anonymous wrote : | I'm familiar with <check-valid-connection-sql>. The point of this exception-sorter exercise is to get away from the high expense of that approach. Ideally, we want to accept the cost of a single failure - followed by immediate invalidation of the pool - rather than the overhead of very frequent connection checks. | There is no notion of a 'purge policy' in JBoss as this time where the pool is invalidated based on the error state of a *single* failing connection. There is some debate on including this for a future release. JBoss 4.0.5 includes a background validation mechanism to evaluate pooled connections in the background rather than on retrieval which alleviates the overhead of constant validation. anonymous wrote : | The distinction between XA errors and connection errors is an artifact of how the XA transactions are managed. | The difference is simply in the origin of the exception. XA based errors are reported from the underlying XA resource which don't currently have a hook to evaluate the error. Again, there is no reason why this couldn't be added. As for the underlying MC being null, there are a few things that could cause this 1) The connection has been closed and you attempt to reuse the handle 2) The connection has been closed in another thread, and you attempt to reuse the handle 3) You are attempting to reuse the connection across method calls in an EJB and you do not have the spec compliant attribute set to true on the CachedConnectionManager (you would never really want to do this anyway). 4) You are not using connection validation and you have been given an invalid connection from the pool (this would be my guess). However, I am not seeing this in the stacktrace you posted. If the MC was actually null, you would never be able to execute a prepared statement, we check for this prior to every invocation to prohibit this behavior. I apologize if I am not looking in the right place. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4034225#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...