On my machine I noticed that when sending multiple logging events to a SocketAppender, only the first event gets serialized and sent over the wire to a ServerSocketReceiver.

Debuging the code, I found out that for sending loggingEvents the SocketAppender uses either a SynchronousQueue or an ArrayBlockingQueue in order to make producer-consumer and send serialized events to the socket. That BlockingQueue does behave erratically on my machine.

To demonstrate that I included a small java test that will send 3 events to a SynchronousQueue and to an ArrayBlockingQueue and the output is this:

1. 1. 1. start test SynchronousQueue###
         + appender thread started

• send 3 events
• no more events to be sent
  + received event 1
  + appender thread ended
  1. 1. end test ###
     2. start test ArrayBlockingQueue[2]###
        + appender thread started
• send 3 events
• no more events to be sent
  1. 1. end test ###
     2. start test ArrayBlockingQueue[3]###
        + appender thread started
• send 3 events
• no more events to be sent
  + received event 1
  + received event 2
  + received event 3
  + appender thread ended
  1. 1. end test ###
        This shows that the SynchronousQueue only process the first event and ArrayBlockingQueue[2] does not work at all.

Another test iteration:

1. 1. 1. start test SynchronousQueue###
         + appender thread started

• send 3 events
• no more events to be sent
  + received event 1
  + appender thread ended
  1. 1. end test ###
     2. start test ArrayBlockingQueue[2]###
        + appender thread started
• send 3 events
• no more events to be sent
  + received event 1
  + received event 2
  + appender thread ended
  1. 1. end test ###
     2. start test ArrayBlockingQueue[3]###
        + appender thread started
• send 3 events
• no more events to be sent
  + received event 1
  + received event 2
  + received event 3
  + appender thread ended
  1. 1. end test ###
        This time the SynchronousQueue only processes the first event and the ArrayBlockingQueue[2] processes the first 2 events.

Linux mobile-pc 3.10.17 #2 SMP Wed Oct 23 16:34:38 CDT 2013 x86_64 Intel(R) Core(TM)2 CPU T7200 @ 2.00GHz GenuineIntel GNU/Linux
java version "1.7.0_45"