From: Bruce Momjian Date: Tue, 19 Oct 2010 15:49:53 +0000 (+0000) Subject: Add mention of using tools/fsync to test fsync methods. Restructure X-Git-Tag: REL8_4_6~31 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d94d0a8c83715cb403267f0c89068781b706ddff;p=postgresql Add mention of using tools/fsync to test fsync methods. Restructure recent wal_sync_method doc paragraph to be clearer. --- diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 76af829d2d..3aa74870f8 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -1458,13 +1458,15 @@ SET ENABLE_SEQSCAN TO OFF; Not all of these choices are available on all platforms. - The default is the first method in the above list that is supported - by the platform. The default is not necessarily best; it may be - necessary to change this setting, or other aspects of your system - configuration, in order to create a crash-safe configuration, as - discussed in , or to achieve best - performance. The open_* options also use O_DIRECT if available. + The default is the first method in the above list that is supported + by the platform. + The default is the first method in the above list that is supported + by the platform. The default is not necessarily ideal; it might be + necessary to change this setting or other aspects of your system + configuration in order to create a crash-safe configuration or + achieve optimal performance. + These aspects are discussed in . This parameter can only be set in the postgresql.conf file or on the server command line. diff --git a/doc/src/sgml/wal.sgml b/doc/src/sgml/wal.sgml index 36545e4e1a..f3ee6bb7a7 100644 --- a/doc/src/sgml/wal.sgml +++ b/doc/src/sgml/wal.sgml @@ -482,11 +482,13 @@ The parameter determines how PostgreSQL will ask the kernel to force - WAL updates out to disk. - With the exception of fsync_writethrough, which can sometimes - force a flush of the disk cache even when other options do not do so, - all the options should be the same in terms of reliability. - However, it's quite platform-specific which one will be the fastest. + WAL updates out to disk. + All the options should be the same in terms of reliability, with + the exception of fsync_writethrough, which can sometimes + force a flush of the disk cache even when other options do not do so. + However, it's quite platform-specific which one will be the fastest; + you can test option speeds using the utility src/tools/fsync + in the PostgreSQL source tree. Note that this parameter is irrelevant if fsync has been turned off.