Re: Major Performance decrease after some hours

2006/10/1, Chris Mair <chrisnospam(at)1006(dot)org>:
> Hi,
>
> a few random question...
>
> > > i have a Tomcat application with PostgreSQL 8.1.4 running which
> > > performs about 10000 inserts/deletes every 2-4 minutes and updates on
> > > a database and after some hours of loadtesting the top output says
> > > 0.0% idle, 6-7% system load, load average 32, 31, 28
>
> Who is responsible for this high load values?
> Do you see many postmaster processes at the top?

yes, there are about 10 postmaster processes in top which eat up all
of the CPU cycles at equal parts.

> > and there are
> > > many exceptions at statement execution like:
> > > An I/O error occured while sending to the backend.
>
> Is this from the application?

Yes, this happens when the sql statements are executed.

> How many connections does the application open in parallel?

30-40, one tomcat runs on the same machine as PostgreSQL, another runs
on the other cluster and uses the database via network.

> Using JDBC, I guess?

yes, postgresql-8.1-407.jdbc3 is used

> > > - Each Cluster has 4 drbd Devices, one for the PostgreSQL data
> > > - Two of these clusters are using the same PostgreSQL installation to
> > > share the data, the database can be moved from one cluster to the
> > > other in case of failure
>
> Just to be 100% sure: just one server at a time runs PostgreSQL on
> that shared data disk, right?

One server of a cluster runs the database and the tomcat, the other
one just runs tomcat, so they share this common database.

> Bye,
> Chris.

thx,
Peter