From 38a7ace1082e8a668007b800f6df379c38a37747 Mon Sep 17 00:00:00 2001
From: Ubuntu <ubuntu@localhost.localdomain>
Date: Fri, 31 Jul 2026 10:26:54 +0800
Subject: [PATCH] Only test for sublink pullup

---
 src/backend/optimizer/plan/subselect.c |  2 +-
 src/backend/optimizer/util/var.c       | 49 ++++++++++++++++++++++++++
 src/include/optimizer/optimizer.h      |  1 +
 3 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
index 6aa8971c95d..03a37421bce 100644
--- a/src/backend/optimizer/plan/subselect.c
+++ b/src/backend/optimizer/plan/subselect.c
@@ -1650,7 +1650,7 @@ convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink,
 	 * On the other hand, the WHERE clause must contain some Vars of the
 	 * parent query, else it's not gonna be a join.
 	 */
-	if (!contain_vars_of_level(whereClause, 1))
+	if (!contain_vars_of_level_parent(whereClause, 1))
 		return NULL;
 
 	/*
diff --git a/src/backend/optimizer/util/var.c b/src/backend/optimizer/util/var.c
index 907a255c36f..7a20c6ca021 100644
--- a/src/backend/optimizer/util/var.c
+++ b/src/backend/optimizer/util/var.c
@@ -76,6 +76,7 @@ static bool pull_varattnos_walker(Node *node, pull_varattnos_context *context);
 static bool pull_vars_walker(Node *node, pull_vars_context *context);
 static bool contain_var_clause_walker(Node *node, void *context);
 static bool contain_vars_of_level_walker(Node *node, int *sublevels_up);
+static bool contain_vars_of_level_walker2(Node *node, int *sublevels_up);
 static bool contain_vars_returning_old_or_new_walker(Node *node, void *context);
 static bool locate_var_of_level_walker(Node *node,
 									   locate_var_of_level_context *context);
@@ -492,7 +493,55 @@ contain_vars_of_level_walker(Node *node, int *sublevels_up)
 								  sublevels_up);
 }
 
+bool
+contain_vars_of_level_parent(Node *node, int levelsup)
+{
+	int			sublevels_up = levelsup;
 
+	return query_or_expression_tree_walker(node,
+										   contain_vars_of_level_walker2,
+										   &sublevels_up,
+										   0);
+}
+
+static bool
+contain_vars_of_level_walker2(Node *node, int *sublevels_up)
+{
+	if (node == NULL)
+		return false;
+	if (IsA(node, Var))
+	{
+		if (((Var *) node)->varlevelsup == *sublevels_up)
+			return true;		/* abort tree traversal and return true */
+		return false;
+	}
+	if (IsA(node, CurrentOfExpr))
+	{
+		if (*sublevels_up == 0)
+			return true;
+		return false;
+	}
+	if (IsA(node, PlaceHolderVar))
+	{
+		if (((PlaceHolderVar *) node)->phlevelsup == *sublevels_up)
+			return true;		/* abort the tree traversal and return true */
+		/* else fall through to check the contained expr */
+	}
+	if (IsA(node, Query))
+	{
+		/* Recurse into subselects */
+		bool		result;
+
+		result = query_tree_walker((Query *) node,
+								   contain_vars_of_level_walker2,
+								   sublevels_up,
+								   0);
+		return result;
+	}
+	return expression_tree_walker(node,
+								  contain_vars_of_level_walker2,
+								  sublevels_up);
+}
 /*
  * contain_vars_returning_old_or_new
  *	  Recursively scan a clause to discover whether it contains any Var nodes
diff --git a/src/include/optimizer/optimizer.h b/src/include/optimizer/optimizer.h
index cb6241e2bdd..cd17ffc92bf 100644
--- a/src/include/optimizer/optimizer.h
+++ b/src/include/optimizer/optimizer.h
@@ -209,6 +209,7 @@ extern void pull_varattnos(Node *node, Index varno, Bitmapset **varattnos);
 extern List *pull_vars_of_level(Node *node, int levelsup);
 extern bool contain_var_clause(Node *node);
 extern bool contain_vars_of_level(Node *node, int levelsup);
+extern bool contain_vars_of_level_parent(Node *node, int levelsup);
 extern bool contain_vars_returning_old_or_new(Node *node);
 extern int	locate_var_of_level(Node *node, int levelsup);
 extern List *pull_var_clause(Node *node, int flags);
-- 
2.43.0