Tuesday, August 17, 2010

Oracle Locks

1. Pessimistic Locking = select for update no wait
2. Optimistic Locking Using a Version Column,
3. Optimistic Locking Using a Checksum, CPU time

DEADLOCK is because foreign key is not indexed.

delete a parent will cause lock child table.

update or delete primary key will cause the same issue, when using ORM, the sql generated might do that.