Expiring user sessions on mysql

For RT 3.7, we have a proper session expirey mechanism, but the
following little script, run from cron will blow away any sessions in
your mysql rt3 session database every 15 minutes:

mysql rt3 -u root -e ’ delete from sessions where LastUpdated < from_unixtime( unix_timestamp()-(60*15));’

And yes, this is a hack, but it should work.