RE: [MINA] Error on StreamIOHandler

Irving, Dave Thu, 24 Nov 2005 08:21:44 -0800

Expanding a bit on this:

ThreadPoolFilter has a default keep alive time of one minute.

If no work comes in to the filter in this time (e.g because you haven't typed anything for a while), a worker thread could shut down.

So, in your example, the following could happen:

1) You write some data over telnet

2) A processor thread writes the data to the StreamIoHandlers PipedOutputStream

3) Your PipedInputStream reads the data. At this point, the processor thread is marked as the last writer (PipedInputStrea#writeSide).

4) You dont send any data for a while (so you are currently blocked in final String command = in.readLine(); in your code).

5) The processor thread idles out (default keep-alive time is one minute)

6) The PipedInputStream detects that the last writer thread is no longer alive and throws a "Pipe Broken" IOException

7) Your code writes this back to the client (in your catch block)

8) Your code closes the connection (your finally block)

I think thats probably whats happening.

To test my theory, try increasing the idle time out of the ThreadPoolFilter - you shouldn't get the exception until this time has elapsed (or decrease it, and observe the failure quicker).

So maybe we need to either use a custom piped stream in StreamIOHandler , or be careful with processor thread keep alives when using VM pipe?

Dave

From: Jose Alberto Fernandez [mailto:[EMAIL PROTECTED]
Sent: 24 November 2005 15:51
To: Apache Directory Developers List
Subject: RE: [MINA] Error on StreamIOHandler

Thanks, not sure if this is my case. As a matter of fact, the stack trace that I printed comes as part of the Telnet output just before the connection is closed.

This are some abstracts of the code loop of my worker thread:

protected void processStreamIo(IoSession i_ioSession, InputStream i_inputStream, OutputStream i_outputStream) {

try {

EXECUTOR_SERVICE.execute(new Worker(i_inputStream, i_outputStream));

} catch (IOException e) {

e.printStackTrace();

i_ioSession.close();

}

public Worker(final InputStream i_in, final OutputStream i_out) throws IOException {

in = new BufferedReader(new InputStreamReader( i_in ) );

out = new PrintWriter(new BufferedWriter( new OutputStreamWriter( i_out ) ), true);

}

public void run() {

try {

while (true) {

final String command = in.readLine();

if (processCommand(command.trim())) {

break;

}

} catch (IOException e) {

e.printStackTrace(out);

} finally {

out.close();

}

As you can see the stack trace is send to the telnet client before closing the connection.

From: Irving, Dave [mailto:[EMAIL PROTECTED]
Sent: 24 November 2005 15:26
To: Apache Directory Developers List
Subject: RE: [MINA] Error on StreamIOHandler

This is just a guess off the top of my head (so apologies if its wildly inaccurate), but I wonder whether it has anything to do with processor threads being shut down if they dont do any work?

When an attempt is made to read from a PipedInputStream, a check is made every second to see whether the last thread to write to the associated PipedOutputStream is still alive.

From PipedInputStream:

int trials = 2;
while (in < 0) {
     if (closedByWriter) {
  /* closed by writer, return EOF */
  return -1;
     }
     if ((writeSide != null) && (!writeSide.isAlive()) && (--trials < 0)) {
  throw new IOException("Pipe broken");
     }
            /* might be a writer waiting */
     notifyAll();
     try {
         wait(1000);
     } catch (InterruptedException ex) {
  throw new java.io.InterruptedIOException();
     }
  }

So, if mina shuts down the thread which caused the last write after inactivity (which I think it might do), this could be the cause.

Dave

From: Jose Alberto Fernandez [mailto:[EMAIL PROTECTED]
Sent: 24 November 2005 15:11
To: Apache Directory Developers List
Subject: [MINA] Error on StreamIOHandler

Hi, we are getting the following stack trace when one is not constantly typing on a telnet session connected using StreamIOHandler:

java.io.IOException: Pipe broken

at java.io.PipedInputStream.read(PipedInputStream.java:255)

at org.apache.mina.io.handler.StreamIoHandler$PipedInputStream.read(StreamIoHandler.java:223)

at java.io.PipedInputStream.read(PipedInputStream.java:305)

at org.apache.mina.io.handler.StreamIoHandler$PipedInputStream.read(StreamIoHandler.java:229)

at sun.nio.cs.StreamDecoder$CharsetSD.readBytes(StreamDecoder.java:411)

at sun.nio.cs.StreamDecoder$CharsetSD.implRead(StreamDecoder.java:453)

at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:183)

at java.io.InputStreamReader.read(InputStreamReader.java:167)

at java.io.BufferedReader.fill(BufferedReader.java:136)

at java.io.BufferedReader.readLine(BufferedReader.java:299)

at java.io.BufferedReader.readLine(BufferedReader.java:362)

at com.cellectivity.poker.clienthandler.telnet.PokerTelnetHandler$Worker.run(PokerTelnetHandler.java:340)

at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:650)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:675)

at java.lang.Thread.run(Thread.java:595)

This is MINA 0.8.1. We have only one connection and this occurs every time we do not use the telnet session for a little while,

less than a minute. Has anyone seen this error before? Any way to solve it?

Jose Alberto

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RE: [MINA] Error on StreamIOHandler

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