Dear Damian, > I know nothing about this, but could 'removeAbandoned' be the issue?
> "If set to true a connection is considered abandoned and eligible for removal > if it has been idle longer than the removeAbandonedTimeout. Setting this to > true can recover db connections from poorly written applications which fail > to close a connection." > I suspect that just means the idle connection will be returned to the pool > (i.e. be made available on getConnection) rather than something more drastic, > however. Might be ... But I believe that lost connection is not the issue, as there is essentially a single connection used by our web app. If this one is "abandoned" and thus reclaimed by the pool, I would expect that the SDB/MySQL stack would complain about connection lost and not about a non-existing table. This brings me to conclusions that there must be essentially two threads/clients that access *the very same* connection concurrently. Maybe also transaction isolation issue ?!? > Does it happen after an extended period? Or can it happen almost immediately? Unfortunately, it is even problematic for us to reproduce the error ... seems like an issue that appears after a few days running the web app on the server, so not very early at all. This is the reason why I contacted this list, as an general insight into SDB might be helpful for us. Debugging is not a good strategy on our side, as it is nothing to debug most of the time ;-) > To be honest by default SDB will serialise threaded writes, so concurrent > access in unlikely to be the problem. Well this brings me back to the idea of a transaction isolation issue ... > They're not synchronised, but the effect is similar. Roughly, every jena > model corresponding to a store indirectly references that store and knows the > graph name (ignore the default graph here). Every model add becomes store add > (graph, s, p, o), in effect. These quads are added to a concurrent queue in > the loader, which waits for new items to be queued, and adds when available. > Queues are fine with multiple threads. Thanks for the info. If something comes to yr. mind, please let me know. Our problem is of urgent nature. Thanks for your help ! Petr -- The Open University is incorporated by Royal Charter (RC 000391), an exempt charity in England & Wales and a charity registered in Scotland (SC 038302).
