MINA acceptors open a lot of pipes

[Jeff Mesnil]

Hi,

I'm using MINA trunk in an application and I've encountered an issue 
with it in our test suite.

Basically, for each test, our test suite starts & stops a MINA server.
Then depending on the tests, it opens connections or not.

However, even when our tests do not open connection (i.e. only MINA
acceptor is created), an excessive(?) number of pipes is created by MINA 
leading to a "too many open files" exception after a certain number of 
tests.

All the first tests run by our test suite does not use MINA connectors.
I commented out the code to start & stop MINA acceptor to see if it was 
the cause of the number of pipes and it seems it is.

* without MINA start & stop:

$ lsof -p $PID | grep pipe | wc -l
3

* with MINA start & stop:

$ lsof -p $PID | grep pipe | wc -l
203
...
987 -> generate an exception "too many open files"


First question: is it normal that a succession of MINA acceptors 
creation/disposal generates such a number of pipe?

The code I use to start & stop MINA is:

   private void startMINAServer() throws Exception
   {
      if (acceptor == null)
      {
         acceptor = new NioSocketAcceptor();

         // Prepare the configuration
         acceptor.getFilterChain().addLast("mdc", new 
MdcInjectionFilter());
         acceptor.getFilterChain().addLast("codec",
               new ProtocolCodecFilter(new PacketCodecFactory()));
         acceptor.getFilterChain().addLast("logger", new LoggingFilter());

         // Bind
         acceptor.setLocalAddress(new InetSocketAddress(PORT));
         acceptor.setReuseAddress(true);
         acceptor.getSessionConfig().setReuseAddress(true);
         acceptor.getSessionConfig().setKeepAlive(true);
         acceptor.setDisconnectOnUnbind(false);

         acceptor.setHandler(new ServerHandler());
         acceptor.bind();

         info("Started MINA on port " + PORT);
      }
   }

   private void stopMINAServer()
   {
      if (acceptor != null)
      {
         acceptor.unbind();
         acceptor.dispose();

         info("Stopped MINA ");
      }
   }

I thought at first that I was responsible of the increase of pipes by 
having unclosed streams. I don't think it is the case: I only used 
ByteArray streams in the codecs.

It also seems that for each start of MINA, the increase is by 8 open 
pipes every time and it does not decrease every time the acceptor is 
disposed.

I'm still investigating and trying to isolate this problem but I was 
wondering if it rings anyone's bell.
Do you have any idea of the cause of all these open pipes?

Thanks for the help,
jeff