Andrew - Supernews wrote: > On 2005-08-12, Alvaro Herrera <[EMAIL PROTECTED]> wrote: > > In light of this, may I ask whether it makes sense to compare the > > performance of two runs with similar shared_buffer settings? With > > O_DIRECT, I understand from this manpage that the OS is going to do > > little or no page caching, so shared_buffers should be increased to > > account for this fact. > > > > Am I missing something? > > O_DIRECT should only be being used for the WAL, not for buffer I/O.
And only when open_sync or open_datasync are used. But the group write patch is used in all cases, but again only WAL. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (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 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match