From 253fa736b978f298746763ef3113282f32b9f475 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Wed, 10 Dec 2008 11:05:49 +0000
Subject: [PATCH] Update journaling performance docs based on comments by
Michael Renner.
---
doc/src/sgml/wal.sgml | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/doc/src/sgml/wal.sgml b/doc/src/sgml/wal.sgml
index 3b013746a31..e69463a9e22 100644
--- a/doc/src/sgml/wal.sgml
+++ b/doc/src/sgml/wal.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/wal.sgml,v 1.54 2008/12/06 21:34:27 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/wal.sgml,v 1.55 2008/12/10 11:05:49 momjian Exp $ -->
<chapter id="wal">
<title>Reliability and the Write-Ahead Log</title>
@@ -139,13 +139,13 @@
<para>
Because <acronym>WAL</acronym> restores database file
contents after a crash, it is not necessary to use a
- journaled filesystem; in fact, journaling overhead can
- reduce performance. For best performance, turn off
- <emphasis>data</emphasis> journaling as a filesystem mount
- option, e.g. use <literal>data=writeback</> on Linux.
- Meta-data journaling (e.g. file creation and directory
- modification) is still desirable for faster rebooting after
- a crash.
+ journaled filesystem for reliability. In fact, journaling
+ overhead can reduce performance, especially if journaling
+ causes file system <emphasis>data</emphasis> to be flushed
+ to disk. Fortunately, data flushing during journaling can
+ often be disabled with a filesystem mount option, e.g.
+ <literal>data=writeback</> on a Linux ext3 file system.
+ Journaled file systems do improve boot speed after a crash.
</para>
</tip>
--
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