SET autocommit = 0;
START TRANSACTION;
SET @conn_id = CONNECTION_ID(), @thread_id = 0;
UPDATE t1 SET `int1` = `int1` - 4, 
`id` = 4,
`is_consistent` = 0,
`connection_id` = @conn_id,
`thread_id` = @thread_id
WHERE `pk` = 4;
*** UPDATEing row with pk = 4 and `int1_key` +=4 if above statement succeeded (query log disabled)...
COMMIT;