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(StreamI
oHandler.java:223)

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

at
org.apache.mina.io.handler.StreamIoHandler$PipedInputStream.read(StreamI
oHandler.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.ru
n(PokerTelnetHandler.java:340)

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

at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.ja
va: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

 

[ Post a follow-up to this message ]

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:jalberto-FQMVDHFwfny6lNtOUNzE6A@pub
lic.gmane.org] 
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(StreamI
oHandler.java:223)

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

at
org.apache.mina.io.handler.StreamIoHandler$PipedInputStream.read(StreamI
oHandler.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.ru
n(PokerTelnetHandler.java:340)

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

at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.ja
va: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

 



This e-mail and any attachment is for authorised use by the intended recipie
nt(s) only. It may contain proprietary material, confidential information an
d/or be subject to legal privilege. It should not be copied, disclosed to, r
etained or used by, any other party. If you are not an intended recipient th
en please promptly delete this e-mail and any attachment and all copiesand i
nform the sender. Thank you.

[ Post a follow-up to this message ]

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:dave.irving-iKsOTpgdUR76V6G2DxALlg@public.gma
ne.org] 
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:jalberto-FQMVDHFwfny6lNtOUNzE6A@pub
lic.gmane.org] 
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(StreamI
oHandler.java:223)

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

at
org.apache.mina.io.handler.StreamIoHandler$PipedInputStream.read(StreamI
oHandler.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.ru
n(PokerTelnetHandler.java:340)

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

at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.ja
va: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

 

 

This e-mail and any attachment is for authorised use by the intended
recipient(s) only. It may contain proprietary material, confidential
information and/or be subject to legal privilege. It should not be
copied, disclosed to, retained or used by, any other party. If you are
not an intended recipient then please promptly delete this e-mail and
any attachment and all copies and inform the sender. Thank you.

[ Post a follow-up to this message ]

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
Dave
 
 
 
 

________________________________

From: Jose Alberto Fernandez [mailto:jalberto-FQMVDHFwfny6lNtOUNzE6A@pub
lic.gmane.org] 
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:dave.irving-iKsOTpgdUR76V6G2DxALlg@public.gma
ne.org] 
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:jalberto-FQMVDHFwfny6lNtOUNzE6A@pub
lic.gmane.org] 
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(StreamI
oHandler.java:223)

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

at
org.apache.mina.io.handler.StreamIoHandler$PipedInputStream.read(StreamI
oHandler.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.ru
n(PokerTelnetHandler.java:340)

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

at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.ja
va: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

 

 

This e-mail and any attachment is for authorised use by the intended
recipient(s) only. It may contain proprietary material, confidential
information and/or be subject to legal privilege. It should not be
copied, disclosed to, retained or used by, any other party. If you are
not an intended recipient then please promptly delete this e-mail and
any attachment and all copies and inform the sender. Thank you.

[ Post a follow-up to this message ]

Thanks Dave, now I understand the issue.

Will see if you guys come with a smart solution before mocking with the
thread parameters since we use several protocols and they all share the
same threadfilter in the IoAcceptor.

 

Jose Alberto

 

________________________________

From: Irving, Dave [mailto:dave.irving-iKsOTpgdUR76V6G2DxALlg@public.gma
ne.org] 
Sent: 24 November 2005 16:05
To: Apache Directory Developers List
Subject: RE: [MINA] Error on StreamIOHandler

 

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

Dave

 

 

 

 

 

________________________________

From: Jose Alberto Fernandez [mailto:jalberto-FQMVDHFwfny6lNtOUNzE6A@pub
lic.gmane.org] 
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:dave.irving-iKsOTpgdUR76V6G2DxALlg@public.gma
ne.org] 
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:jalberto-FQMVDHFwfny6lNtOUNzE6A@pub
lic.gmane.org] 
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(StreamI
oHandler.java:223)

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

at
org.apache.mina.io.handler.StreamIoHandler$PipedInputStream.read(StreamI
oHandler.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.ru
n(PokerTelnetHandler.java:340)

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

at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.ja
va: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

 

 

This e-mail and any attachment is for authorised use by the intended
recipient(s) only. It may contain proprietary material, confidential
information and/or be subject to legal privilege. It should not be
copied, disclosed to, retained or used by, any other party. If you are
not an intended recipient then please promptly delete this e-mail and
any attachment and all copies and inform the sender. Thank you.

