You set shared_buffers way below what is suggested in Greg Smith book (25% or more of RAM) .. what is the rationale behind that rule of thumb ? Other values are more or less what I set, though I could lower the effective_cache_size and vfs.zfs.arc_max and see how it goes.
Sébastien On Wed, Sep 12, 2012 at 7:24 PM, John R Pierce <pie...@hogranch.com> wrote: > On 09/12/12 4:03 PM, Sébastien Lorion wrote: > >> I agree 1GB is a lot, I played around with that value, but it hardly >> makes a difference. Is there a plateau in how that value affects query >> performance ? On a master DB, I would set it low and raise as necessary, >> but what would be a good average value on a read-only DB with same spec and >> max_connections ? >> > > a complex query can require several times work_mem for sorts and hash > merges. how many queries do you expect to ever be executing > concurrently? I'll take 25% of my system memory and divide it by > 'max_connections' and use that as work_mem for most cases. > > on a large memory system doing dedicated transaction processing, I > generally shoot for about 50% of the server memory as disk cache, 1-2GB as > shared_buffers, 512MB-2GB as maintenance_work_mem, and 20-25% as work_mem > (divided by max_connections) > > > > > -- > john r pierce N 37, W 122 > santa cruz ca mid-left coast > > > > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/**mailpref/pgsql-general<http://www.postgresql.org/mailpref/pgsql-general> >
