SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;
connect  con1, localhost, root,,;
SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;
connection default;
CREATE TABLE t1(c1 VARCHAR(10) NOT NULL, c2 VARCHAR(10) NOT NULL, c3 VARCHAR(10) NOT NULL);
INSERT INTO t1(c1, c2, c3) VALUES('A1','B1','IT1'), ('A2','B2','IT1'), ('A3','B3','IT1'), ('A4','B4','IT1'), ('A5','B5','IT1'), ('A6','B6','IT1'), ('A7','B7','IT1');
CREATE TABLE t2(c1 VARCHAR(10) NOT NULL, c2 VARCHAR(10) NOT NULL, c3 VARCHAR(10) NOT NULL);
INSERT INTO t2(c1, c2, c3) VALUES ('A3','B3','IT2'), ('A2','B2','IT2'), ('A4','B4','IT2'), ('A5','B5','II2');
CREATE TABLE result(id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT, c1 VARCHAR(10) NOT NULL, c2 VARCHAR(10),
c3 VARCHAR(10), update_count INT DEFAULT 0, UNIQUE KEY uniq_idx (c1,c2), PRIMARY KEY (id)) ENGINE = innodb;
SET DEBUG_SYNC = "ha_write_row_end WAIT_FOR flushed EXECUTE 1";
INSERT INTO result(c1, c2, c3) SELECT * FROM t1 ON DUPLICATE KEY UPDATE c2=t1.c2, c3='UT1', update_count=update_count+1;
connection con1;
INSERT INTO result(c1, c2, c3) SELECT * FROM t2 ON DUPLICATE KEY UPDATE c2=t2.c2, c3='UT2', update_count=update_count+1;
SET DEBUG_SYNC = "now SIGNAL flushed";
connection default;
SELECT * FROM result;
id	c1	c2	c3	update_count
1	A1	B1	IT1	0
2	A3	B3	UT1	1
3	A2	B2	UT1	1
4	A4	B4	UT1	1
5	A5	B5	UT1	1
9	A6	B6	IT1	0
10	A7	B7	IT1	0
DROP TABLE t1;
DROP TABLE t2;
DROP TABLE result;
SET DEBUG_SYNC = "RESET";
