Re: [openjms-user] Multiple receivers for one queue.

[William M. <wil...@ma...>]

On 15 Nov, 2004, at 1:26 pm, William Moore wrote:

> Is it possible to have more than one client listening to a persistent  
> queue?

> I tried using rmi instead. That was much slower and did not fare any  
> better in managing more than one client.

I discovered the difficulty with rmi (and part of the difficulty with  
http) was running a firewall on the second computer. I turned the  
firewall off and managed to get two clients started successfully under  
both rmi and http. However, I now have a different problem under http.

I am now only running one client listening to the persistent queue. The  
queue gets one message (from elsewhere) and the client successfully  
receives the message and starts processing it. The processing involves  
submitting a series of new messages back to the queue. During the  
process of submitting these new messages over an http connection, the  
server loses contact with the client. Here is an extract from the  
server log with an http connection:

2004-11-16 11:30:57,505 DEBUG org.exolab.jms.persistence.RDBMSAdapter -  
addMessageHandle,5
2004-11-16 11:30:57,931 DEBUG org.exolab.jms.persistence.RDBMSAdapter -  
addMessage,5
2004-11-16 11:30:57,933 DEBUG org.exolab.jms.persistence.MessageHandles  
- addMessageHandle(handle=[consumer=elease_queue,  
destination=elease_queue-true,  
id=ID:07a41af0-bb70-1004-8e98-64f552359569])
2004-11-16 11:30:57,946 DEBUG org.exolab.jms.persistence.RDBMSAdapter -  
addMessageHandle,12
2004-11-16 11:30:58,303 DEBUG  
org.exolab.jms.server.http.HttpJmsSessionSender - Failed to send  
message to client
java.io.IOException: Server returned HTTP response code: 500 for URL:  
http://172.16.1.3:8080/openjms/OpenJMSClient
	at  
sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnec 
tion.java:575)
	at org.exolab.core.http.HttpClient.sendMessage(HttpClient.java:288)
	at org.exolab.core.http.HttpClient.send(HttpClient.java:141)
	at  
org.exolab.jms.server.http.HttpJmsSessionSender.onMessage(HttpJmsSession 
Sender.java:149)
	at  
org.exolab.jms.server.JmsServerSession.onMessage(JmsServerSession.java: 
942)
	at  
org.exolab.jms.messagemgr.QueueConsumerEndpoint.deliverMessages(QueueCon 
sumerEndpoint.java:177)
	at  
org.exolab.jms.messagemgr.ConsumerEndpoint.run(ConsumerEndpoint.java: 
425)
	at  
org.exolab.core.threadPool.ThreadPoolWorker.runIt(ThreadPoolWorker.java: 
191)
	at  
org.exolab.core.threadPool.ThreadPoolWorker.runWork(ThreadPoolWorker.jav 
a:178)
	at  
org.exolab.core.threadPool.ThreadPoolWorker.access$000(ThreadPoolWorker. 
java:67)
	at  
org.exolab.core.threadPool.ThreadPoolWorker$1.run(ThreadPoolWorker.java: 
122)
	at java.lang.Thread.run(Thread.java:491)
2004-11-16 11:30:58,327 DEBUG org.exolab.jms.server.JmsServerSession -  
close() [sessionId=077a691c-bb70-1004-896d-141fa4dff4fd]
2004-11-16 11:30:58,328 DEBUG org.exolab.jms.messagemgr.ConsumerManager  
- deleteConsumerEndpoint(consumer=[clientId=1,  
destination=elease_queue-true,  
session=[sessionId=077a691c-bb70-1004-896d-141fa4dff4fd]])
2004-11-16 11:30:58,332 DEBUG org.exolab.jms.messagemgr.ConsumerManager  
- removeFromConsumerCache(name=077c7234-bb70-1004-896d-141fa4dff4fd)
2004-11-16 11:30:58,334 ERROR  
org.exolab.jms.messagemgr.QueueConsumerEndpoint -  
org.exolab.jms.server.ClientDisconnectionException: Server returned  
HTTP response code: 500 for URL:  
http://172.16.1.3:8080/openjms/OpenJMSClient
org.exolab.jms.server.ClientDisconnectionException: Server returned  
HTTP response code: 500 for URL:  
http://172.16.1.3:8080/openjms/OpenJMSClient
	at  
org.exolab.jms.server.http.HttpJmsSessionSender.onMessage(HttpJmsSession 
Sender.java:155)
	at  
org.exolab.jms.server.JmsServerSession.onMessage(JmsServerSession.java: 
942)
	at  
org.exolab.jms.messagemgr.QueueConsumerEndpoint.deliverMessages(QueueCon 
sumerEndpoint.java:177)
	at  
org.exolab.jms.messagemgr.ConsumerEndpoint.run(ConsumerEndpoint.java: 
425)
	at  
org.exolab.core.threadPool.ThreadPoolWorker.runIt(ThreadPoolWorker.java: 
191)
	at  
org.exolab.core.threadPool.ThreadPoolWorker.runWork(ThreadPoolWorker.jav 
a:178)
	at  
org.exolab.core.threadPool.ThreadPoolWorker.access$000(ThreadPoolWorker. 
java:67)
	at  
org.exolab.core.threadPool.ThreadPoolWorker$1.run(ThreadPoolWorker.java: 
122)
	at java.lang.Thread.run(Thread.java:491)
2004-11-16 11:30:58,347 DEBUG org.exolab.jms.persistence.RDBMSAdapter -  
addMessage,6
2004-11-16 11:30:58,349 DEBUG org.exolab.jms.persistence.MessageHandles  
- addMessageHandle(handle=[consumer=elease_queue,  
destination=elease_queue-true,  
id=ID:07a4b730-bb70-1004-8e98-64f552359569])

This looks to me  as if the server is attempting to send the first new  
message back to the client before the client has finished processing  
the original message and failing to do so. It then attempts to close  
the client and fails to do that as well. When the client then attempts  
to close itself later, that also fails. Here is the server log from  
that:

2004-11-16 11:33:27,715 DEBUG  
org.exolab.jms.server.mipc.IpcJmsSessionConnection - Failed to locate  
session=077a691c-bb70-1004-896d-141fa4dff4fd

and the clients gets this error from the server:

javax.jms.JMSException: Failed to process request stopMessageDelivery:  
session not found
         <<no stack trace available>>

Everything works as I expect when using an rmi connection.

Do I need to set the http connection up differently so it operates as I  
expect?

Thanks in advance.

William