diff --git a/src/backend/utils/mmgr/portalmem.c b/src/backend/utils/mmgr/portalmem.c
index 04ea32f49f..d34cab0eb8 100644
--- a/src/backend/utils/mmgr/portalmem.c
+++ b/src/backend/utils/mmgr/portalmem.c
@@ -689,13 +689,23 @@ PreCommit_Portals(bool isPrepare)
 
 		/*
 		 * Do not touch active portals --- this can only happen in the case of
-		 * a multi-transaction utility command, such as VACUUM.
+		 * a multi-transaction utility command, such as VACUUM, or a commit in
+		 * a procedure.
 		 *
 		 * Note however that any resource owner attached to such a portal is
-		 * still going to go away, so don't leave a dangling pointer.
+		 * still going to go away, so don't leave a dangling pointer.  Also
+		 * unregister any snapshots held by the portal, mainly to avoid
+		 * snapshot leak warnings from ResourceOwnerRelease().
 		 */
 		if (portal->status == PORTAL_ACTIVE)
 		{
+			if (portal->holdSnapshot)
+			{
+				if (portal->resowner)
+					UnregisterSnapshotFromOwner(portal->holdSnapshot,
+												portal->resowner);
+				portal->holdSnapshot = NULL;
+			}
 			portal->resowner = NULL;
 			continue;
 		}
diff --git a/src/pl/plpgsql/src/expected/plpgsql_transaction.out b/src/pl/plpgsql/src/expected/plpgsql_transaction.out
index 0b5a039b89..77a83adab5 100644
--- a/src/pl/plpgsql/src/expected/plpgsql_transaction.out
+++ b/src/pl/plpgsql/src/expected/plpgsql_transaction.out
@@ -463,6 +463,36 @@ SELECT * FROM test2;
  42
 (1 row)
 
+-- Test transaction in procedure with output parameters.  This uses a
+-- different portal strategy and different code paths in pquery.c.
+CREATE PROCEDURE transaction_test10a(INOUT x int)
+LANGUAGE plpgsql
+AS $$
+BEGIN
+  x := x + 1;
+  COMMIT;
+END;
+$$;
+CALL transaction_test10a(10);
+ x  
+----
+ 11
+(1 row)
+
+CREATE PROCEDURE transaction_test10b(INOUT x int)
+LANGUAGE plpgsql
+AS $$
+BEGIN
+  x := x - 1;
+  ROLLBACK;
+END;
+$$;
+CALL transaction_test10b(10);
+ x 
+---
+ 9
+(1 row)
+
 DROP TABLE test1;
 DROP TABLE test2;
 DROP TABLE test3;
diff --git a/src/pl/plpgsql/src/sql/plpgsql_transaction.sql b/src/pl/plpgsql/src/sql/plpgsql_transaction.sql
index 236db9bf2b..0ed9ab873a 100644
--- a/src/pl/plpgsql/src/sql/plpgsql_transaction.sql
+++ b/src/pl/plpgsql/src/sql/plpgsql_transaction.sql
@@ -387,6 +387,31 @@ $$;
 SELECT * FROM test2;
 
 
+-- Test transaction in procedure with output parameters.  This uses a
+-- different portal strategy and different code paths in pquery.c.
+CREATE PROCEDURE transaction_test10a(INOUT x int)
+LANGUAGE plpgsql
+AS $$
+BEGIN
+  x := x + 1;
+  COMMIT;
+END;
+$$;
+
+CALL transaction_test10a(10);
+
+CREATE PROCEDURE transaction_test10b(INOUT x int)
+LANGUAGE plpgsql
+AS $$
+BEGIN
+  x := x - 1;
+  ROLLBACK;
+END;
+$$;
+
+CALL transaction_test10b(10);
+
+
 DROP TABLE test1;
 DROP TABLE test2;
 DROP TABLE test3;