From c6b1724c672f7875f1eb58f22248ce1d2dfe4fa7 Mon Sep 17 00:00:00 2001 From: Bruce Momjian Date: Fri, 29 Jul 2005 03:25:53 +0000 Subject: [PATCH] Update O_DIRECT comment. --- src/backend/access/transam/xlog.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) 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 -- 2.40.0