Concurrent INSERT in the Same table

Transaction T1:

START TRANSACTION;
INSERT INTO test VALUES(2,'test2','test123');
COMMIT;

Transaction T2:

START TRANSACTION;
INSERT INTO test VALUES(3,'test3','test123');
COMMIT;

Scenario 1:

T1 is started but not committed. At this time, T2 is started. After INSERT of T1 is complete, INSERT of T2 is executed and succeeds. At the READ COMMITTED and REPEATABLE READ levels, the SELECT statement of T1 cannot see data inserted by T2, and a query in T2 cannot see data inserted by T1.

Scenario 2:

• READ COMMITTED level

  T1 is started but not committed. At this time, T2 is started. After INSERT of T1 is complete, T1 is committed. In T2, a query executed after INSERT can see the data inserted by T1.

• REPEATABLE READ level

  T1 is started but not committed. At this time, T2 is started. After INSERT of T1 is complete, T1 is committed. In T2, a query executed after INSERT cannot see the data inserted by T1.