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https://issues.apache.org/jira/browse/DIRMINA-682?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12829179#action_12829179
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Victor N commented on DIRMINA-682:
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I agree, it would be great to document ExecutorFilter and especially
OrderedThreadPool in more details!
In the test (2) - what was your filter chain? Did not you use the same
OrderedThreadPoolExecutor for both MESSAGE_RECEIVED and WRITE operations? If I
understand correctly, this could bring to a deadlock because we were already
running MESSAGE_RECEIVED and tried to do WRITE.
> We need a better documentation for the ExecutorFilter [was :Writing more than
> one message will block until the MessageReceived as been fully proceced]
> ------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: DIRMINA-682
> URL: https://issues.apache.org/jira/browse/DIRMINA-682
> Project: MINA
> Issue Type: Improvement
> Affects Versions: 2.0.0-M4
> Reporter: Emmanuel Lecharny
> Priority: Critical
> Fix For: 2.0.0-RC2
>
>
> When a message generates mor ethan one response, then the written responses
> will be sent to the client only when the initial message has been totally
> processed.
> Suppose that we receive one message M, it will be handled by a IoProcessor in
> the process() method, go through the chain to the IoHandler.MessageReceive()
> method. Now, if one want to write more than one response (session.write( R
> )), then those responses will be enqueued until we are back to the process()
> method.
> The issue is due to the fact that the write is done using the IoProcessor
> associated to the current session, leading to a problem : we can't ask the
> IoProcessor instance to unqueue the written message until it is done with the
> current processing( it's running in one single thread).
> The consequences are painfull :
> - if one tries to write two responses, waiting for the first responses to be
> written, this will end with a DeadLock, as we are waiting on the processor we
> are holding
> - if we don't care about waiting for the write to be done, then all the
> responses will be enqueued and stored in memory, until the IoProcessor exit
> from the read processing and start processing the writes, leading to OOM
> Exception
> One solution would be to have to sets of IoProcessors, one for the read, and
> one for the writes. Or to pick a random Processor to process the writes, as
> soon as the processor is not the same as the one processing the reads.
> Here is a sample exhibiting the problem. Just launch it, and use 'telnet
> localhost 8080' in a console, type something, it should write twice the typed
> message, but it just generates an exception - see further - and write back
> the message once. Removing the wait will work, but the messages will be sent
> only when the read has been processed in the
> AbstractPollingIoProcessor.process(T session) method :
> /**
> * Deal with session ready for the read or write operations, or both.
> */
> private void process(T session) {
> // Process Reads
> if (isReadable(session) && !session.isReadSuspended()) {
> read(session);
> }
> // Process writes
> if (isWritable(session) && !session.isWriteSuspended()) {
> scheduleFlush(session);
> }
> }
> The sample code :
> package org.apache.mina.real.life;
> import java.net.InetSocketAddress;
> import org.apache.mina.core.buffer.IoBuffer;
> import org.apache.mina.core.future.WriteFuture;
> import org.apache.mina.core.service.IoHandlerAdapter;
> import org.apache.mina.core.session.IoSession;
> import org.apache.mina.filter.logging.LoggingFilter;
> import org.apache.mina.transport.socket.SocketAcceptor;
> import org.apache.mina.transport.socket.nio.NioSocketAcceptor;
> /**
> * (<b>Entry point</b>) Echo server
> *
> * @author The Apache MINA Project (dev@mina.apache.org)
> */
> public class Main {
> private static class EchoProtocolHandler extends IoHandlerAdapter {
> public void messageReceived(IoSession session, Object message)
> throws Exception {
> System.out.println(new String(((IoBuffer)message).array()));
> // Write the received data back to remote peer
> WriteFuture wf = session.write(((IoBuffer) message).duplicate());
>
> // Here, we will get a Deadlock detection
> wf.awaitUninterruptibly();
>
> // Do a second write
> session.write(((IoBuffer) message).duplicate());
> }
> }
> /** Choose your favorite port number. */
> private static final int PORT = 8080;
> public static void main(String[] args) throws Exception {
> SocketAcceptor acceptor = new NioSocketAcceptor();
>
> // Add a logging filter
> acceptor.getFilterChain().addLast( "Logger", new LoggingFilter() );
>
> // Bind
> acceptor.setHandler(new EchoProtocolHandler());
> acceptor.bind(new InetSocketAddress(PORT));
> System.out.println("Listening on port " + PORT);
> }
> }
> The exception :
> Listening on port 8080
> [20:08:17] INFO [org.apache.mina.filter.logging.LoggingFilter] - CREATED
> [20:08:17] INFO [org.apache.mina.filter.logging.LoggingFilter] - OPENED
> [20:08:19] INFO [org.apache.mina.filter.logging.LoggingFilter] - RECEIVED:
> HeapBuffer[pos=0 lim=6 cap=2048: 74 65 73 74 0D 0A]
> test
> [20:08:30] WARN [org.apache.mina.filter.logging.LoggingFilter] - EXCEPTION :
> java.lang.IllegalStateException: DEAD LOCK: IoFuture.await() was invoked from
> an I/O processor thread. Please use IoFutureListener or configure a proper
> thread model alternatively.
