[TOC] > [github](https://github.com/citusdata/pg_cron) ## 概述 语法 ``` ┌───────────── min (0 - 59) │ ┌────────────── hour (0 - 23) │ │ ┌─────────────── day of month (1 - 31) or last day of the month ($) │ │ │ ┌──────────────── month (1 - 12) │ │ │ │ ┌───────────────── day of week (0 - 6) (0 to 6 are Sunday to │ │ │ │ │ Saturday, or use names; 7 is also Sunday) │ │ │ │ │ │ │ │ │ │ * * * * * ``` ## 示例 ``` -- Delete old data on Saturday at 3:30am (GMT) SELECT cron.schedule('30 3 * * 6', $$DELETE FROM events WHERE event_time < now() - interval '1 week'$$); schedule ---------- 42 -- Vacuum every day at 10:00am (GMT) SELECT cron.schedule('nightly-vacuum', '0 10 * * *', 'VACUUM'); schedule ---------- 43 -- Change to vacuum at 3:00am (GMT) SELECT cron.schedule('nightly-vacuum', '0 3 * * *', 'VACUUM'); schedule ---------- 43 -- Stop scheduling jobs SELECT cron.unschedule('nightly-vacuum' ); unschedule ------------ t SELECT cron.unschedule(42); unschedule ------------ t -- Vacuum every Sunday at 4:00am (GMT) in a database other than the one pg_cron is installed in SELECT cron.schedule_in_database('weekly-vacuum', '0 4 * * 0', 'VACUUM', 'some_other_database'); schedule ---------- 44 -- Call a stored procedure every 5 seconds SELECT cron.schedule('process-updates', '5 seconds', 'CALL process_updates()'); -- Process payroll at 12:00 of the last day of each month SELECT cron.schedule('process-payroll', '0 12 $ * *', 'CALL process_payroll()'); ```