Monitoring and tuning vacuum

If you're currently waiting for a long running vacuum (or autovacuum) to finish, go straight to the How to do it... section.

If you've just had a long running vacuum then you may want to think about setting a few parameters.

Getting ready

autovacuum_max_workers should always be set to more than 2. Setting it too high may not be very useful, so be careful.

Setting vacuum_cost_delay too high is counterproductive. VACUUM is your friend, not your enemy, so delaying it until it doesn't happen at all just makes things worse.

maintenance_work_mem should be set to anything up to 1 GB, according to how much memory you can allocate to this task at this time.

Let's watch what happens when...