We are trying to perform several table updates within a transaction, where some of the tables are in one database and some are in a second database, but it seems to be breaking the transaction commit call, and throws an exception. Is it possible to do this? If so, is there something special that needs to be set? I read somewher that this might have to do with using a thread-safe PHP. Is there truth in that? Any help or leads would be appreciated. I have searched the docs, SO and this forum without much success.