Fix testing of parallel-safety of scan/join target.

Etsuro Fujita · Etsuro Fujita · commit b5afdde6a7bb · 2019-03-12T16:21:57.000+09:00
In commit 960df2a ("Correctly assess parallel-safety of tlists when SRFs are used."), the testing of scan/join target was done incorrectly, which caused a plan-quality problem. Backpatch through to v11 where the aforementioned commit went in, since this is a regression from v10. Author: Etsuro Fujita Reviewed-by: Robert Haas and Tom Lane Discussion: https://postgr.es/m/5C75303E.8020303@lab.ntt.co.jp
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
@@ -1993,7 +1993,7 @@ grouping_planner(PlannerInfo *root, bool inheritance_update,
 		{
 			scanjoin_target = make_group_input_target(root, final_target);
 			scanjoin_target_parallel_safe =
-				is_parallel_safe(root, (Node *) grouping_target->exprs);
+				is_parallel_safe(root, (Node *) scanjoin_target->exprs);
 		}
 		else
 		{

Original file line number	Diff line number	Diff line change
`@@ -1993,7 +1993,7 @@ grouping_planner(PlannerInfo *root, bool inheritance_update,`
`1993`	`1993`	`{`
`1994`	`1994`	`scanjoin_target = make_group_input_target(root, final_target);`
`1995`	`1995`	`scanjoin_target_parallel_safe =`
`1996`		`- is_parallel_safe(root, (Node *) grouping_target->exprs);`
	`1996`	`+ is_parallel_safe(root, (Node *) scanjoin_target->exprs);`
`1997`	`1997`	`}`
`1998`	`1998`	`else`
`1999`	`1999`	`{`