webspehere 6.0.1 throws javax.resource.ResourceException: The back-end resource is currently unavailable

Question

We have our application deployed to WAS 6 cluster. And recently it is throring following exception.

javax.resource.ResourceException: The back-end resource is currently unavailable. Stuck connections have been detected. ......

Can somebody explain me why db connection was not released by the app and came back to free pool? How can I detect what is blocking connection to be released? I am planning to take thread dump every fee secs.

Everything was working fine and all of a sudden we started getting this exception, which is causing an issue with new user who is trying to login into the app.

Any input will be greatly appreciated. I have very little knowledge about WAS admin.

Thanks

Answer 1

Try using the PMI within the WAS console under Monitoring and Tuning, this will allow you to trace both the JDBC and thread pool usage in real time, I would definitely pay close attention to the WebContainer pool and see if the size of the pool tracks with the JDBC connection.

If the pools themselves are becoming exhausted you can increase the size to provide some legroom by upping the Maximum Connection Settings for the JDBC connection under Resources -> Data Sources -> $NAME -> Connection Pool, and the other connection pool settings under Server -> $SERVERNAME -> Additional Properties -> Thread Pool

Ensuring that the database your connecting to also has sufficent free connections would also be an idea! :)

If you are leaking pool connections, then its likely the code is missing a close connection somewhere.