Had a question about Mina thread pools.
I posted a snippet of my filter chain building code on a bug report
recently:
protocolAcceptor = new NioSocketAcceptor();
protocolAcceptor.setDefaultLocalAddress(new
InetSocketAddress(protocolPort));
protocolAcceptor.setReuseAddress(true);
DefaultIoFilterChainBuilder filterChainBuilder =
protocolAcceptor.getFilterChain();
filterChainBuilder.addLast("logger", new
LoggingFilter(ProfileCacheServer.class));
readerThreadPool = new OrderedThreadPoolExecutor();
filterChainBuilder.addLast("readExecutor", new
ExecutorFilter(readerThreadPool, IoEventType.MESSAGE_RECEIVED));
filterChainBuilder.addLast("codec", new ProtocolCodecFilter(new
TextLineCodecFactory(ParseConstants.UTF8_CHARSET)));
writerThreadPool = new OrderedThreadPoolExecutor();
filterChainBuilder.addLast("writeExecutor", new
ExecutorFilter(writerThreadPool, IoEventType.WRITE));
protocolAcceptor.setHandler(protocolHandler);
Someone commented back tangentially about what I had written that they
thought the filter chain code I was using was a mistake:
"First of all, adding a (reading) thread pool/executor filter before
codec filter is a really bad idea! ... Try moving the reading executor
behind the codec and remove the writing one."
I didn't understand why this should be the case, and wrote the OP back
asking for clarification, but didn't hear back. Was hoping someone here
might be able to shed some light.
My intention by having 2 thread pools was to have a pool of threads on
both message input and message output processing, thereby avoiding
bottlenecks where handling incoming messages might delay outgoing
messages and vice versa. The idea is that I would read messages using
one thread pool and then feeding them to the codec filter for
processing. Then, similarly, I would have a pool of threads that
handled writing message responses back out to the socket.
So why then would this setup be "a really bad idea"?
TIA,
DR
