In response to Sim Zacks : > > > On 03-Aug-2010 11:18 AM, A. Kretschmer wrote: > > In response to Sim Zacks : > > > >> Is there a way to tell what the optimal memory is for a specific > >> postgresql instance? > >> > >> I am configuring Xen virtual machines and I don't want to give it more > >> then it needs. > >> > >> Would looking at the swap be an indication? As soon as it starts to use > >> swap, that means I need more, but until that point, I have enough? > >> > > You can't have enough ;-) > > > > Fits your DB into the RAM? > > > > If you don't have enough, for instance, work_mem, sort-operations > > performed on disk and not in the ram. That's much slower. So, as i said, > > you can't have enough ram ;-) > > > In theory that's a great answer. ;-) > If my database is 400MB (du on the base directory) and there are 10 > active users running functions and queries, that for the most part take > less then 1 sec each. > I would assume that 10GB of RAM is overkill. Maybe. > Is 2 GB RAM also overkill? Is there a way to know when you have reached > the overkill level? I think, you should try it. Set your virtual machine to 2 GByte, set shared_buffers to 512 MByte, effective_cache_size to 1.5 gbyte and work_mem to, for instance, 20 mbyte. Monitor the machine, watch the logfile (set log_min_duration_statement properly). Reduce all parameters to 50% and compare the results. Andreas -- Andreas Kretschmer Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header) GnuPG: 0x31720C99, 1006 CCB4 A326 1D42 6431 2EB0 389D 1DC2 3172 0C99 -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
