Bug#30194841 INSERT ON DUPLICATE KEY UPDATE UPDATES THE WRONG ROW

test case only

mysql-test/r/insert_debug.result

+SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;
+SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;
+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;
+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";
+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";

mysql-test/t/insert_debug-master.opt

+--innodb_autoinc_lock_mode=2

mysql-test/t/insert_debug.test

+source include/have_innodb.inc;
+source include/have_debug.inc;
+source include/have_debug_sync.inc;
+
+SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;
+
+connect (con1, localhost, root,,);
+SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;
+
+connection default;
+
+let $conn0_id= `SELECT CONNECTION_ID()`;
+
+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;
+
+# Insert one row from 't1' into the 'result' table and wait on a debug sync
+# point. The next insert statement from an session 2 inserts values that would
+# lead to unique key clash, when this insert resumes.
+# The subsequent inserts of this statement(after resume) will fail because of a
+# clash with the unique index, and are expected to update the row which clashes
+# with the unique key.
+# Without the fix for bug#30194841 a stale auto increment value, would cause a
+# collision with existing auto increment column value and ends up updating that
+# colliding row, instead of the row colliding with the unique index.
+SET DEBUG_SYNC = "ha_write_row_end WAIT_FOR flushed EXECUTE 1";
+send INSERT INTO result(c1, c2, c3) SELECT * FROM t1 ON DUPLICATE KEY UPDATE c2=t1.c2, c3='UT1', update_count=update_count+1;
+
+# While session 1 is waiting (after one insert), insert rows that will cause a clash
+# with the inserts of session 1 on the unique key.
+connection con1;
+
+# Wait for the session 1 to hit the debug sync point.
+let $wait_condition=SELECT 1 FROM information_schema.processlist WHERE id = $conn0_id AND state LIKE '%ha_write_row_end%';
+--source include/wait_condition.inc
+
+INSERT INTO result(c1, c2, c3) SELECT * FROM t2 ON DUPLICATE KEY UPDATE c2=t2.c2, c3='UT2', update_count=update_count+1;
+
+# Signal to resume the insert statement in session 1
+SET DEBUG_SYNC = "now SIGNAL flushed";
+connection default;
+reap;
+SELECT * FROM result;
+
+DROP TABLE t1;
+DROP TABLE t2;
+DROP TABLE result;
+SET DEBUG_SYNC = "RESET";