| From: | Greg Smith <greg(at)2ndquadrant(dot)com> |
|---|---|
| To: | Ben Chobot <bench(at)silentmedia(dot)com> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: tuning bgwriter in 8.4.2 |
| Date: | 2010-02-23 01:47:36 |
| Message-ID: | 4B8333B8.2050502@2ndquadrant.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
Ben Chobot wrote:
> Is it reading it correctly to say that the bgwriter probably wouldn't
> help much, because a majority of the dirty pages appear to be popular?
Yes. The background writer cleaner process only does something useful
if there are pages with low usage counts it can evict. You would need
to increase shared_buffers significantly before it's likely that would
happen. Right now, 87% of your buffer cache has a usage count of 2 or
higher, which basically means it's filled with almost nothing but the
working set of data it never wants to evict unless it's for a checkpoint.
--
Greg Smith 2ndQuadrant US Baltimore, MD
PostgreSQL Training, Services and Support
greg(at)2ndQuadrant(dot)com www.2ndQuadrant.us
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