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Emmanuel Lecharny updated DIRMINA-682: -------------------------------------- Summary: We need a better documentation for the ExecutorFilter [was :Writing more than one message will block until the MessageReceived as been fully proceced] (was: Writing more than one message will block until the MessageReceived as been fully proceced) > 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-RC1 > > > 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] -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.