On Mon, Jun 13, 2011 at 12:40:14PM +0200, Jean-Christophe Deschamps scratched on the wall: > > >As was being discussed yesterday, I have four processes accessing the > >same database file. When they perform an sqlite action, I wish them to > >block if the DB is not available. SQLite does not block if it finds the > >db busy or locked, it returns an error code. > > You can have SQLite do all this by itself, I mean without any extra > code. I've found this is the easiest way to handle the situation. > > Invoke sqlite3_busy_timeout() with a safe timeout for every connection > to the DB. > Use IMMEDIATE transactions everywhere. > > That's all you have to do.
Well, yes and no. You still have to deal with the case of SQLITE_BUSY being returned due to deadlocks. Setting a timeout and using BEGIN IMMEDIATE will help significantly, but not completely eliminate this issue. It also means that if an SQLITE_BUSY does slip through, you have no choice but to rollback the transaction and start all over. For more specifics, see: http://sqlite.org/lockingv3.html http://sqlite.org/c3ref/busy_handler.html <= deadlock info http://sqlite.org/c3ref/busy_timeout.html -j -- Jay A. Kreibich < J A Y @ K R E I B I.C H > "Intelligence is like underwear: it is important that you have it, but showing it to the wrong people has the tendency to make them feel uncomfortable." -- Angela Johnson _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
