[postgis-users] postgis tuning parameters

[Webb Sprague]

> > When performing complex queries, with thousands of records and
> > geometries I am noticing that the postmaster process never exceeds 1%
> > of my system's memory (2Gb). I have tried setting the shared_buffers
> > parameter to values > 2000 ... but this only leads to an error when the
> > postgres server is restarted: cannot allocate this much mem, check the
> > SHMMAX kernel parameter.

It sounds to me like you need to recompile Postgres with new values
for SHMAX (and maybe other parameters too - I would ask on the
Postgres General list).  Building postgres is trivial, and if it is
for a production machine it might be quite worthwhile -- there might
be options for stripping debug symbols etc .

-W

> >
> > Perhaps some answers on are this page:
> > http://www.redhat.com/docs/manuals/database/RHDB-2.1-Manual/admin_user/
> > kernel-resources.html
> >
> > or in the minds of people on the list. The machine in question is
> > mostly used for such queries and I would like postgis to be able to
> > better utilize the resources available.
> >
> > Cheers,
> >
> > Dylan
>
>
> Hi Dylan,
>
> Indeed, everything you need to know should be on that page - here is the
> most recent version:
> http://www.postgresql.org/docs/8.2/interactive/kernel-resources.html.
> Experiment with different settings, but most people tend to recommend
> about 25% of your available RAM (~60,000 buffers for 2Gb) for a
> dedicated database server.
>
>
> HTH,
>
> Mark.
>
> --
> ILande - Open Source Consultancy
> http://www.ilande.co.uk
>
>
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