Simon Willison’s Weblog


Making PostgreSQL tick: New features in pg_cron (via) pg_cron adds cron-style scheduling directly to PostgreSQL. It’s a pretty mature extension at this point, and recently gained the ability to schedule repeating tasks at intervals as low as every 1s.

The examples in this post are really informative. I like this example, which cleans up the ever-growing cron.job_run_details table by using pg_cron itself to run the cleanup:

SELECT cron.schedule(’delete-job-run-details’, ’0 12 * * *’, $$DELETE FROM cron.job_run_details WHERE end_time < now()—interval ’3 days’$$);

pg_cron can be used to schedule functions written in PL/pgSQL, which is a great example of the kind of DSL that I used to avoid but I’m now much happier to work with because I know GPT-4 can write basic examples for me and help me understand exactly what unfamiliar code is doing.