2009/7/23 Clunk Werclick <clunk.wercl...@wibblywobblyteapot.co.uk>: > That is a comfort to know. My main concern was this hammering was not > optimal, but it is welcome to make as many queries as it likes if it > does not crash the database server. Perhaps Postgresql would be a bit > more manly ? but slower ?
Realistically you shouldn't notice a difference, but every system will be different, and between those two it'll depend somewhat on tuning as well. > to disable parent domain searching'. I would like to do this and see if > it makes a difference. What do I need to take out/add to do this ? You can do this in main.cf, I believe you just set an empty value. http://www.postfix.org/postconf.5.html#parent_domain_matches_subdomains Something like: parent_domain_matches_subdomains = > It is not ideal to use it but it makes it easy to write web front ends > for management. I could script the generation of index postmaps from the > database but will this scale well? How big can the postmaps be before it > gets a little crazy? 100 lines? 1000 lines? 10,000 lines? 100,000 lines? > I cannot find any figures to say at which point it is best to cross > over ? This would be very useful and help me make an informed choice. Anecdotally, hash-based tables are "very fast". CDB tables are said to perform well at least up to a million entries. http://www.postfix.org/DATABASE_README.html#types > And this also. I don't think there is any major benefit being sold to me > here for using a proxy map and I am wondering if this will introduce a > small amount of latency perhaps? It's true that there's some latency involved, but the benefit it gives is that it consolidates the number of open connections to the database. This is a fairly common problem on setups with mysql when the system gets busy - it will open a lot of separate connections, and this can hit the configured limits, which causes things to fail (postfix can't connect to the database, so lookups fail). There are some (specific) lookup types that can't take proper advantage of proxymap, so they get handled correctly and silently (bypassing the proxymap service). There was some discussion about this a little while ago, but the outcome was that the potential performance gain of not using proxymap when it's not needed was low, so you might as well always use it. Of course, the best way to know is to try it for yourself. :)
