https://www.postgresscripts.com/tags/row-locking/Recent content in Row Locking on Postgres ScriptsHugo -- gohugo.ioenPostgresScripts.comSat, 24 Oct 2026 00:00:00 +0000https://www.postgresscripts.com/post/claim-queue-rows-with-for-update-skip-locked-in-postgresql/Sat, 24 Oct 2026 00:00:00 +0000https://www.postgresscripts.com/post/claim-queue-rows-with-for-update-skip-locked-in-postgresql/ <h2 id="claim-queue-rows-with-for-update-skip-locked-in-postgresql">Claim Queue Rows with FOR UPDATE SKIP LOCKED in PostgreSQL</h2> <p>Several workers poll the same job table with <code>SELECT ... LIMIT 10</code>, and a plain LIMIT does nothing to stop two of them from <a href="https://www.crunchydata.com/blog/message-queuing-using-native-postgresql">getting the same list of items to process</a>. Add <code>FOR UPDATE</code> and <a href="https://www.crunchydata.com/blog/message-queuing-using-native-postgresql">the second worker hangs</a> until the first one commits. Put <code>FOR UPDATE SKIP LOCKED</code> in the CTE of a batch <code>DELETE ... RETURNING</code> and <a href="https://www.postgresql.org/docs/current/sql-select.html">rows that cannot be locked immediately are skipped</a>, so each worker deletes and receives its own batch in one statement.</p>