Today the webapp went into a tailspin several times, and had to be restarted, only to die again. It looks like hundreds of sessions were being started on the local host as soon as the app started up, freezing it. Eventually it seemed to clear itself, but nothing in the logs looks like it was causing this problem. We still don't know what it was, but presumably not a DOS or an ill-behaved robot. Something weird in eXist.