ORACLE – enq: TX row lock contention
Enqueues are locks that coordinate access to database resources. enq: wait eventindicates that the session is waiting for a lock that is held by another session. The amount of wait time associated with this wait event is excessive and can be responsible for performance issues observed in the application. TX enqueue are acquired exclusive when a transaction initiates its first change and held until the transaction does a COMMIT or ROLLBACK. Some situations of TX enqueue: – Waits for TX in mode 6 occurs when a session is waiting for a row level lock that is already held by another...