################################################################################ # # UPDATE using multiple statements. Subtract a value (4) from one field, then # add the same value to another field in the same row. # # Mind any tx errors, ROLLBACK if needed to "equalize" different engines. # ################################################################################ SET autocommit = 0; START TRANSACTION; eval SET @conn_id = CONNECTION_ID(), @thread_id = 0; --error 0, ER_LOCK_DEADLOCK, ER_LOCK_WAIT_TIMEOUT, ER_CHECKREAD UPDATE t1 SET `int1` = `int1` - 4, `id` = 4, `is_consistent` = 0, `connection_id` = @conn_id, `thread_id` = @thread_id WHERE `pk` = 4; --source suite/engines/rr_trx/include/check_for_error_rollback.inc --echo *** UPDATEing row with pk = 4 and `int1_key` +=4 if above statement succeeded (query log disabled)... if (!$error) { # This is conditional, so disable query log to avoid irrelevant diffs. --disable_query_log --error 0, ER_LOCK_DEADLOCK, ER_LOCK_WAIT_TIMEOUT, ER_CHECKREAD UPDATE t1 SET `int1_key` = `int1_key` + 4, `is_consistent` = 1, `connection_id` = @conn_id, `thread_id` = @thread_id WHERE `pk` = 4; --source suite/engines/rr_trx/include/check_for_error_rollback.inc --enable_query_log } COMMIT;