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Oracle Database Contentions 2

Row Lock Contentions

Angudi Tech

4/27/20261 min read

Row Lock Contentions

Databases must be modelled keeping application design in mind. There are various APIs using same system to verify or fetch regulatory data. In such scenario contentions are bound to happen. when several simultaneous sessions try to update or delete the same row, or insert duplicate values into unique or primary key constraints, necessitating that one transaction waits until the blocking session either commits or rolls back. This is referred as an enq: TX - row lock contention wait event. To temporary resolve this issue, it is necessary to identify the blocker and kill the session, so rest sessions on the same blocks are released.

To resolve the persistent issues permanently, examine the application structure and rectify the logic if necessary. This application logic should be tested across various databases to analyse its outcomes.

Row lock contentions arise when a single row in the database is accessed by multiple sessions. If the operation is solely a SELECT statement, it does not lead to contention. However, a "select for update" statement can result in contention. INSERT, DELETE, and UPDATE statements necessitate the application of a lock on the rows. Exclusive and shared locks generate a queue, allowing only one session to access the resource at any given time.

At Angudi Tech, we address the issues causing contentions, conduct root cause analysis, and deliver compliant solutions through both manual and automated methods.