From f6d278364ea9441abc66b05f98e186df6907c76f Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 17 Sep 2004 22:40:46 +0000
Subject: [PATCH] Improve documentation of log rotation options, per Ed L.
---
doc/src/sgml/runtime.sgml | 41 ++++++++++++++++++++++++++++-----------
1 file changed, 30 insertions(+), 11 deletions(-)
diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index 1a2f24500f..2ca5e38018 100644
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -1,5 +1,5 @@
<!--
-$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.280 2004/08/31 04:53:43 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.281 2004/09/17 22:40:46 tgl Exp $
-->
<Chapter Id="runtime">
@@ -1929,16 +1929,16 @@ archive_command = 'copy "%p" /mnt/server/archivedir/"%f"' # Win32
<term><varname>log_filename</varname> (<type>string</type>)</term>
<listitem>
<para>
- When <varname>redirect_stderr</> is enabled, this option
+ When <varname>redirect_stderr</varname> is enabled, this option
sets the file names of the created log files. The value
- is treated as a <systemitem>strftime</> pattern,
- so <literal>%</>-escapes
+ is treated as a <systemitem>strftime</systemitem> pattern,
+ so <literal>%</literal>-escapes
can be used to specify time-varying file names.
- If no <literal>%</>-escapes are present,
+ If no <literal>%</literal>-escapes are present,
<productname>PostgreSQL</productname> will
append the epoch of the new log file's open time. For example,
- if <varname>log_filename</> were <literal>server_log</>, then the
- chosen file name would be <literal>server_log.1093827753</>
+ if <varname>log_filename</varname> were <literal>server_log</literal>, then the
+ chosen file name would be <literal>server_log.1093827753</literal>
for a log starting at Sun Aug 29 19:02:33 2004 MST.
This option can only be set at server start or in the
<filename>postgresql.conf</filename> configuration file.
@@ -1950,7 +1950,7 @@ archive_command = 'copy "%p" /mnt/server/archivedir/"%f"' # Win32
<term><varname>log_rotation_age</varname> (<type>integer</type>)</term>
<listitem>
<para>
- When <varname>redirect_stderr</> is enabled, this option
+ When <varname>redirect_stderr</varname> is enabled, this option
determines the maximum lifetime of an individual log file.
After this many minutes have elapsed, a new log file will
be created. Set to zero to disable time-based creation of
@@ -1965,7 +1965,7 @@ archive_command = 'copy "%p" /mnt/server/archivedir/"%f"' # Win32
<term><varname>log_rotation_size</varname> (<type>integer</type>)</term>
<listitem>
<para>
- When <varname>redirect_stderr</> is enabled, this option
+ When <varname>redirect_stderr</varname> is enabled, this option
determines the maximum size of an individual log file.
After this many kilobytes have been emitted into a log file,
a new log file will be created. Set to zero to disable size-based
@@ -1980,19 +1980,38 @@ archive_command = 'copy "%p" /mnt/server/archivedir/"%f"' # Win32
<term><varname>log_truncate_on_rotation</varname> (<type>boolean</type>)</term>
<listitem>
<para>
- When <varname>redirect_stderr</> is enabled, this option will cause
+ When <varname>redirect_stderr</varname> is enabled, this option will cause
<productname>PostgreSQL</productname> to truncate (overwrite),
rather than append to, any existing log file of the same name.
However, truncation will occur only when a new file is being opened
due to time-based rotation, not during server startup or size-based
rotation. When false, pre-existing files will be appended to in
all cases. For example, using this option in combination with
- a <varname>log_filename</> like <literal>postgresql-%H.log</>
+ a <varname>log_filename</varname> like <literal>postgresql-%H.log</literal>
would result in generating twenty-four hourly log files and then
cyclically overwriting them.
This option can only be set at server start or in the
<filename>postgresql.conf</filename> configuration file.
</para>
+ <para>
+ Example: To keep 7 days of logs, one log file per day named
+ <literal>server_log.Mon</literal>, <literal>server_log.Tue</literal>,
+ etc, and automatically overwrite last week's log with this week's log,
+ set <varname>log_filename</varname> to <literal>server_log.%a</literal>,
+ <varname>log_truncate_on_rotation</varname> to <literal>true</literal>, and
+ <varname>log_rotation_age</varname> to <literal>1440</literal>.
+ </para>
+ <para>
+ Example: To keep 24 hours of logs, one log file per hour, but
+ also rotate sooner if the log file size exceeds 1GB, set
+ <varname>log_filename</varname> to <literal>server_log.%H%M</literal>,
+ <varname>log_truncate_on_rotation</varname> to <literal>true</literal>,
+ <varname>log_rotation_age</varname> to <literal>60</literal>, and
+ <varname>log_rotation_size</varname> to <literal>1000000</literal>.
+ Including <literal>%M</> in <varname>log_filename</varname> allows
+ any size-driven rotations that may occur to select a filename
+ different from the hour's initial filename.
+ </para>
</listitem>
</varlistentry>
--
2.24.1