Re: How can I to solute this problem?

From: Paul Thomas <paul(at)tmsl(dot)demon(dot)co(dot)uk>
To: Achilleus Mantzios <achill(at)matrix(dot)gatewaynet(dot)com>
Cc: LEON <ldai(at)accunettech(dot)com>, "pgsql-sql (at) postgresql (dot) org" <pgsql-sql(at)postgresql(dot)org>
Subject: Re: How can I to solute this problem?
Date: 2003-07-29 12:37:03
Message-ID: 20030729133703.G25238@bacon
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On 29/07/2003 17:09 Achilleus Mantzios wrote:
>
> You may take a look at jboss connection pool
> mechanism. (postgresql.xml)

He doesn't mention JBoss, just Tomcat so I don't believe the
postgresql.xml will help him much. He could use Tomcat's built-in
connection pooling
(http://jakarta.apache.org/tomcat/tomcat-4.1-doc/jndi-datasource-examples-howto.html)
but should note that there is an error in the web.xml fragment:
<res-ref-name>jdbc/mydb</res-ref-name> should be
<res-ref-name>jdbc/postgres</res-ref-name>. Leon, if you need more help
please feel free to contact me off-list.

>
> Also a good way of ensuring that your app will
> not leave open stale postgresql connections
> is to initially configure your pool to only have a small
> number of connections (e.g. 2,3).

Good advice for any form of connection pooling.

>
> If your J2EE components (e.g. jsps) are fast enough
> you should start facing connection shortages
> only after the load on your machine increases
> significantly. (and then safely increase the maximum
> number of connections in your configuration (both postgresql wise
> and app server (conn pool) wise).
>
>
> On Tue, 29 Jul 2003, Paul Thomas wrote:
>
> >
> > On 29/07/2003 07:18 LEON wrote:
> > > I use tomcat+linux_postgresql+jsp to develop system.
> > >
> > > I start postgresql with 1024 processes.
> > > FE:
> > > postmaster -i -S -N 1024 -B 2048 -D /var/lib/pgsql/data
> > >
> > > My jsp doesn't implement connection pool.It directly connects
> postgresql
> > > by jdbc.
> >
> > IME, that is not a good way to do it. Use a connection pool.
> >
> > > After I run the Ui some times, the UI(jsp) would report "ieSorry,too
> many
> > > clientslg" .The exception is SQLException.
> > >
> > > I must restart tomcat or postgresql I can continue to running my UI.
> >
> > My guess would be that you have a bug in your application which is not
> > always closing the connection so eventually you exceed max_connections.
>
> > You should always close the connection in a finally{} block so that is
> > guaranteed that it will be closed regardless of any earlier exceptions
> > which are thrown.
> >
> > HTH
> >
> >
>
> --
> ==================================================================
> Achilleus Mantzios
> S/W Engineer
> IT dept
> Dynacom Tankers Mngmt
> Nikis 4, Glyfada
> Athens 16610
> Greece
> tel: +30-210-8981112
> fax: +30-210-8981877
> email: achill at matrix dot gatewaynet dot com
> mantzios at softlab dot ece dot ntua dot gr
>
>
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