Performance of PatternLayout

[Martin Kozubek]

Hello,

I have noticed performance hit after adding a custom property and using 
a PatternConverter to render it. It's the same for any context 
property(global,thread,event).  If there is a %property{smthing} in 
PatternConverter's string, the logging process results into call of 
Principal.WindowsIdentity.GetCurrent().Name.

The code containing this call is in the LoggingEvent class. It is getter 
of property UserName. Since log4net v 1.2.12 the 
LoggingEvent.CreateCompositeProperties() is getting this property.  The 
problem is that this method is called once for logging event whenever 
there is some %property{} to be rendered.

This results in that even if I don't use the username, but I add and use 
some custom property in the event, the logging process is ~10 times slower.

I can solve it by programming my own layout instead of PatternLayout, 
but I am wondering if is it an expected behavior. Should that be 
reported to developers?

MK