ADOdb, the database library i maintain, has had support for storing session data in a database for a long time. However there was one limitation that always continued to bug me: the fact that all the PHP servers using database-backed sessions needed to synchronize their times to ensure that the session timers worked properly.

In the latest version of this popular library, his bothersome limitation is gone. The Session2 implementation uses the database server clock to track times.

This requires us to change the database table format used, but that is a small price to pay for the added flexibility. You can read more in the ADOdb session docs.