Mark Martinec wrote: > Grant, > > >> Anyway. I've done quite a bit of work recently on our front end filter >> - a custom developed greylist filter which uses data collected by >> amavisd to help decide what to 4XX and what to let through. More >> importantly I've just completed updating that filter to make extensive >> use of memcached (www.danga.com/memcached/) and wow what a difference >> it made to performance. >> >> I now want to look at whether memcached would work well with bayes and >> amavisd. Bayes in particular because I think it is the hardest hitting >> database app and amavisd because I'm about to start the upgrade process. >> > > I don't think Bayes is a bottleneck at all. Using MySQL InnoDB to hold > a Bayes db, it typically takes 15..35 ms for SpamAssassin to do its > bayes lookup, and maybe twice as much for an automatic 'learn' > (writing/updating records) when needed. Compared to the rest > it is pretty much negligible. >
Yes, but you are grinding your disk for those ms. When you do a write in mysql it flushes the query cache for that table, so basically the bayes tables never really cache well. I guess what was suggested is something like to write the changes out to the DB as normal, but use memcached as the coherent read cache across servers? The point here is that you you won't hit the DB for reads and have very fast lookups. I guess this doesn't change the load on the amavisd-new machine much , but it may make a huge difference on the DB machine for heavy users... Ed W ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ AMaViS-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/amavis-user AMaViS-FAQ:http://www.amavis.org/amavis-faq.php3 AMaViS-HowTos:http://www.amavis.org/howto/
