On Thu, Oct 10, 2013 at 5:02 AM, Bruce Momjian <br...@momjian.us> wrote: > On Wed, Oct 9, 2013 at 07:33:46PM -0700, Peter Geoghegan wrote: >> I hear a lot of complaints about "the first 15 minutes experience" of >> Postgres. It's easy to scoff at this kind of thing, but I think we >> could do a lot better there, and at no real cost - the major blocker >> to doing something like that has been fixed (of course, I refer to the >> SysV shared memory limits). Is the person on a very small box where >> our current very conservative defaults are appropriate? Why not ask a >> few high-level questions like that to get inexperienced users started? >> The tool could even have a parameter that allows a packager to pass >> total system memory without bothering the user with that, and without >> bothering us with having to figure out a way to make that work >> correctly and portably. > > I think the simplest solution would be to have a parameter to initdb > which specifies how much memory you want to use, and set a new variable > available_mem from that, and have things auto-tune based on that value > in the backend.
I think it would be even simpler, and more reliable, to start with the parameter to initdb - I like that. But instead of having it set a new variable based on that and then autotune off that, just have *initdb* do these calculations you're suggesting, and write new defaults to the files (preferably with a comment). That way if the user *later* comes in and say changes shared_buffers, we don't dynamically resize the work_mem into a value that might cause his machine to die from swapping which would definitely violate the principle of least surprise.. -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
