From: Bruce Momjian <bruce@momjian.us>
Date: Fri, 29 Jul 2005 03:25:53 +0000 (+0000)
Subject: Update O_DIRECT comment.
X-Git-Tag: REL8_1_0BETA1~218
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=c6b1724c672f7875f1eb58f22248ce1d2dfe4fa7;p=postgresql

Update O_DIRECT comment.
---

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index fc9264cfcd..3f393eb10d 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -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