Update O_DIRECT comment.

This commit is contained in:
Bruce Momjian 2005-07-29 03:25:53 +00:00
parent 5b63e7b467
commit c6b1724c67

View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.211 2005/07/29 03:22:33 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.212 2005/07/29 03:25:53 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -54,6 +54,8 @@
* with fsync(), but because skipping the kernel buffer forces writes out
* quickly, it seems best just to use it for O_SYNC. It is hard to imagine
* how fsync() could be a win for O_DIRECT compared to O_SYNC and O_DIRECT.
* Also, O_DIRECT is never enough to force data to the drives, it merely
* tries to bypass the kernel cache, so we still need O_SYNC or fsync().
*/
#ifdef O_DIRECT
#define PG_O_DIRECT O_DIRECT