Keep in mind that if we auto-tune, we will only be able to do it for some platforms, so we will need a table that shows which settings are autotuned for each platform.
--------------------------------------------------------------------------- Sean Chittenden wrote: > > I don't have much to add because I'm pretty new to Postgres and have > > been soliciting advice here recently, but I totally agree with > > everything you said. I don't mind if it's in the postgres.conf file > > or in a faq that is easy to find, I just would like it to be in one > > place. A good example of the need for this is when I was tuning > > "effective_cache" I thought that was creating a cache for Postgres > > when in fact as it was pointed out to me, it's just hinting to > > postgres the size of the OS cache. Lots of ways for people to get > > really confused here. > > I looked through the src/doc/runtime.sgml for a good place to stick > this and couldn't find a place that this seemed appropriate, but on > FreeBSD, this can be determined with a great deal of precision in a > programmatic manner: > > echo "effective_cache_size = $((`sysctl -n vfs.hibufspace` / 8192))" > > The same OID is available via C too. It'd be slick if PostgreSQL > could tune itself (on FreeBSD) at initdb time with the above code. If > Linux exports this info via /proc and can whip out the appropriate > magic, even better. An uncommented out good guess that shows up in > postgresql.conf would be stellar and quite possible with the use of > sed. > > Maybe an initdb switch could be added to have initdb tune the config > it generates? If a -n is added, have it generate a config and toss it > to stdout? > > > case `uname` in > "FreeBSD") > echo "effective_cache_size = $((`sysctl -n vfs.hibufspace` / 8192))" > ;; > *) > echo "Unable to automatically determine the effective cache size" >> > /dev/stderr > ;; > esac > > > -sc > > -- > Sean Chittenden > > ---------------------------(end of broadcast)--------------------------- > TIP 4: Don't 'kill -9' the postmaster > -- Bruce Momjian | http://candle.pha.pa.us [EMAIL PROTECTED] | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