[ Post a follow-up to this message ]

I can confirm that I've now reproduced this problem. Changing the
ThreadPoolFilter keep-alive time changes the amount of time required
before the exception is obvserved - so I think we got to the root cause
(PipedInputStream doesn't like producer threads dying).
 
Possible solutions which spring to mind:
 
1) Mina could use its own "MinaPipedInput/OutputStream" or something.
2) A ThreadPoolFilter Worker thread could somehow know that it was
logically still required even though it hadn't been active for a while
(maybe a session attribute?). StreamIoHandler would then set this
attribute on a write or something like that (and remove it onIdle /
close whatever). This is quite a bit more hacky than (1).
 
Dave

________________________________

From: Jose Alberto Fernandez [mailto:jalberto-FQMVDHFwfny6lNtOUNzE6A@pub
lic.gmane.org] 
Sent: 24 November 2005 16:53
To: Apache Directory Developers List
Subject: RE: [MINA] Error on StreamIOHandler



Thanks Dave, now I understand the issue.

Will see if you guys come with a smart solution before mocking with the
thread parameters since we use several protocols and they all share the
same threadfilter in the IoAcceptor.

 

Jose Alberto

 

________________________________

From: Irving, Dave [mailto:dave.irving-iKsOTpgdUR76V6G2DxALlg@public.gma
ne.org] 
Sent: 24 November 2005 16:05
To: Apache Directory Developers List
Subject: RE: [MINA] Error on StreamIOHandler

 

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

Dave

 

 

 

 

 

________________________________

From: Jose Alberto Fernandez [mailto:jalberto-FQMVDHFwfny6lNtOUNzE6A@pub
lic.gmane.org] 
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:dave.irving-iKsOTpgdUR76V6G2DxALlg@public.gma
ne.org] 
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:jalberto-FQMVDHFwfny6lNtOUNzE6A@pub
lic.gmane.org] 
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(StreamI
oHandler.java:223)

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

at
org.apache.mina.io.handler.StreamIoHandler$PipedInputStream.read(StreamI
oHandler.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.ru
n(PokerTelnetHandler.java:340)

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

at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.ja
va: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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[ Post a follow-up to this message ]

DIRMINA-129 created to cover this issue.

________________________________

From: Irving, Dave [mailto:dave.irving-iKsOTpgdUR76V6G2DxALlg@public.gma
ne.org] 
Sent: 24 November 2005 17:55
To: Apache Directory Developers List
Subject: RE: [MINA] Error on StreamIOHandler


I can confirm that I've now reproduced this problem. Changing the
ThreadPoolFilter keep-alive time changes the amount of time required
before the exception is obvserved - so I think we got to the root cause
(PipedInputStream doesn't like producer threads dying).
 
Possible solutions which spring to mind:
 
1) Mina could use its own "MinaPipedInput/OutputStream" or something.
2) A ThreadPoolFilter Worker thread could somehow know that it was
logically still required even though it hadn't been active for a while
(maybe a session attribute?). StreamIoHandler would then set this
attribute on a write or something like that (and remove it onIdle /
close whatever). This is quite a bit more hacky than (1).
 
Dave

________________________________

From: Jose Alberto Fernandez [mailto:jalberto-FQMVDHFwfny6lNtOUNzE6A@pub
lic.gmane.org] 
Sent: 24 November 2005 16:53
To: Apache Directory Developers List
Subject: RE: [MINA] Error on StreamIOHandler



Thanks Dave, now I understand the issue.

Will see if you guys come with a smart solution before mocking with the
thread parameters since we use several protocols and they all share the
same threadfilter in the IoAcceptor.

