Re: SAN performance mystery

On Jun 16, 2006, at 5:11 AM, Tim Allen wrote:
>
> One curious thing is that some postgres backends seem to spend an
> inordinate amount of time in uninterruptible iowait state. I found
> a posting to this list from December 2004 from someone who reported
> that very same thing. For example, bringing down postgres on the
> customer box requires kill -9, because there are invariably one or
> two processes so deeply uninterruptible as to not respond to a
> politer signal. That indicates something not quite right, doesn't it?
>

Sounds like there could be a driver/array/kernel bug there that is
kicking the performance down the tube.
If it was PG's fault it wouldn't be stuck uninterruptable.

--
Jeff Trout <jeff@jefftrout.com>
http://www.dellsmartexitin.com/
http://www.stuarthamm.net/