best starting points....

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On a new system with 64G memory, what is the best starting points for
shmmax on OS and shared_buffers for Postgres. All databases combined
are about 50G.

I want to evaluate this with the two following scenarios:

1. this machine is running only Postgres, no other applications

2. this machine has postgres plus some other things (such as web server, etc).

What are the dangers for shmmax and shared_buffers to be confiugred very big for each of the two scenarios?

In case #1, if shmmax = 63G and shared_buffers = 50G, can it speed up Postgres (loading almost all dbs into memeory)?

Thanks,
Jessica



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Re: best starting points....

Em Sáb, 2008-07-12 às 05:03 -0700, Jessica Richard escreveu:
> On a new system with 64G memory, what is the best starting points for
> shmmax on OS and shared_buffers for Postgres. All databases combined
> are about 50G.
>=20
> I want to evaluate this with the two following scenarios:
>=20
> 1. this machine is running only Postgres, no other applications
>=20
> 2. this machine has postgres plus some other things (such as web
> server, etc).
>=20
> What are the dangers for shmmax and shared_buffers to be confiugred
> very big for each of the two scenarios?
>=20
> In case #1, if shmmax =3D 63G and shared_buffers =3D 50G, can it speed up
> Postgres (loading almost all dbs into memeory)?=20
=20
If to use virtually all memory to shared memory, you have concurrency
others process of the SO. Generally webserver is concurrency with
PostgreSQL in Shared Memory, if possible use in other server.


To initial point, recommends to use 25-40% to shared memory and
shared_buffers with value initial 25%.


Recommends visit:


- http://wiki.postgresql.org/wiki/Performance_Optimization



Best Regards,
--=20
Fernando Ike de Oliveira

--=20
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