 

Jose Alberto

 

________________________________

From: Irving, Dave [mailto:dave.irving-iKsOTpgdUR76V6G2DxALlg@public.gma
ne.org] 
Sent: 24 November 2005 16:05
To: Apache Directory Developers List
Subject: RE: [MINA] Error on StreamIOHandler

 

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

Dave

 

 

 

 

 

________________________________

From: Jose Alberto Fernandez [mailto:jalberto-FQMVDHFwfny6lNtOUNzE6A@pub
lic.gmane.org] 
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:dave.irving-iKsOTpgdUR76V6G2DxALlg@public.gma
ne.org] 
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:jalberto-FQMVDHFwfny6lNtOUNzE6A@pub
lic.gmane.org] 
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(StreamI
oHandler.java:223)

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

at
org.apache.mina.io.handler.StreamIoHandler$PipedInputStream.read(StreamI
oHandler.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.ru
n(PokerTelnetHandler.java:340)

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

at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.ja
va: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

 

 

This e-mail and any attachment is for authorised use by the intended
recipient(s) only. It may contain proprietary material, confidential
information and/or be subject to legal privilege. It should not be
copied, disclosed to, retained or used by, any other party. If you are
not an intended recipient then please promptly delete this e-mail and
any attachment and all copies and inform the sender. Thank you.

[ Post a follow-up to this message ]

On a related note, I'm naively considering a move to a semi-synchronous
architecture for my project and have been wondering whether MINA and
specifically StreamIOHandler are a good fit.

Specifically, I have a lot of code that expects to use InputStreams, but
parts of my code also spend a lot of time waiting for external systems
to do their business, during which time I'd prefer not to have useful
threads blocked waiting for them.

I was thinking I could extend StreamIOHandler with a "streaming" flag.
If the streaming flag were set, likely because someone had asked for an
InputStream and not closed it yet, I would fire any received data into
the Piped*Stream pairs, and if not, I would take a more event-driven
approach to handling the block.

Does this sound reasonable?

Thanks,

-0xe1a

[ Post a follow-up to this message ]

Hi Alex,

2005/11/26, Alex Cruise <alex-a0FWtchhtz9DPfheJLI6IQ@public.gmane.org>:
>
> On a related note, I'm naively considering a move to a semi-synchronous
> architecture for my project and have been wondering whether MINA and
> specifically StreamIOHandler are a good fit.
>
> Specifically, I have a lot of code that expects to use InputStreams, but
> parts of my code also spend a lot of time waiting for external systems
> to do their business, during which time I'd prefer not to have useful
> threads blocked waiting for them.
>
> I was thinking I could extend StreamIOHandler with a "streaming" flag.
> If the streaming flag were set, likely because someone had asked for an
> InputStream and not closed it yet, I would fire any received data into
> the Piped*Stream pairs, and if not, I would take a more event-driven
> approach to handling the block.
>
> Does this sound reasonable?


Are you saying that it would be great if you can switch the mode
(semi-synchronous stream I/O and original MINA way)?  If so, this is a
wonderful idea.

Thanks,
Trustin
--
what we call human nature is actually human habit
--
http://gleamynode.net/

[ Post a follow-up to this message ]

Trustin Lee wrote:

> Are you saying that it would be great if you can switch the mode
> (semi-synchronous stream I/O and original MINA way)?  If so, this is a
> wonderful idea.

That is exactly what I'd *like* to do, but I lack sufficient depth in
asynchronous architecture to know whether it's feasible.  I was hoping
for some opinions. 

BTW, it's conventional wisdom that apart from handling keepalives
efficiently, asynchronous I/O isn't strongly beneficial for Java servlet
systems, since each thread is either 100% busy doing "servlet business"
or 100% idle in the pool.

However, I think there are several "waity" areas that would benefit from
async.  You shouldn't have to block a thread waiting for a slow backend
in a proxy-like system, or when you're waiting for an authentication
response from a heavily loaded LDAP server.  It probably makes sense for
slow clients.  It might even make sense to implement semi-sync database
drivers someday! 

In the long run, I'd like to employ a heuristic approach that would
switch, based on observed latency, back and forth between blocking and
non-blocking I/O on each connection (e.g. go async when latency is >
100ms?).   I like how MINA's modular architecture makes it fairly easy
to experiment with different approaches.  I hope it won't add too much
latency. 

-0xe1a

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