[jetty-users] AbstractSessionIdManager blocking threads

[Stefan Magnus Landrø <stefan.landro@xxxxxxxxx>]

Hi there,

while performing some load testing of our web-application, we noticed that all of our threads got BLOCKED by synchronized in the following code in AbstractSessionIdManager

 public String newSessionId(HttpServletRequest request, long created)

    {

        synchronized (this)

        {

....

            while (id==null||id.length()==0||idInUse(id))

         

....

}

}

We're using the JDBCSessionIdManager, and since idInUse performs a sql call in our case, this won't perform well.

We tried using a hazelcast-based session id manager we found on github, but that too gets stuck (as in threads are BLOCKED) when the load is high enough.

The question now is, why is this code in a synchronized block? When using a jdbc-based session id manager, I believe it would make sense to rely on database mechanisms to ensure sessionids are not reused etc instead of using a synchronized block'.

Does anyone have any thoughts on this?

Cheers,

Stefan