From: Chris Mair <list@1006.org>
To: Olivier Andreotti <olivier.andreotti@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Benchmarck PostgreSQL 8.1.4 MySQL 5.0.20 and Oracle
Date: Thu, 18 May 2006 14:44:40 +0200
Message-ID: <1147956280.9324.7.camel@dell.home.lan> (raw)
In-Reply-To: <d5d40b330605180342o1dc6013fue0b5d678a861c9b5@mail.gmail.com>
References: <d5d40b330605180257w2a0cb2dei53d81cbe0d7405e@mail.gmail.com>
<1147947373.7943.35.camel@dell.home.lan>
<d5d40b330605180342o1dc6013fue0b5d678a861c9b5@mail.gmail.com>
> > Could you give us some more infos about the box' performance while you
> > run the PG benchmark? A few minutes output of "vmstat 10" maybe? What
> > does "top" say?
>
> >
> Here, an extract from the vmstat 3 during the test, you can see that
> my problem is probably a very high disk usage (write and read).
>
> procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
> r b swpd free buff cache si so bi bo in cs us sy id wa
> 0 11 92 128344 9224 2428432 0 0 287 9691 2227 685 4 3 0 93
> [...]
Yes, as is the case most of the time, disk I/O is the bottleneck here...
I'd look into everything disk releated here...
> > How are you using the 3 disks? Did you split pg_xlog and the database
> > on different disks or not?
> >
>
> Data are on disk 1 et 2. Index on disk 3. Perhaps i'm wrong but fsync
> = off, pg_xlog are running with that ?
Yes, pg_xlog ist also used with fsync=off. you might gain quite some
performance if you can manage to put pg_xlog on its own disk (just
symlink the directory).
Anyway, as others have pointed out, consider that with fsync = off
you're loosing the "unbreakability" in case of power failures / os
crashes etc.
> > Can you say something about the clients? Do they run over network from
> > other hosts? What language/bindings do they use?
> >
>
> Client is another server from the same network. Clients are connected
> with JDBC connector.
ok, don't know about that one..
> > When they do inserts, are the inserts bundled or are there
> > single insert transactions? Are the statements prepared?
> I use prepared statements for all requests. Each transaction is about
> 5-45 requests.
sounds ok,
could be even more bundled together if the application is compatible
with that.
Bye, Chris.
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To: pgsql-performance@postgresql.org
Cc: list@1006.org, olivier.andreotti@gmail.com
Subject: Re: Benchmarck PostgreSQL 8.1.4 MySQL 5.0.20 and Oracle
In-Reply-To: <1147956280.9324.7.camel@dell.home.lan>
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