added:

From wiki Tue Mar 27 01:40:48 +1000 2007
From: wiki
Date: Tue, 27 Mar 2007 01:40:48 +1000
Subject: Problems when using sqlite
Message-ID: <20070327014048+1000@www.mechanicalcat.net>

When a single-user database backend (e.g. SQLite) is used, problems might occur because the database is locked when someone else tries to access it. Therefore it might be necessary to close the connection after use (untested):

    def close_db()
        global db
        db.close()
        db = None

    def useful_function(...):
        "no db argument required nor supported"
        global db
        check_db()
        try:
            # do the interesting stuff and, when writing,
            # don't forget to commit()...
            return interesting_data
       finally:
            close_db()

Just in case... I didn't suffer any problems myself.