We are a Wicket shop and for one of our clients have been running a Wicket application successfully for over 2 years. We are now at version 1.4.0. The traffic on the system is increasing and we are now seeing an increased frequency of pagemap locking which is beginning to be a serious problem for the users. By subclassing WebRequestCycle we have identified that a StackOverflowError under serialization in RequestCycle.detach() leaves the pagemap locked for the next minute. If our analysis is correct this is essentially the problem reported as https://issues.apache.org/jira/browse/WICKET-2075. Unfortunately we cannot reproduce the problem in our test environment and it occurs only in about one in every thousand requests with no apparent consistent pattern about what the user has been doing. Can anybody suggest an immediate strategy for further investigations? In particular:
- is there a practical way to find out what is causing the serialization problem. The stack trace is no help. We do in many cases have large amounts of data in the session, but doubling the default stack size leaves the problem frequency unchanged leading us to suspect a logical error rather the sheer amount of data. - by overriding RequestCycle.detach() and catching the StackOverflowError we can get control when the error occurs. Is there any way we can persuade Wicket to release the pagemap lock? I have looked at the code and this doesn't look straightforward. - can we get Wicket itself to suppress the StackOverflowError so that detach() continues and releases the lock? Grateful for any suggestions. Nigel --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