> at
> org.apache.mina.core.future.DefaultIoFuture.checkDeadLock(DefaultIoFuture.java:235)
> at
> org.apache.mina.core.future.DefaultIoFuture.await0(DefaultIoFuture.java:203)
> at
> org.apache.mina.core.future.DefaultIoFuture.awaitUninterruptibly(DefaultIoFuture.java:131)
> at
> org.apache.mina.core.future.DefaultWriteFuture.awaitUninterruptibly(DefaultWriteFuture.java:114)
> at
> org.apache.mina.real.life.Main$EchoProtocolHandler.messageReceived(Main.java:45)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain$TailFilter.messageReceived(DefaultIoFilterChain.java:722)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:434)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain.access$1200(DefaultIoFilterChain.java:48)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain$EntryImpl$1.messageReceived(DefaultIoFilterChain.java:802)
> at
> org.apache.mina.filter.logging.LoggingFilter.messageReceived(LoggingFilter.java:178)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:434)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain.access$1200(DefaultIoFilterChain.java:48)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain$EntryImpl$1.messageReceived(DefaultIoFilterChain.java:802)
> at
> org.apache.mina.core.filterchain.IoFilterAdapter.messageReceived(IoFilterAdapter.java:120)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:434)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain.fireMessageReceived(DefaultIoFilterChain.java:426)
> at
> org.apache.mina.core.polling.AbstractPollingIoProcessor.read(AbstractPollingIoProcessor.java:604)
> at
> org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:564)
> at
> org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:553)
> at
> org.apache.mina.core.polling.AbstractPollingIoProcessor.access$400(AbstractPollingIoProcessor.java:57)
> at
> org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.run(AbstractPollingIoProcessor.java:892)
> at
> org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:65)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
> at java.lang.Thread.run(Thread.java:619)
> [20:08:30] WARN [org.apache.mina.real.life.Main$EchoProtocolHandler] -
> EXCEPTION, please implement
> org.apache.mina.real.life.Main$EchoProtocolHandler.exceptionCaught() for
> proper handling:
> java.lang.IllegalStateException: DEAD LOCK: IoFuture.await() was invoked from
> an I/O processor thread. Please use IoFutureListener or configure a proper
> thread model alternatively.
> at
> org.apache.mina.core.future.DefaultIoFuture.checkDeadLock(DefaultIoFuture.java:235)
> at
> org.apache.mina.core.future.DefaultIoFuture.await0(DefaultIoFuture.java:203)
> at
> org.apache.mina.core.future.DefaultIoFuture.awaitUninterruptibly(DefaultIoFuture.java:131)
> at
> org.apache.mina.core.future.DefaultWriteFuture.awaitUninterruptibly(DefaultWriteFuture.java:114)
> at
> org.apache.mina.real.life.Main$EchoProtocolHandler.messageReceived(Main.java:45)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain$TailFilter.messageReceived(DefaultIoFilterChain.java:722)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:434)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain.access$1200(DefaultIoFilterChain.java:48)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain$EntryImpl$1.messageReceived(DefaultIoFilterChain.java:802)
> at
> org.apache.mina.filter.logging.LoggingFilter.messageReceived(LoggingFilter.java:178)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:434)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain.access$1200(DefaultIoFilterChain.java:48)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain$EntryImpl$1.messageReceived(DefaultIoFilterChain.java:802)
> at
> org.apache.mina.core.filterchain.IoFilterAdapter.messageReceived(IoFilterAdapter.java:120)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain.callNextMessageReceived(DefaultIoFilterChain.java:434)
> at
> org.apache.mina.core.filterchain.DefaultIoFilterChain.fireMessageReceived(DefaultIoFilterChain.java:426)
> at
> org.apache.mina.core.polling.AbstractPollingIoProcessor.read(AbstractPollingIoProcessor.java:604)
> at
> org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:564)
> at
> org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPollingIoProcessor.java:553)
> at
> org.apache.mina.core.polling.AbstractPollingIoProcessor.access$400(AbstractPollingIoProcessor.java:57)
> at
> org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.run(AbstractPollingIoProcessor.java:892)
> at
> org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java:65)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
> at java.lang.Thread.run(Thread.java:619)
> [20:08:30] INFO [org.apache.mina.filter.logging.LoggingFilter] - SENT:
> HeapBuffer[pos=0 lim=6 cap=2048: 74 65 73 74 0D 0A]
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