We're upgrading an app from 2.8.11 to 3.0.7 and are seeing fairly frequent "database is locked" errors that would be explained if this were not the case. It seems to be happening when two threads start a transaction; one does its first INSERT ok but the second one gets a SQLITE_BUSY error when it tries to INSERT.
Our busy timeout is set high (several minutes) so it's pretty obvious that the timeout handler doesn't seem to be kicking in. What I would like is for the second thread to block until the first one commits i.e. 2.8.11 behaviour. I don't know the SQLite code so well but given that the busy timeout handler is invoked at the pager level, maybe this is why (i.e. because no pages are being changed, the handler is not being called).
