Messages with empty marshalledProperties
----------------------------------------
Key: AMQ-3593
URL: https://issues.apache.org/jira/browse/AMQ-3593
Project: ActiveMQ
Issue Type: Bug
Affects Versions: 5.5.1, 5.4.2
Environment: * OS: Linux version 2.6.9-67.0.4.ELlargesmp
([email protected]) (gcc version 3.4.6 20060404 (Red Hat
3.4.6-9)) #1 SMP Fri Jan 18 05:10:01 EST 2008
* JVM (-server option in use): Java(TM) SE Runtime Environment (build
1.6.0_24-b07) Java HotSpot(TM) Server VM (build 19.1-b02, mixed mode)
Reporter: Luca Zenti
Sometimes messages arrive on the client with an empty "marshalledProperties"
field. This causes an exception trying to unmarshall them.
This happens very rarely, but we've got at least 2-3 cases a day per subscriber
in our production environment.
We use a broker embedded with a server component that publishes messages on
topics. The subscribers are remote.
I was unable to replicate the problem on my Windows workstation, nor to
reproduce it precisely.
Attached you can find a simple pair of programs (the publisher and the
subscriber) that can reproduce the issue within 5 minutes at most on my
environment. This happens only if at least one of the subscribers runs on a
remote machine and it seems to happen quickly with more clients connected.
The publishing program has a command line arguments that allows to adjust the
publishing rate, in my case with 10,000 messages per second and 2 clients the
problem happens within a couple of minutes.
I also found a workaround for this problem: as far as I can understand, my
original message is copied as a Java object to the broker (the broker is
embedded, so there is no need to serialize it), then it is copied using its
copy method to one or more new ActiveMQMessage instances and these are pushed
into the consumer queues and then serialized to be sent over tcp.
I think that under some particular conditions the properties are not serialized
into the marshalledProperties field or this happens after the message has been
actually sent.
My workaround is to force the marshalling of properties into the
marshalledProperties field when the message is copied using the copy method.
This is not very clean, but still acceptable. The problem is that, in order for
this to work, I need to create messages of a subclass of ActiveMqBytesMessage
using an explicit constructor call rather that session.createBytesMessage() and
I need to set the connection into them.
Here is the code of my redefined class (this is the BytesMessage version, but
the same is applicable to other kinds of messages):
{noformat}
import java.io.DataOutputStream;
import java.io.IOException;
import javax.jms.Session;
import org.apache.activemq.ActiveMQSession;
import org.apache.activemq.command.ActiveMQBytesMessage;
import org.apache.activemq.command.Message;
import org.apache.activemq.util.ByteArrayOutputStream;
import org.apache.activemq.util.MarshallingSupport;
public class EarlySerializingBytesMessage extends ActiveMQBytesMessage
{
private static final org.apache.log4j.Logger logger =
org.apache.log4j.Logger.getLogger(EarlySerializingBytesMessage.class);
public EarlySerializingBytesMessage(Session session)
{
ActiveMQSession activeMqSession = (ActiveMQSession)session;
setConnection(activeMqSession.getConnection());
}
/*
* We redefine <code>copy</code> to force the marshalling of properties
here and avoid a problem we've found with serialized properties
* arriving empty on the client side.
* This is a workaround to make sure the properties are already serialized
when ActiveMQ actually sends the message to
* the client.
* This happens very rarely and it is very difficult to spot this error in
a "normal" testing session.
* To have reasonable changes to reproduce it, we use a stress test tool
that sends 5000 messages a second and at that rate
* the error happens usually within 10 minutes, so we can say that one
message every million is typically affected.
* The actual problem is probably due to a bug in the ActiveMQ broker.
Basically, it serializes every message just before
* sending it and it happens that the marshalled properties are missing the
resulting message, so we get an error on the client
* as soon as we try to read them.
* Since we use an embedded broker, our original message is never
serialized, it is passed into the publishing queue as a Java object,
* then it is copied into a new message of the same base type
(ActiveMQBytesMessage, in this case) and pushed into the subscribers'
* queues (a topic is actually implemented as a series of queues, one for
each subscriber). In order to do this, the <code>copy</code>
* method is invoked, we redefine it to early serialize the properties and
make sure that this step is not skipped.
*/
@Override
public Message copy()
{
try
{
ByteArrayOutputStream baos = new ByteArrayOutputStream();
DataOutputStream os = new DataOutputStream(baos);
MarshallingSupport.marshalPrimitiveMap(properties, os);
os.close();
marshalledProperties = baos.toByteSequence();
}
catch(IOException exc)
{
logger.error("Error marhalling message properties, message was " +
this, exc);
}
return super.copy();
}
}
{noformat}
The problem happens both on Java and C# clients, with the following stacktraces:
Java:
{noformat}
javax.jms.JMSException: java.io.EOFException
at
org.apache.activemq.util.JMSExceptionSupport.create(JMSExceptionSupport.java:62)
at
org.apache.activemq.filter.PropertyExpression.evaluate(PropertyExpression.java:199)
at
org.apache.activemq.command.ActiveMQMessage.getObjectProperty(ActiveMQMessage.java:509)
at
org.apache.activemq.command.ActiveMQMessage.getStringProperty(ActiveMQMessage.java:604)
at
activemq.emptypropertiestest.Subscriber$1.onMessage(Subscriber.java:65)
at
org.apache.activemq.ActiveMQMessageConsumer.dispatch(ActiveMQMessageConsumer.java:1230)
at
org.apache.activemq.ActiveMQSessionExecutor.dispatch(ActiveMQSessionExecutor.java:134)
at
org.apache.activemq.ActiveMQSessionExecutor.iterate(ActiveMQSessionExecutor.java:205)
at
org.apache.activemq.thread.PooledTaskRunner.runTask(PooledTaskRunner.java:127)
at
org.apache.activemq.thread.PooledTaskRunner$1.run(PooledTaskRunner.java:48)
at
java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.io.EOFException
at java.io.DataInputStream.readInt(DataInputStream.java:375)
at
org.apache.activemq.util.MarshallingSupport.unmarshalPrimitiveMap(MarshallingSupport.java:83)
at
org.apache.activemq.util.MarshallingSupport.unmarshalPrimitiveMap(MarshallingSupport.java:73)
at
org.apache.activemq.command.Message.unmarsallProperties(Message.java:202)
at org.apache.activemq.command.Message.getProperty(Message.java:159)
at
org.apache.activemq.filter.PropertyExpression.evaluate(PropertyExpression.java:197)
... 11 more
{noformat}
C#:
{noformat}
System.IO.EndOfStreamException: Unable to read beyond the end of the stream.
at System.IO.MemoryStream.InternalReadInt32()
at System.IO.BinaryReader.ReadInt32()
at Apache.NMS.Util.EndianBinaryReader.ReadInt32()
at Apache.NMS.Util.PrimitiveMap.UnmarshalPrimitiveMap(BinaryReader dataIn)
at Apache.NMS.Util.PrimitiveMap.UnmarshalPrimitiveMap(Byte[] data)
at Apache.NMS.Util.PrimitiveMap.Unmarshal(Byte[] data)
at Apache.NMS.ActiveMQ.Commands.ActiveMQMessage.get_Properties()
...
{noformat}
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
