On Thu Dec 20, 2001 at 05:39:16PM -0500, Sam Varshavchik wrote: > >I think many of us using some database (ie. MySQL or LDAP) would really > >like to have authdaemond make use of the fact that he's persistant. > > It already does. It keeps a persistent database connection open.
I think that he already knows that... > >When it comes to tens or hundreds of queries per second, having some > >caching would save us some serious load on the database server(s). > > Before you design these kinds of grandiose schemes, try to do some analysis > first. Caching will only work if you get the same requests, over and over > again. It looks exactly like that, what a surprise ! Usually on a mail server 20% of the users makes 80% of the traffic... > Unless you have lusers that try to log in hundreds of times per > second, caching only adds unnecessary complexity, opportunities for more > bugs to fester around, and you won't end up saving anything since nearly > every request won't be found in the cache, and you end up going to the DB > anyway. Think of an user who gets hundreds of mails a day, because he might have subscribed to a lot of mailing lists, i don't think it's so uncommon... now imagine this user is not exactly alone on a medium to large size mailserver. On that kind of system, authdaemon will ask the database, for any given user, its uid, place to store mail, and a lot of other things you might know. All this happens each time it gets a mail... again and again... Let's examine a common situation: when i shut my small mailserver down a few minutes in order to perform maintenance tasks, mails are delivered to the secondary mx. When i restart the server, a lot of incoming mails are received at once and the server's load reaches 40 becauses of LDAP requests. When i look at the performed queries, i notice most of them are obviously duplicated. So how can I keep myself from sparing such unuseful requests ? Knowing this, I cannot see how I could say such a system is not usefull, I would say it's paramount. Of course, it's my point of view... > So, exactly what do you expect to get from caching, really? Heh ? making caffee ? :) -- ___________________________________________________________________________ O l i v i e r P o i t r e y _______________________________________________ courier-users mailing list [EMAIL PROTECTED] Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users
