v4-0001-Correctly-set-userid-of-subquery-rel-s-child-rels.patch

From 616c84c79d85eb2f20858de4cfc43932dd319295 Mon Sep 17 00:00:00 2001
From: amitlan <amitlangote09@gmail.com>
Date: Wed, 18 Jan 2023 16:49:49 +0900
Subject: [PATCH v4] Correctly set userid of subquery rel's child rels

For a RTE_SUBQUERY parent baserel's child relation that itself is a
RTE_RELATION rel, build_simple_rel() should explicitly look up the
latter's RTEPermissionInfo instead of copying the parent rel's
userid, which would be 0 given that it's a subquery rel.
---
 src/backend/optimizer/util/relnode.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c
index a70a16238a..6c4550b90f 100644
--- a/src/backend/optimizer/util/relnode.c
+++ b/src/backend/optimizer/util/relnode.c
@@ -233,12 +233,22 @@ build_simple_rel(PlannerInfo *root, int relid, RelOptInfo *parent)
 	rel->serverid = InvalidOid;
 	if (rte->rtekind == RTE_RELATION)
 	{
+		Assert(parent == NULL ||
+			   parent->rtekind == RTE_RELATION ||
+			   parent->rtekind == RTE_SUBQUERY);
+
 		/*
-		 * Get the userid from the relation's RTEPermissionInfo, though only
-		 * the tables mentioned in query are assigned RTEPermissionInfos.
-		 * Child relations (otherrels) simply use the parent's value.
+		 * For any RELATION rte, we need a userid with which to check
+		 * permission access. Baserels simply use their own RTEPermissionInfo's
+		 * checkAsUser.
+		 *
+		 * For otherrels normally there's no RTEPermissionInfo, so we use the
+		 * parent's, which normally has one. The exceptional case is that the
+		 * parent is a subquery, in which case the otherrel will have its own.
 		 */
-		if (parent == NULL)
+		if (rel->reloptkind == RELOPT_BASEREL ||
+			(rel->reloptkind == RELOPT_OTHER_MEMBER_REL &&
+			 parent->rtekind == RTE_SUBQUERY))
 		{
 			RTEPermissionInfo *perminfo;
 
-- 
2.35.3