Re: Moving postgresql.conf tunables into 2003... - Mailing list pgsql-performance

From Tom Lane
Subject Re: Moving postgresql.conf tunables into 2003...
Date
Msg-id 2422.1057264735@sss.pgh.pa.us
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In response to Moving postgresql.conf tunables into 2003...  (Sean Chittenden <sean@chittenden.org>)
Responses Re: Moving postgresql.conf tunables into 2003...  (Sean Chittenden <sean@chittenden.org>)
List pgsql-performance
Sean Chittenden <sean@chittenden.org> writes:
> What are the odds of going through and revamping some of the tunables
> in postgresql.conf for the 7.4 release?

I was arguing awhile back for bumping the default shared_buffers up,
but the discussion trailed off with no real resolution.

> I was just working with
> someone on IRC and on their 7800 RPM IDE drives, their
> random_page_cost was ideally suited to be 0.32: a far cry from 4.

It is not physically sensible for random_page_cost to be less than one.
The system only lets you set it there for experimental purposes; there
is no way that postgresql.conf.sample will recommend it.  If you needed
to push it below one to force indexscans, there is some other problem
that needs to be solved.  (I'd wonder about index correlation myself;
we know that that equation is pretty bogus.)

> I know Josh is working on revamping the postgresql.conf file, but
> would it be possible to include suggested values for various bits of
> hardware and then solicit contributions from admins on this list who
> have tuned their DB correctly?

I think such material belongs in the SGML docs, not hidden away in a
config file that people may not look at...

            regards, tom lane

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