Re: tuning our database by increasing shared buffer

Hello All

I am working with Barbara on this project and I am curios about what
would be a good starting place for setting the max_fsm_relations and
max_fsm_pages. Here are the current values max_fsm_pages = 153600 and
the max_fsm_relations is set to the default of 1000. I have have read
that the output from vacuum can help determine the values. We are using
the autovacuum daemon. Is there some logging from that process that
could help.

Thanks

John Allgood

Senior Systems Administrator

Turbo, division of OHL

2251 Jesse Jewell Pky. NE

Gainesville, GA 30507

tel: (678) 989-3051 fax: (770) 531-7878

jallgood(at)ohl(dot)com <mailto:jallgood(at)ohl(dot)com>

www.ohl.com <http://www.ohl.com>

From: pgsql-admin-owner(at)postgresql(dot)org
[mailto:pgsql-admin-owner(at)postgresql(dot)org] On Behalf Of Barbara
Stephenson
Sent: Tuesday, June 23, 2009 3:43 PM
To: Tom Lane
Cc: pgsql-admin(at)postgresql(dot)org
Subject: Re: [ADMIN] tuning our database by increasing shared buffer

Thank ypu!

Tom Lane wrote:

Barbara Stephenson <barbara(at)turbocorp(dot)com>
<mailto:barbara(at)turbocorp(dot)com> writes:

We will be consolidating from 4 databases to 2 and want to make
sure that
these parameters are the only ones that need changing. Please
advise.

Current
Future
=====
=====
Max_connection = 50 125
Shared_buffers = 16MB 48MB

You will need to make sure that the FSM size parameters are correct for
the combined databases, too.

Shouldn't we increase the max_locks_per_transaction from 64 to
100 or 128
since we have more than doubled the # of connections?

No, because the lock table size automatically scales with
max_connections. (Probably max_locks_per_transaction should have been
called max_locks_per_connection ...)

max_prepared_transaction is set at default of 5 which is says if
we use it to
set it to max_connection.

Are you using prepared transactions at all? If not, I'd actually
recommend setting that to zero to make sure nobody creates a prepared
transaction accidentally. You do *not* want anyone doing PREPARE
TRANSACTION unless there's an XA manager or something in place to make
sure the prepared xact gets committed or rolled back reasonably soon.

regards, tom lane

--

Regards,

Barbara Stephenson
EDI Specialist/Programmer
Turbo, division of OHL
2251 Jesse Jewell Pkwy
Gainesville, GA 30507
tel: (678)989-3020 fax: (404)935-6171
barbara(at)turbocorp(dot)com
www.ohl.com

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