Thanks, 

I think Fastrack will do for now. :-)


mtgglf

Nils


 

-----Original Message-----
From: Martin Kal�n [mailto:[EMAIL PROTECTED] 
Sent: Wednesday, June 01, 2005 7:12 PM
To: OJB Users List
Subject: Re: Deep down

Nils Liebelt wrote:
> I get a wired Exception thrown by a OJB application seems like 
> something deep out of the MySQL JDBC.
<snip/>
> The error only occures when the system isn't answering any request for 
> a while.
<snip/>
> java.sql.SQLException: Communication link failure: 
> java.io.EOFException,

You are probably missing a validation query to check if the pooled
Connection objects have a live communication link to the database.

If 'something' makes the link drop (eg MySQL drops the connection due to
inactivity timeout - Oracle RDMBS does this, but I'm not sure if MySQL can
be configured in a similar fashion, or the network connectivity has gone
down and up again) the Connection object that OJB checks out from the pool
will have no TCP/IP connection to your database and you will get this
"communication link failure".

This is a problem/feature of any JDBC connection pool, so the answer apply
to applications other than OJB as well.

Fast-track answer:
  Change your connection-pool settings in repository_database.xml and
  make sure to include testOnBorrow="true" and validataionQuery="SELECT 1".

See here for a recent longer discussion regarding this:
  http://www.mail-archive.com/[email protected]/msg13521.html

Regards,
  Martin


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