3 files changed, 53 insertions, 2 deletions

diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 1c792a00eb2..ea4e683abb0 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -2179,6 +2179,28 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
 				 create_subqueryscan_path(root, rel, subpath,
 										  pathkeys, required_outer));
 	}
+
+	/* If consider_parallel is false, there should be no partial paths. */
+	Assert(sub_final_rel->consider_parallel ||
+		   sub_final_rel->partial_pathlist == NIL);
+
+	/* Same for partial paths. */
+	foreach(lc, sub_final_rel->partial_pathlist)
+	{
+		Path	   *subpath = (Path *) lfirst(lc);
+		List	   *pathkeys;
+
+		/* Convert subpath's pathkeys to outer representation */
+		pathkeys = convert_subquery_pathkeys(root,
+											 rel,
+											 subpath->pathkeys,
+											 make_tlist_from_pathtarget(subpath->pathtarget));
+
+		/* Generate outer path using this subpath */
+		add_partial_path(rel, (Path *)
+						 create_subqueryscan_path(root, rel, subpath,
+												  pathkeys, required_outer));
+	}
 }
 
 /*
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 24e6c463961..66e7e7badcf 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -2195,6 +2195,22 @@ grouping_planner(PlannerInfo *root, bool inheritance_update,
 	}
 
 	/*
+	 * Generate partial paths for final_rel, too, if outer query levels might
+	 * be able to make use of them.
+	 */
+	if (final_rel->consider_parallel && root->query_level > 1 &&
+		!limit_needed(parse))
+	{
+		Assert(!parse->rowMarks && parse->commandType == CMD_SELECT);
+		foreach(lc, current_rel->partial_pathlist)
+		{
+			Path	   *partial_path = (Path *) lfirst(lc);
+
+			add_partial_path(final_rel, partial_path);
+		}
+	}
+
+	/*
 	 * If there is an FDW that's responsible for all baserels of the query,
 	 * let it consider adding ForeignPaths.
 	 */
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
index dc86dd5a0b6..83008d76619 100644
--- a/src/backend/optimizer/plan/subselect.c
+++ b/src/backend/optimizer/plan/subselect.c
@@ -2202,6 +2202,13 @@ SS_charge_for_initplans(PlannerInfo *root, RelOptInfo *final_rel)
 		path->parallel_safe = false;
 	}
 
+	/*
+	 * Forget about any partial paths and clear consider_parallel, too;
+	 * they're not usable if we attached an initPlan.
+	 */
+	final_rel->partial_pathlist = NIL;
+	final_rel->consider_parallel = false;
+
 	/* We needn't do set_cheapest() here, caller will do it */
 }
 
@@ -2407,10 +2414,16 @@ finalize_plan(PlannerInfo *root, Plan *plan,
 			{
 				SubqueryScan *sscan = (SubqueryScan *) plan;
 				RelOptInfo *rel;
+				Bitmapset  *subquery_params;
 
-				/* We must run SS_finalize_plan on the subquery */
+				/* We must run finalize_plan on the subquery */
 				rel = find_base_rel(root, sscan->scan.scanrelid);
-				SS_finalize_plan(rel->subroot, sscan->subplan);
+				subquery_params = rel->subroot->outer_params;
+				if (gather_param >= 0)
+					subquery_params = bms_add_member(bms_copy(subquery_params),
+													 gather_param);
+				finalize_plan(rel->subroot, sscan->subplan, gather_param,
+							  subquery_params, NULL);
 
 				/* Now we can add its extParams to the parent's params */
 				context.paramids = bms_add_members(context.paramids,