Hi there,
Note you're working with db, how are you running your queries as to not block the main packet handler? Just hitting those with new threads or is your database access fairly limited?
Regards,
EDIT: Forgot to mention that I've also seen the above behavior when running in mono debug session. Haven't been able to get connectivity working though, moved out the standalone ot a windows vm which of course makes debugging awesome *not*. There again, debugging the master server without timing out your clients isn't an easy feat either. Looking at the code journal playback system code won't be easy to integrate.