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. -- 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
