Sean Chittenden wrote: > > > Nor could it ever be a win unless the cache was populated via > > > O_DIRECT, actually. Big PG cache == 2 extra copies of data, once > > > in the kernel and once in PG. Doing caching at the kernel level, > > > however means only one copy of data (for the most part). Only > > > problem with this being that it's not always that easy or an > > > option to reconfig a kernel to have a bigger FS cache. That said, > > > tripple copying a chunk of mem is generally faster than even a > > > single disk read. If PostgreSQL ever wanted to have a platform > > > agnostic way of doing efficient caching, it'd likely have to be in > > > the userland and would require the use of O_DIRECT. > > > > Actually, I think of O_DIRECT as platform-dependent. > > FreeBSD, IRIX, and AIX, implement it, and ... *smiles with pride* > looks like Linux does too given the number of security vulnerabilities > associated with the call. :-]
OK, that's 4 of 15 platforms. -- 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 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faqs/FAQ.html
