Hi Chathuri,

Do you know how many hours it takes before connections are dropped?  Based
on your persistence.xml, it looks like you are using MySQL.  By default
MySQL connections will timeout after 8 hours of inactivity.  MySQL provides
a parameter "wait_timeout" that can be used to set the amount of time to
allow a non-interactive connection to site idle before closing it.

http://dev.mysql.com/doc/refman/5.0/en/server-system-variables.html#sysvar_wait_timeout

On the client, DBCP includes additional parameters that you can use to tune
the timeout and purge behavior of the connection pool.  A combination of
validationQuery, testWhileIdle, etc. may help clear idle connections that
have gone stale out of the pool (
http://commons.apache.org/proper/commons-dbcp/configuration.html) before
they get handed to OpenJPA.  I also checked on the MySQL driver and based
on the documentation, TCP keep alive should be enabled by default (
http://dev.mysql.com/doc/refman/5.0/en/connector-j-reference-configuration-properties.html)
and the socket timeout is 0 (no timeout) - so I wouldn't guess that the
driver is causing the time out.

hth,
-Jeremy


On Fri, Jun 7, 2013 at 3:02 PM, Chathuri Wimalasena <[email protected]>wrote:

> Hi Devs,
>
> In apache airavata project[1], we are using apache openJPA as the layer in
> front of our database. We have clients which run scientific jobs using
> apache airavata project and these jobs can be idle for several hours. In
> our openJPA configuration we are maintaining a connection pool. But it
> seems connection gets lost after several hours of idle time. Is there any
> property that we can maintain from openJPA configuration to make sure
> connection will not be lost after several hours of idle time ?
>
> FYI, I'm listing the openJPA configuration [2] and how the properties[3]
> ingested from a java class.
>
> Thanks and Regards,
> Chathuri
>
> [1] http://airavata.apache.org/
> [2]
>
> https://svn.apache.org/repos/asf/airavata/trunk/modules/registry/airavata-jpa-registry/src/main/resources/META-INF/persistence.xml
> [3]
>
> https://svn.apache.org/repos/asf/airavata/trunk/modules/registry/airavata-jpa-registry/src/main/java/org/apache/airavata/persistance/registry/jpa/ResourceUtils.java
>

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