From 45007620d716acf0831cd780c807eee3e8e59a25 Mon Sep 17 00:00:00 2001
From: Taiki Koshino <koshino@sraoss.co.jp>
Date: Sat, 19 Sep 2026 03:22:25 +0900
Subject: [PATCH v2] Preserve dml_adaptive state on ROLLBACK TO SAVEPOINT.

dml_adaptive() used is_commit_or_rollback_query() to detect the end of
a transaction. However, this function also returns true for ROLLBACK TO
SAVEPOINT, which does not end the transaction.

Consequently, ROLLBACK TO SAVEPOINT cleared is_in_transaction and the
transaction write list. Subsequent SELECTs on previously modified tables
could then be load balanced to a standby and return stale data.

Exclude ROLLBACK TO SAVEPOINT from the transaction-end branch and keep
the accumulated write list until COMMIT or ROLLBACK.

Author: zourenli
Reviewed-by: Taiki Koshino <koshino@sraoss.co.jp>
Discussion: https://github.com/pgpool/pgpool2/issues/173
Backpatch-through: v4.3
---
 src/context/pool_query_context.c              |  7 +++-
 .../032.dml_adaptive_load_balance/test.sh     | 41 +++++++++++++++++++
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/src/context/pool_query_context.c b/src/context/pool_query_context.c
index 16ac34825..b9bfe3229 100644
--- a/src/context/pool_query_context.c
+++ b/src/context/pool_query_context.c
@@ -2003,7 +2003,12 @@ dml_adaptive(Node *node, char *query)
 				session_context->transaction_temp_write_oid_list = NIL;
 				session_context->transaction_temp_write_dboid = 0;
 			}
-			else if (is_commit_or_rollback_query(node))
+			/*
+			 * Only COMMIT and normal ROLLBACK query.
+			 * ROLLBACK TO SAVEPOINT must preserve the transaction state
+			 * and accumulated write list.
+			 */
+			else if (is_commit_query(node) || is_rollback_query(node))
 			{
 				session_context->is_in_transaction = false;
 
diff --git a/src/test/regression/tests/032.dml_adaptive_load_balance/test.sh b/src/test/regression/tests/032.dml_adaptive_load_balance/test.sh
index 5692249fc..98885dc5d 100755
--- a/src/test/regression/tests/032.dml_adaptive_load_balance/test.sh
+++ b/src/test/regression/tests/032.dml_adaptive_load_balance/test.sh
@@ -37,6 +37,7 @@ CREATE TABLE t1(i INTEGER);
 CREATE TABLE t2(i INTEGER);
 CREATE TABLE t3(i INTEGER);
 CREATE TABLE tF(i INTEGER);
+CREATE TABLE t_savepoint(i INTEGER);
 CREATE FUNCTION f1(INTEGER) returns INTEGER AS 'SELECT \$1' LANGUAGE SQL;
 EOF
 # wait for the newly created tables replicated
@@ -142,6 +143,46 @@ EOF
 	fi
 	echo ok: T2 final read was load balanced.
 
+
+# check if ROLLBACK TO SAVEPOINT preserves the transaction write list
+$PSQL -X -At -v ON_ERROR_STOP=1 test > result.txt <<EOF
+BEGIN;
+INSERT INTO t_savepoint VALUES(1);
+SAVEPOINT sp;
+INSERT INTO t_savepoint VALUES(2);
+ROLLBACK TO SAVEPOINT sp;
+SELECT sum(i), 'QUERY ID T3-1' FROM t_savepoint;	-- NO LOAD balance
+ROLLBACK;
+EOF
+
+	if [ $? != 0 ];then
+		echo fail: ROLLBACK TO SAVEPOINT test query failed.
+		./shutdownall
+		exit 1
+	fi
+
+	grep -Fx '1|QUERY ID T3-1' result.txt >/dev/null 2>&1
+	if [ $? != 0 ];then
+		echo fail: update before SAVEPOINT was not visible.
+		./shutdownall
+		exit 1
+	fi
+
+	grep -F "SELECT sum(i), 'QUERY ID T3-1' FROM t_savepoint;" log/pgpool.log |grep "DB node id: 0">/dev/null 2>&1
+	if [ $? != 0 ];then
+		echo fail: read after ROLLBACK TO SAVEPOINT was not sent to primary.
+		./shutdownall
+		exit 1
+	fi
+
+	grep -F "SELECT sum(i), 'QUERY ID T3-1' FROM t_savepoint;" log/pgpool.log |grep "DB node id: 1">/dev/null 2>&1
+	if [ $? = 0 ];then
+		echo fail: read after ROLLBACK TO SAVEPOINT was wrongly load balanced.
+		./shutdownall
+		exit 1
+	fi
+	echo ok: ROLLBACK TO SAVEPOINT preserved the transaction write list.
+
         ./shutdownall
         cd ..
 done
-- 
2.52.0