Re: [ADMIN] shared_buffers and shmmax

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Alvaro Herrera <alvherre(at)commandprompt(dot)com>, valiouk(at)yahoo(dot)co(dot)uk, pgsql-docs(at)postgresql(dot)org, dx k9 <bitsandbytes88(at)hotmail(dot)com>
Subject: Re: [ADMIN] shared_buffers and shmmax
Date: 2008-12-17 14:11:20
Message-ID: 200812171411.mBHEBKX26736@momjian.us
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Tom Lane wrote:
> Bruce Momjian <bruce(at)momjian(dot)us> writes:
> > Tom Lane wrote:
> >> * If we do it like this then the left-hand column is really redundant,
> >> not to say wrong because the right-hand formulas depend on more than
> >> the single variable mentioned. How about something like
> >>
> >> Table 17-2 PostgreSQL shared memory usage
> >>
> >> Purpose Approximate number of bytes required (as of 8.3)
> >>
> >> Per-connection state (1800 + 270 * max_locks_per_transaction) * max_connections
> >> Autovacuum worker state (1800 + 270 * max_locks_per_transaction) * autovacuum_max_workers
> >> Prepared transaction state ...
> >> Shared disk buffers ...
> >> WAL buffers ...
> >> Fixed space requirements 770kB
>
> > OK, I updated it again:
>
> > http://momjian.us/tmp/pgsql/kernel-resources.html
>
> > I did change your left column wording because it could be interpreted as
> > something that changes during server execution, e.g. connections.
>
> [ shrug... ] I don't find what you did to be an improvement over what
> I suggested, but I don't have time to argue about it.

I decided I didn't like what I did either; updated version with new
headings and shorter descriptions:

http://momjian.us/tmp/pgsql/kernel-resources.html

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ If your life is a hard drive, Christ can be your backup. +

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