On Thursday 30 October 2008, "Oliver Johnson" <oliverjjohnson@gmail.com>
wrote:
> Another thing to note, we have VACUUM ANALYZE running on an hourly
> interval and the switch from CPU to IO wait appears to always coincide
> with a vacuum.
>
> What might cause this shift?
The extra disk access caused by vacuum? That seems pretty obvious.
Use auto-vacuum. There's no reason to vacuum your entire database every hour
(doing so reads from disk the entirety of every table and index, and
generates some write activity).
--
Alan