Postgresql - Tag - Tonderai Khataihttps://tldkhatai.com/tags/postgresql/Postgresql - Tag - Tonderai KhataiHugo -- gohugo.ioen-usTue, 06 Oct 2026 00:02:00 +0100Compare-and-Swap Updates in PostgreSQL, Explainedhttps://tldkhatai.com/posts/postgres-cas-explained/Tue, 06 Oct 2026 00:02:00 +0100Tonderai Khataihttps://tldkhatai.com/posts/postgres-cas-explained/

Compare-and-swap means: change this row, but only if it is still what I last saw. In SQL that’s an UPDATE with a guard in the WHERE clause, and you check how many rows it touched.

]]>PostgreSQL FOR UPDATE SKIP LOCKED, Explainedhttps://tldkhatai.com/posts/postgres-skip-locked-explained/Tue, 06 Oct 2026 00:01:00 +0100Tonderai Khataihttps://tldkhatai.com/posts/postgres-skip-locked-explained/

FOR UPDATE locks the rows a query returns. Add SKIP LOCKED and a row that another transaction has already locked is skipped instead of waited for.

]]>SKIP LOCKED vs CAS in PostgreSQLhttps://tldkhatai.com/posts/postgres-skip-locked-vs-cas/Tue, 06 Oct 2026 00:00:00 +0100Tonderai Khataihttps://tldkhatai.com/posts/postgres-skip-locked-vs-cas/

Eight workers poll the same jobs table. Each job must be processed by exactly one of them. Two PostgreSQL tools solve this, FOR UPDATE SKIP LOCKED and compare-and-swap (CAS), and on the same workload one claimed every job it tried for while the other lost most of its attempts.

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