RE: smp , php and postmaster distant

Performance degradations may also be due to lacking a daily "vacuum analyze;", which tells the optimizer how it should work.

Nicolas Huillard

-----Message d'origine-----
De: Chris Albertson [SMTP:calbertson(at)logicon(dot)com]
Date: jeudi 22 juin 2000 20:28
À: Dana Hudes
Cc: Loïc TREGOUËT; pgsql-admin(at)postgresql(dot)org
Objet: Re: smp , php and postmaster distant

Dana Hudes wrote:
<snip>
> Your gain from SMP under such situation is the application has a cpu for itself
> and all the system overhead processes run on the other cpu.

The above is correct, but Postgresql uses one process per connection.
This is a (possibly crude) from for multi threading. But it is the same
way the web server works. The process is forked. In the systems I've seen
it is common to have four to eight simultaneous open connections to
the database. Multiple CPUs _do_ help in this case.

The question below is hard to answer. If I read it correctly he is asking
"Why is performance go down when I switched to a dual CPU system?" He does
not provide detailed information about the configuration of his system both
before and after the change so we can't answer. Perhaps he had fsync disabled
then but no now. Who knows? A lot more detail is required.

My point is one more that with Postgresql, multiple CPUs can help if you have
multiple active clients.

> > Hie ,
> >
> >
> > I have put a database on a 2 processors db server . (2 * PII 450 Mhz
> > with 512 Mo RAM)
> >
> > This server is distant from the web server .
> >
> > I've a php3 interface and , i've seen some big loose of performance
> > .
> >
> > The request are longer when i use the bi-processor .
> >
> > Is it due to the distant server or do i need some configurations to
> > postmaster to accept multi prcocessors ?
> >
> > The web server and the database server are link with a 100Mbit link
> > !
> >
> > thanks for
> > all

--
Chris Albertson

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