On Fri, Feb 26, 2010 at 11:49 AM, Jorge Montero <jorge_mont...@homedecorators.com> wrote: > > >>>> Tory M Blue <tmb...@gmail.com> 02/26/10 12:52 PM >>> >>> >>> This is too much. Since you have 300 connections, you will probably swap >>> because of this setting, since each connection may use this much >>> work_mem. The rule of the thumb is to set this to a lower general value >>> (say, 1-2 MB), and set it per-query when needed.
> > 1-2MB is good enough for many families of queries, but it's hard to say what > the right default should be for you. The right number can be estimated by > running explain analyze on your most common queries, with parameters that are > representative to regular use, and see how much memory they actually claim to > use. In my case, for example, most of my queries do just fine with 10 MB, > while the reporting queries that accumulate quite a bit of deta request up to > 60MB. > > If your average query needs 100 MB, it'd still mean that 40 connections take > 4 gigs worth of work memory, which might be better spent caching the database. Ya my boxes are pretty well stacked, but a question. How does one get the memory usage of a query. You state to look at explain analyze but this gives timing and costs, but is one of the numbers memory or do I have to take values and do some math? -------------------------------------------------------------------------------------------------------------------------- Function Scan on listings_search (cost=0.00..260.00 rows=1000 width=108) (actual time=904.374..904.383 rows=10 loops=1) Total runtime: 904.411 ms Thanks Tory Also don't think this 5 second thing is the DB.. Sure is not checkpoints. -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
