session.py 文件源码

def ping_listener(dbapi_conn, connection_rec, connection_proxy):
    """
    Ensures that MySQL connections checked out of the
    pool are alive.

    Borrowed from:
    http://groups.google.com/group/sqlalchemy/msg/a4ce563d802c929f
    """
    try:
        dbapi_conn.cursor().execute('select 1')
    except dbapi_conn.OperationalError, ex:
        if ex.args[0] in (2006, 2013, 2014, 2045, 2055):
            LOG.warn('Got mysql server has gone away: %s', ex)
            raise DisconnectionError("Database server went away")
        else:
            raise