In High Performance Java Persistence book's 6.3.3.3 section it's written that Lost Update phenomena is possible in MySQL Repeatable Read isolation level. This is the screenshot:
Assuming the following(isolation level is REPEATABLE READ):
tx1 | tx2
-----------------------------------------------------------------------------------
START TRANSACTION; |
SELECT * FROM test WHERE id = 1; |
( say, DB_TRX_ID = 7 at this moment) |
|
| START TRANSACTION;
| SELECT * FROM test WHERE id = 1;
| UPDATE test SET name="x" WHERE id = 1;
| COMMIT;(say, makes DB_TRX_ID = 10)
|
UPDATE test SET name="y" WHERE id = 1;|
COMMIT;
Question:
Upon tx1 commit will MVCC detect that the row version(DB_TRX_ID) is not equal to 7 anymore(instead it's 10) and perform a rollback ? Or the commit will be succeeded causing a Lost Update ?