| From: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
|---|---|
| To: | Bruce Momjian <bruce(at)momjian(dot)us> |
| Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Figuring out shared buffer pressure |
| Date: | 2012-05-30 17:38:10 |
| Message-ID: | CAMkU=1zysj38SRuDKtSngUuHZEUqfvFriYAKN+RNrRpHPSZeBw@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Wed, May 30, 2012 at 9:56 AM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> As part of a blog, I started looking at how a user could measure the
> pressure on shared buffers, e.g. how much are they being used, recycled,
> etc.
>
> They way you normally do it on older operating systems is to see how
> many buffers on the free list (about to be reused) are reclaimed as
> needed --- that usually indicates kernel cache pressure. Unfortunately,
> we don't have a freelist, except for initial assignment of shared
> buffers on startup.
Isn't that what the buffers_alloc from pg_stat_bgwriter is ?
Cheers,
Jeff
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