2013/10/9 Bruce Momjian <br...@momjian.us> > On Wed, Oct 9, 2013 at 04:32:44PM +0200, Andres Freund wrote: > > On 2013-10-09 10:30:46 -0400, Bruce Momjian wrote: > > > Josh Berkus suggested here that work_mem and maintenance_work_mem could > > > be auto-tuned like effective_cache_size: > > > > > > http://www.postgresql.org/message-id/50eccf93.3060...@agliodbs.com > > > > > > The attached patch implements this, closely matching the default values > > > for the default shared_buffers value: > > > > There imo is no correlation between correct values for shared_buffers > > and work_mem at all. They really are much more workload dependant than > > anything. > > Well, that is true, but the more shared_buffers you allocate, the more > work_mem you _probably_ want to use. This is only a change of the > default. > > Effectively, if every session uses one full work_mem, you end up with > total work_mem usage equal to shared_buffers. > > We can try a different algorithm to scale up work_mem, but it seems wise > to auto-scale it up to some extent based on shared_buffers. >
In my experience a optimal value of work_mem depends on data and load, so I prefer a work_mem as independent parameter. maintenance_work_mem can depend on work_mem ~ work_mem * 1 * max_connection / 4 Regards Pavel > > -- > Bruce Momjian <br...@momjian.us> http://momjian.us > EnterpriseDB http://enterprisedb.com > > + Everyone has their own god. + > > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers >
