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<chapter id="maintenance">

you can send a <literal>SIGHUP</literal> signal to the

<application>syslog</> daemon whenever you want to force it to

start writing a new log file. If you want to automate log

rotation, the <application>logrotate</application> program can be

rotation, the <application>rotatelogs</application> program can be

configured to work with log files from

<application>syslog</application>.

</para>

pipe command:

<programlisting>

pg_ctl start |logrotate

pg_ctl start |rotatelogs /var/log/pgsql_log 86400

</programlisting>

The <productname>PostgreSQL</> distribution doesn't include a

suitable log rotation program, but there are many available on the

Internet. For example, the <application>logrotate</application>

Internet. For example, the <application>rotatelogs</application>

tool included in the <productname>Apache</productname> distribution

can be used with <productname>PostgreSQL</productname>.

</para>

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server is started in the background, and standard input is attached to

<filename>/dev/null</filename>. The standard output and standard

error are either appended to a log file (if the <option>-l</option>

option is used), or redirected to<application>pg_ctl</application>'s

option is used), or redirected to <application>pg_ctl</application>'s

standard output (not standard error). If no log file is chosen, the

standard output of <application>pg_ctl</application> should be redirected

to a file or piped to another process, for example a log rotating program,

otherwise <command>postmaster</command>will write its output to the controlling

terminal (from the background) and will not leavetheshell's

process group.

to a file or piped to another process such as a log rotating program

like <application>rotatelogs</>;otherwisethe<command>postmaster</command>

will write its output to the controlling terminal (fromthebackground)

and will not leave the shell'sprocess group.

</para>

<para>