Re: Sun Fire T2000 and PostgreSQL 8.1.3 - Mailing list pgsql-performance

From Juan Casero \(FL FLC\)
Subject Re: Sun Fire T2000 and PostgreSQL 8.1.3
Date
Msg-id 7583B3F1891CC0429FA4A44952AA539C66FA7E@wfm-exchprd2.wfm.pvt
Whole thread Raw
In response to Sun Fire T2000 and PostgreSQL 8.1.3  ("Juan Casero \(FL FLC\)" <Juan.Casero@wholefoods.com>)
Responses Re: Sun Fire T2000 and PostgreSQL 8.1.3  (Josh Berkus <josh@agliodbs.com>)
Re: Sun Fire T2000 and PostgreSQL 8.1.3  (Markus Schaber <schabi@logix-tt.com>)
List pgsql-performance
Ok that is beginning to become clear to me.  Now I need to determine if
this server is worth the investment for us.  Maybe it is not a speed
daemon but to be honest the licensing costs of an SMP aware RDBMS is
outside our budget.  When postgresql starts does it start up a super
server process and then forks copies of itself to handle incoming
requests?  Or do I have to specify how many server processes should be
started up?   I figured maybe I can take advantage of the multiple cpu's
on this system by starting up enough postgres server processes to handle
large numbers of incoming connections.  I have this server available for
sixty days so I may as well explore the performance of postgresql on it.



Thanks,
Juan

-----Original Message-----
From: pgsql-performance-owner@postgresql.org
[mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Luke
Lonergan
Sent: Wednesday, April 05, 2006 5:37 PM
To: Juan Casero (FL FLC); pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Sun Fire T2000 and PostgreSQL 8.1.3

Juan,

On 4/5/06 1:54 PM, "Juan Casero (FL FLC)" <Juan.Casero@wholefoods.com>
wrote:

> I am not sure about this.  I mean I have postgresql 8.1.3 running on
> my Windows XP P4 HT laptop that I use for testing my webapps.  When I
> hit this pgsql on this laptop with a large query I can see the load
> spike up really high on both of my virtual processors.  Whatever,
> pgsql is doing it looks like both cpu's are being used indepently. The

> usage curve is not identical on both of them that makes me think that
> parts of the server are multithreaded.  Admittedly I am not familiar
> with the source code fo postgresql so I was hoping maybe one of the
> developers who is could definitely answer this question.

There's no part of the Postgres backend that is threaded or
multi-processed.
A reasonable explanation for your windows experience is that your web
server or the psql client may be taking some CPU cycles while the
backend is processing your query.  Also, depending on how the CPU load
is reported, if the OS is doing prefetching of I/O, it might show up as
load.

- Luke



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