The Log4Net mailing list is a great source of information about using log4Net, in this forum we collect all the messages in the log4net user list and some selected threads from the developer list.
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Graham Walsh
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| 02/25/2009 2:33 PM |
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Hi,
I just switch from DEBUG to INFO in our application logging and the
difference is pretty much stunning. E.G. our perf has gone from 23
seconds down to 14 because of the change. Is this a known issue. i.e.
debug log level is expected to impose this kind of overhead.
Thanks
Graham
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Walden H. Leverich
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| 02/25/2009 3:31 PM |
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Graham,
That's not a log4net issue as much as it's an issue in your application.
Sounds like your application (like many) makes lots of log.Debug()
calls, to log, um, debug information. By switching the logging from
DEBUG to INFO you've stopped all those log entries from being written to
disk. Even more, if your app developers were smart about it, they
checked the IsDebugEnabled property before making the log.Debug() call,
so you're not even evaluating the parms to that call, and sometimes that
can be quite expensive.
So, it's a "known issue" that logging more stuff takes more time, but I
wouldn't call it a bug.
-Walden
--
Walden H Leverich III
Tech Software
(516) 627-3800 x3051
WaldenL@TechSoftInc.com
http://www.TechSoftInc.com
Quiquid latine dictum sit altum viditur.
(Whatever is said in Latin seems profound.)
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Michael Schall
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| 02/25/2009 8:36 PM |
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| What appenders are you using? I assume one of them is the rolling file appender? How large is the log file produced with the setting at DEBUG vs INFO?
If you need to keep the debug information you can look at the BufferingForwardingAppender. The following will buffer 255 messages before writing to the file, unless there is a WARN or higher message, then the buffer is flushed immediately. This should hopefully let the error message that crashes the system still make it to the log file.:)
I don't know how your loggers are setup, but you can turn off at that level as well.
<log4net>
<appender name="BufferingForwardingAppender" type="log4net.Appender.BufferingForwardingAppender" > <bufferSize value="255" />
<lossy value="false" />
<evaluator type="log4net.Core.LevelEvaluator">
<threshold value="WARN"/>
</evaluator>
<appender-ref ref="RollingFile" /> </appender>
<appender name="RollingFile" type="log4net.Appender.RollingFileAppender"> <file value="..\..\log\web.log" />
<appendToFile value="true" /> <maximumFileSize value="100MB" />
<maxSizeRollBackups value="-1" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="%5level [%date] [%thread] %-30.30logger{2} %message%newline" />
</layout>
</appender>
<root>
<level value="DEBUG" />
<appender-ref ref="BufferingForwardingAppender" /> </root>
</log4net> |
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Graham Walsh
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| 02/26/2009 8:22 AM |
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Thanks Walden for the reply, that makes total sense. The error is on our part (we're in production with debug on as its a greenfield project).
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Graham Walsh
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| 02/26/2009 9:09 AM |
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sorry, but I'm having trouble with one part of this config, I always do. I have taken the BufferingForwardingAppender and put it in place, its works a treat.
I've also got another appender which is used to display log output in the GUI window. Now I want BufferingForwardingAppender (which logs to file) to log at debug level but my other appender (RichTextFormAppender) to log at just INFO level. I can't get this working though.
My (messy) log4net stuff looks like this, could anybody let me know how I can get the two levels of logging in place? Once thats done, I'm water tight in terms of delivery
thanks much
Graham
< log4net>
< appender name="BufferingForwardingAppender" type="log4net.Appender.BufferingForwardingAppender" >
< bufferSize value="255" />
< lossy value="false" />
< evaluator type="log4net.Core.LevelEvaluator">
< threshold value="DEBUG"/>
</ evaluator>
< appender-ref ref="RollingFile" />
</ appender>
< appender name="RollingFile" type="log4net.Appender.RollingFileAppender">
< file value="logs/NewLogFile.log" />
< appendToFile value="true" />
< maximumFileSize value="100MB" />
< maxSizeRollBackups value="-1" />
< layout type="log4net.Layout.PatternLayout">
< conversionPattern value="%5level [%date] [%thread] %-30.30logger{2} %message%newline" />
</ layout>
</ appender>
< appender name="MainFormRichTextAppender" type="log4net.Appender.RichTextBoxAppender">
< appendToFile value="true" />
< maximumFileSize value="250000KB" />
< maxSizeRollBackups value="2" />
< layout type="log4net.Layout.PatternLayout">
< conversionPattern value="%date [%-2thread] %-5level %-70logger - %message%newline" />
</ layout>
< code lang="XML" escaped="true">
< mapping>
< level value="DEBUG" />
< textColorName value="DarkGreen" />
< fontFamilyName value="Microsoft Sans Serif"/>
< pointSize value="6.75" />
</ mapping>
< mapping>
< level value="INFO" />
< textColorName value="Black" />
< fontFamilyName value="Microsoft Sans Serif"/>
< pointSize value="6.75" />
</ mapping>
< mapping>
< level value="WARN" />
< textColorName value="Blue" />
< fontFamilyName value="Microsoft Sans Serif"/>
< pointSize value="6.75" />
</ mapping>
< mapping>
< level value="ERROR" />
< textColorName value="Red" />
<!-- <bold value="true" />-->
< fontFamilyName value="Microsoft Sans Serif"/>
< pointSize value="6.75" />
</ mapping>
< mapping>
< level value="FATAL" />
< textColorName value="Black" />
< fontFamilyName value="Microsoft Sans Serif"/>
< pointSize value="6.75" />
</ mapping>
</ code>
</ appender>
< root>
< level value="DEBUG" />
< appender-ref ref="BufferingForwardingAppender" />
< appender-ref ref="MainFormRichTextAppender"/>
</ root>
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Graham Walsh
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| 02/26/2009 9:33 AM |
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Sorry, ignore that last email, its actually working as I want.
Does anybody know if its possible to configure a RichTextBoxAppender (log output goes to a rich text box, its a contribution by another engineer not the original author(s) of log4net, (I think). If I can get buffering in place for the RichTextBox appender, I will have the same output but without the overhead (i.e. DEBUG info at no price.. so to speak).
thanks
Graham
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Walden H. Leverich
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| 02/26/2009 5:27 PM |
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> DEBUG info at no price.. so to speak
Can't help on the buffering, but your comment above isn't necessarily correct at any rate. It depends on where the performance his of the Debug() call is. Sure there's a hit on writing the log to disk, and the buffering helps there, but there is also the hit of generating the text for the debug call in the first place. There's the method call, there's the string concatenation, there's likely numerous .ToString() calls, if you're looking for line#s in the log file then there's the (high) cost of getting that information. None of these issues will be removed by buffering the write to disk. I'm not saying buffing won't buy you something, it will. But it doesn't give you DEBUG at no price.
-Walden
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