This indicates contention for row-level lock. This wait occurs when a transaction tries to update or delete rows that are currently locked by another transaction. This usually is an application issue. The waiting session will wait until the blocking session commits or rolls back its transaction.

How do I fix row lock contention?

To solve this particular instance, the session holding the lock must perform a COMMIT or ROLLBACK. In mode 4, a TX wait can occur if there is a potential duplicate in a unique index. When two sessions try to insert the same key value the second session must wait to see if an ORA-001 should be raised.

What is row lock wait?

When you issue a commit or rollback on the first session, and the second statement errors or completes (depending on whether you commit or rollback the first session) it will increase the value for row lock waits in v$segstat (and v$segment_statistics) for the index by 1. ...