FYI, here is the enhancements that I suggested back in Jan, 2011 that I was 
referring to in my last email.

I have been using the AdoNetAppender for a while now and have a few issues with 
it.


1) If the database that it logs to goes offline it will stop logging messages 
until the application is restarted 

  · You can overcome that issue by setting ReconnectOnError but the problem 
with that is that if the database is still offline it will block your program 
thread until it times out every time it tries to flush the events.


2) Since the AdoNetAppender derives from BufferAppenderSkeleton it buffers 
events before writing to the DB. Not a bad idea unless you want to monitor the 
DB for exceptions in real-time. So let’s say I set the default buffer size to 
20 events. If I am monitoring the DB I won’t see any of the exceptions till it 
hits the buffer size of 20 events.

  · The fix for me is to set the buffer to 1 event so that I get real-time 
results when an exception happens. However I am not taking advantage of 
buffering the events so that the application thread returns quicker and writes 
to the DB less frequent.

Here is the behavior I want.


1) Set by default buffer size to 100

2) Set a buffer flush interval to 60 seconds

3) Set retry logic for DB connection in the event that the DB is unavailable 
and cache the log events being written




So here is an example of how it would work.




Write an exception to AdoNetAppender

Event is buffered

If buffer exceeds 100 events or 60 seconds has elapsed the buffer will be 
flushed

If the appender is unable to talk to the DB it marks the connection as failed 
and caches the events locally

Next write attempts looks to see if the retry time has been exceeded and if so 
attempts to write buffer to DB

Also any local events previously cached from a failure will be written as well.




So now I am back to using a buffer

I now see any exceptions at most 60 seconds after they happen

If the DB goes down I now have retry logic for attempting to write the events 
(key is not every attempt so the application is not being blocked on every 
write) 




Now not being entirely familiar with the source for Log4Net I attempted to add 
these features and have it working. However not sure if my approach is the 
approach you would take for including in your source. 




If anyone likes the features listed above I would be happy to provide the 
source changes. I did this by creating a AdoNetAppenderEx class that looks just 
like the AdoNetAppender but with my additions. 




However I personally think the concept of flushing events on an interval should 
be coded up higher in the BufferAppenderSkeleton as the issue I don’t like is 
having to wait till the number of buffered events is exceeded. Would be nice to 
specify another threshold for buffered events to be time based.




The retry logic however for the DB is essential but don’t want it happening on 
every write but rather a retry after X seconds has elapsed since the last 
failed connection.



Reply via email to