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/*
* README
* mod_log_slow - Logging Slow Request Module for Apache1.3 and Apache2.X
*/
_ _ _
_ __ ___ ___ __| | | | ___ __ _ ___| | _____ __
| '_ ` _ \ / _ \ / _` | | |/ _ \ / _` | / __| |/ _ \ \ /\ / /
| | | | | | (_) | (_| | | | (_) | (_| | \__ \ | (_) \ V V /
|_| |_| |_|\___/ \__,_|___|_|\___/ \__, |___|___/_|\___/ \_/\_/
|_____| |___/_____|
====================================================================
* Introduction
====================================================================
mod_log_slow is Apache module to provide measures of the time period
used for handling each request by the current process. Logging is done
after processing a request if the request takes more than certain
period of time that you specifiy.
The idea of this module comes from MySQL's slow-query-log, and its
logging logic is partially based on mod_log_forensic.
====================================================================
* Download
====================================================================
http://code.google.com/p/modlogslow/downloads/list
====================================================================
* Build and Install
====================================================================
1) extract files from an archive
tar zxf modlogslow-<VERSION>.tar.gz
cd modlogslow-<VERSION>
2) open Makefile and modify ap_basedir variable
vi Makefile
ap_basedir=/PATH-TO-APACHE-BASE
3) make and install
make
sudo make install
====================================================================
* Configuration Directives
====================================================================
All the directives below may be specified as per-server configuration.
o LogSlowEnabled
Description: set "On" to enable log_slow, "Off" to disable.
Default "Off"
Syntax: LogSlowEnabled On/Off
Context: server config, virtual host
Status: Extension
Module: mod_log_slow
o LogSlowLongRequestTime
Description: Set the limit of request handling time in millisecond.
Default "1000". Logging is done after processing a request
if the request takes more than LogSlowLongRequestTime.
Syntax: LogSlowLongRequestTime number(millisecond)
Context: server config, virtual host
Status: Extension
Module: mod_log_slow
o LogSlowFileName
Description: Set the filename of the slow log. The SlowLogFileName
directive is used to log requests info that takes more than
the time period specified in LogSlowLongRequestTime directive.
Syntax: LogSlowFileName filename or pipe
Context: server config, virtual host
Status: Extension
Module: mod_log_slow
[note]
In case of using pipe("|"), followed by the path to a program to receive the log information on its standard input.
o LogSlowTimeFormat
Description: Set the time, in the form given by format, which should
be in strftime(3) format. The slow_log's log entries are written
in this format. If not set, the log entries are written in
Common Log Format(CLF) by default.
Syntax: LogSlowTimeFormat timeformat
Context: server config, virtual host
Status: Extension
Module: mod_log_slow
[example]
LogSlowTimeFormat "[%Y-%m-%d %H:%M:%S]"
-> [2009-06-24 00:09:44]
o LogSlowBufferedLogs
Description: set "On" to enable buffered logs flush, "Off" to disable.
Default "Off". Of cource if buffered logs option is set "On",
slow_log is written delayed so as to decrease disk io and thus
to lower the load. Only apache2 module supports.
Syntax: LogSlowBufferedLogs On/Off
Context: server config, virtual host
Status: Extension
Module: mod_log_slow
====================================================================
* Logging Format
====================================================================
Slow log entry is written to the file that specified in LogSlowFileName
directive, and the logging is made only after the request processing
that takes more than the time period specified in LogSlowLongRequestTime
directive.
1) Unique ID
mod_log_slow assigns a unique ID for each log entry, and the ID is
added to the log string. If you're using mod_unique_id, its generated
ID will be used as the unique ID.
2) Slow Log Format
<Unique ID> <time> elapsed: <elapsed time> cpu: <cpu usrtime>(usr)/<cpu systime>(sys) pic: <PID> ip: <REMOTE_IP> host: <HOSTNAME> reqinfo: <REQINFO>
o <Unique ID>
Description: the unique ID assigned for each log entry.
o <time> (CLF or User Defined Format)
Description: the time to occur the log entry.
o <elapsed time> (sec)
Description: the time took for the request processing.
o <cpu usrtime> (sec)
Description: cpu user time used for the request processing.
o <cpu systime> (sec)
Description: cpu sys time used for the request processing.
o <PID>
Description: the process ID of apache child process.
o <REMOTE_IP>
Description: the request's remote ip address.
o <HOSTNAME>
Description: the request's hostname.
o <REQINFO>
Description: the request information string.
Format: <METHOD> <PATH> <PROTOCOL>
ex. reqinfo: GET /wiki/index.html?foo=val1&bar=val2 HTTP/1.0
log example)
3f2b:4a40e871:0 [23/Jun/2009:23:36:33 +0900] elapsed: 0.15 cpu: 0.05(usr)/0.00(sys) pid: 16171 ip: 127.0.0.1 host: localhost:80 reqinfo: GET /wiki/index.html?foo=val1&bar=val2 HTTP/1.0
3) Apache Note Info and CustomLog Format
mod_log_slow adds 2 records below in apache request_rec's 'notes'
table when the request processing time is slow enough for the slow
logging to be make.
o Unique ID
Description: the unique ID assigned for each log entry.
Name: "logslow-id"
o Elapsed time
Description: the time took for the request processing.
Name: "logslow-time"
Therefore, you can add the unique ID and the elapsed time info to
the "CustomLog" by adding the %{logslow-id}n, %{logslow-time}n string
to log format string of CustomLog directive.
ex.
CustomLog logs/clicklog "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" \"%{logslow-id}n\" \"%{logslow-time}n\""
====================================================================
* Sample Configuration
====================================================================
1) load module
LoadModule log_slow_module modules/mod_log_slow.so
2) add directives below
LogSlowEnabled On
LogSlowLongRequestTime 100
LogSlowFileName /path-to-log/slow_log
LogSlowTimeFormat "[%Y-%m-%d %H:%M:%S]"
LogSlowBufferedLogs On
see also: sample.conf
====================================================================
* Authors
====================================================================
Yoichi Kawasaki <yokawasa@gmail.com>
|
