LANGUAGE plpgsql IMMUTABLE;
 
+-- The function called at the bottom desn't use a hint, the immediate
+-- caller level should restore its own hint. So, the first LOG from
+-- pg_hint_plan should use the IndexScan(t_1) hint
 EXPLAIN (COSTS false) SELECT nested_planner(5) FROM s1.t1 t_1 ORDER BY t_1.c1;
-/*+SeqScan(t_2)*/
+
+-- The top level uses SeqScan(t_1), but the function should use only
+-- the hint in the function.
+/*+SeqScan(t_1) SeqScan(t_2)*/
 EXPLAIN (COSTS false) SELECT nested_planner(5) FROM s1.t1 t_1 ORDER BY t_1.c1;
 
 ----