connection node_2; connection node_1; CREATE TABLE t1 (id INT PRIMARY KEY) ENGINE=InnoDB; INSERT INTO t1 VALUES (1); connection node_2; ALTER TABLE t1 ADD COLUMN f2 INTEGER, LOCK=SHARED; connection node_1; INSERT INTO t1 VALUES (2, 2); SELECT COUNT(*) AS EXPECT_2 FROM t1; EXPECT_2 2 SELECT * FROM t1; id f2 1 NULL 2 2 connection node_2; INSERT INTO t1 VALUES (3, 3); SELECT COUNT(*) AS EXPECT_3 FROM t1; EXPECT_3 3 SELECT * FROM t1; id f2 1 NULL 2 2 3 3 DROP TABLE t1;