postgresql/doc/src/sgml/pgtestfsync.sgml
Peter Eisentraut bb4eefe7bf doc: Improve DocBook XML validity
DocBook XML is superficially compatible with DocBook SGML but has a
slightly stricter DTD that we have been violating in a few cases.
Although XSLT doesn't care whether the document is valid, the style
sheets don't necessarily process invalid documents correctly, so we need
to work toward fixing this.

This first commit moves the indexterms in refentry elements to an
allowed position.  It has no impact on the output.
2014-02-23 21:31:08 -05:00

122 lines
3.4 KiB
Plaintext

<!-- doc/src/sgml/pgtestfsync.sgml -->
<refentry id="pgtestfsync">
<indexterm zone="pgtestfsync">
<primary>pg_test_fsync</primary>
</indexterm>
<refmeta>
<refentrytitle><application>pg_test_fsync</application></refentrytitle>
<manvolnum>1</manvolnum>
<refmiscinfo>Application</refmiscinfo>
</refmeta>
<refnamediv>
<refname>pg_test_fsync</refname>
<refpurpose>determine fastest wal_sync_method for <productname>PostgreSQL</productname></refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>pg_test_fsync</command>
<arg rep="repeat"><replaceable>option</replaceable></arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<application>pg_test_fsync</> is intended to give you a reasonable
idea of what the fastest <xref linkend="guc-wal-sync-method"> is on your
specific system,
as well as supplying diagnostic information in the event of an identified I/O
problem. However, differences shown by
<application>pg_test_fsync</application> might not make any significant
difference in real database throughput, especially since many database servers
are not speed-limited by their transaction logs.
<application>pg_test_fsync</application> reports average file sync operation
time in microseconds for each <literal>wal_sync_method</literal>, which can also be used to
inform efforts to optimize the value of <xref linkend="guc-commit-delay">.
</para>
</refsect1>
<refsect1>
<title>Options</title>
<para>
<application>pg_test_fsync</application> accepts the following
command-line options:
<variablelist>
<varlistentry>
<term><option>-f</option></term>
<term><option>--filename</option></term>
<listitem>
<para>
Specifies the file name to write test data in.
This file should be in the same file system that the
<filename>pg_xlog</> directory is or will be placed in.
(<filename>pg_xlog</> contains the <acronym>WAL</> files.)
The default is <filename>pg_test_fsync.out</> in the current
directory.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-s</option></term>
<term><option>--secs-per-test</option></term>
<listitem>
<para>
Specifies the number of seconds for each test. The more time
per test, the greater the test's accuracy, but the longer it takes
to run. The default is 5 seconds, which allows the program to
complete in under 2 minutes.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-V</></term>
<term><option>--version</></term>
<listitem>
<para>
Print the <application>pg_test_fsync</application> version and exit.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-?</></term>
<term><option>--help</></term>
<listitem>
<para>
Show help about <application>pg_test_fsync</application> command line
arguments, and exit.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1>
<title>Author</title>
<para>
Bruce Momjian <email>bruce@momjian.us</email>
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<simplelist type="inline">
<member><xref linkend="app-postgres"></member>
</simplelist>
</refsect1>
</refentry>