[Mimedefang] Bayes locking
David F. Skoll
dfs at roaringpenguin.com
Wed Oct 6 12:32:31 EDT 2004
On Wed, 6 Oct 2004, Paul Murphy wrote:
> the whole area of database locking for Bayes and AWL is a mess.
Indeed. :-)
But doesn't SA 3.0 support flock()-style locking? (I haven't looked at
the code.)
> The solution is to use a proper database - the latest SA has support
> for MySQL, which will be much more stable and on large databases
> will also probably be faster.
Pros and cons. I'm not sure I consider MySQL to be a "proper"
database. :-) (We use PostgreSQL in our commercial products, though it
has its annoyances too.) PostgreSQL actually uses MVCC rather than
locking, so readers are never blocked by a writer.
However, any semi-decent SQL database probably has a more robust
locking mechanism than SA's Perl code, and has the huge advantage of
being easily shared among several mail scanners. I think a Berkeley
DB will still beat a SQL database quite handily for raw data access
(at least for the access patterns used to look up Bayes tokens.)
Regards,
David.
More information about the MIMEDefang
mailing list