v7-0003-Possible-additional-checks.patch

From f2c2e5d64130a876dde539d09d049508820c5063 Mon Sep 17 00:00:00 2001
From: jcoleman <jtc331@gmail.com>
Date: Wed, 18 Jan 2023 20:49:42 -0500
Subject: [PATCH v7 3/4] Possible additional checks

---
 src/backend/optimizer/path/allpaths.c | 32 ++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 6 deletions(-)

diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index f93c6927b7..58433b762e 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -3019,11 +3019,19 @@ generate_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows)
 	ListCell   *lc;
 	double		rows;
 	double	   *rowsp = NULL;
+	Relids		required_outer = rel->lateral_relids;
 
 	/* If there are no partial paths, there's nothing to do here. */
 	if (rel->partial_pathlist == NIL)
 		return;
 
+	/*
+	 * Delay gather path creation until the level in the join tree where all
+	 * params used in a worker are generated within that worker.
+	 */
+	if (!bms_is_subset(required_outer, rel->relids))
+		return;
+
 	/* Should we override the rel's rowcount estimate? */
 	if (override_rows)
 		rowsp = &rows;
@@ -3034,12 +3042,16 @@ generate_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows)
 	 * of partial_pathlist because of the way add_partial_path works.
 	 */
 	cheapest_partial_path = linitial(rel->partial_pathlist);
-	rows =
-		cheapest_partial_path->rows * cheapest_partial_path->parallel_workers;
-	simple_gather_path = (Path *)
-		create_gather_path(root, rel, cheapest_partial_path, rel->reltarget,
-						   rel->lateral_relids, rowsp);
-	add_path(rel, simple_gather_path);
+	if (cheapest_partial_path->param_info == NULL ||
+			bms_is_subset(cheapest_partial_path->param_info->ppi_req_outer, rel->relids))
+	{
+		rows =
+			cheapest_partial_path->rows * cheapest_partial_path->parallel_workers;
+		simple_gather_path = (Path *)
+			create_gather_path(root, rel, cheapest_partial_path, rel->reltarget,
+							   rel->lateral_relids, rowsp);
+		add_path(rel, simple_gather_path);
+	}
 
 	/*
 	 * For each useful ordering, we can consider an order-preserving Gather
@@ -3053,6 +3065,10 @@ generate_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_rows)
 		if (subpath->pathkeys == NIL)
 			continue;
 
+		if (subpath->param_info != NULL &&
+			!bms_is_subset(subpath->param_info->ppi_req_outer, rel->relids))
+			continue;
+
 		rows = subpath->rows * subpath->parallel_workers;
 		path = create_gather_merge_path(root, rel, subpath, rel->reltarget,
 										subpath->pathkeys, rel->lateral_relids, rowsp);
@@ -3226,6 +3242,10 @@ generate_useful_gather_paths(PlannerInfo *root, RelOptInfo *rel, bool override_r
 				(presorted_keys == 0 || !enable_incremental_sort))
 				continue;
 
+			if (subpath->param_info != NULL &&
+				!bms_is_subset(subpath->param_info->ppi_req_outer, rel->relids))
+				continue;
+
 			/*
 			 * Consider regular sort for any path that's not presorted or if
 			 * incremental sort is disabled.  We've no need to consider both
-- 
2.32.1 (Apple Git-133)