Coordinate concurrent updates

Use transactions and validate concurrency behavior before coordinating workers.

Example

CREATE TABLE docs_locks (id BIGINT PRIMARY KEY, status TEXT);
INSERT INTO docs_locks VALUES (1, 'pending');

BEGIN;
SELECT id, status FROM docs_locks WHERE id = 1 FOR UPDATE;
UPDATE docs_locks SET status = 'running' WHERE id = 1;
COMMIT;

Behavior

A successful FOR UPDATE statement alone does not establish a complete queue-claim guarantee. Test behavior with two concurrent connections in your release. Handle transaction conflicts, timeouts and deadlocks through bounded retries. Do not assume SKIP LOCKED, advisory locks or LOCK TABLE match another database without a specific compatibility check.

Related

SQL reference · Application guide · Troubleshooting