On 8 Prosinec 2011, 14:17, Craig Ringer wrote: > You can. > > ALTER USER username SET work_mem = '100MB'; > > It's not a hard cap - the user can raise/lower it however they like. The > initial value can be set globally, per-user, per-database, or globally. Oh, shame on me! I wasn't aware of this. Too bad it's not possible to restrict this (changing certain config values). A simple 'before SET' hook might do the trick. >> I wonder if the prioritisation could be done using nice - each backend >> is a separate process, so why not to do 'nice(10)' for low priority >> processes or something like that. > > Yes, to a limited degree you can prioritise queries using nice and > ionice, but it's awkward because: > > - All queries run as `postgres' so you can't do per-user limiting very > easily > > - The postmaster doesn't have a way to set the nice level and ionice > level when it forks a backend, nor does the backend have any way to do > it later. You can use your own user-defined C functions for this, though. Yes, that's what I meant. > - Most importantly, even if you nice and ionice using C functions or > manually with the cmdline utilities, you can't affect the bgwriter, nor > can you affect how much data a low-priority query pushes out of cache. IMHO bgwriter may be reasonably tuned by bgwriter_* GUC variables. The user backends are probably more interesting here. Tomas -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
