log4net RollingFileAppender unexpected filename when file already open - log4net

Question

My log4net configuration is:
<log4net>
<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="C:\LogFiles\Staging_WebAQPro\s_waq_" />
<datePattern value="yyyy-MM-dd'.log'" />
<staticLogFileName value="false" />
<preserveLogFileNameExtension value="true" />
<appendToFile value="true" />
<countDirection value="1" />
<rollingStyle value="Composite" />
<maxSizeRollBackups value="-1" />
<maximumFileSize value="10MB" />
<layout type="log4net.Layout.PatternLayout">
<conversionPattern value="[%d]: %15property{adrs}: %4t: %5p: %m%n" />
</layout>
</appender>
<root>
<level value="DEBUG" />
<appender-ref ref="RollingLogFileAppender" />
</root>
</log4net>
And when the IIS w3wp process starts, I get the expected filename of:
s_waq_2015-07-13.0.log
However, when IIS recycles the process, I get the filename (which is a bit a mouthful):
s_waq_2015-07-13.02015-07-13.log.0.log
This is occurring because IIS keeps the old process around, whilst the new process is starting. The new process can't open the expected filename because it is still in use. I don't want to use minimal locking because it is much slower (and this issue only occurs once per day).
Any ideas about how to get a more reasonable filename in this situation?
Many thanks
Ronny

Answer 1

A solution can by to include the processid in your logfile name:
<file type="log4net.Util.PatternString" value="C:\LogFiles\Staging_WebAQPro\s_waq_%processid_" />
This will fix your double date in the filename.