|
RSS Feed - WebSphere MQ Support
|
RSS Feed - Message Broker Support
|
 |
|
Zero-Byte (empty) messages generated |
« View previous topic :: View next topic » |
Author |
Message
|
GarvAlbert |
Posted: Wed Jun 20, 2007 6:53 am Post subject: Zero-Byte (empty) messages generated |
|
|
Newbie
Joined: 20 Jun 2007 Posts: 2 Location: Washington DC
|
Hi, all
First time posting ...
We're having a strange problem where zero-byte messages are being pulled from a queue.
Due to a limitation of the COTS product we're using, and to integrate our MQ message processing with existing architecture, we're processing messages as follows, every 5 minutes:
1) PEEK the queue, n documents at a time (queuedepth = n < 1k).
Atomically:
A) Persist each message payload as an archive file on the filesystem
B) Process the data from this archive file
C) Log successful docs, empty docs, and invalid docs
2) GET n documents from Q (flushing processed docs)
A) issue MQGet
B) "Swallow" data.
This is perhaps not the cleanest way to do things, but our central issue is that we receive every once in a while (and consecutively) a batch of 3-5 zero-byte messages. Our handling is to log these and essentially ignore them. When doing parity/sanity checks with the data provider, the number and checksum on all the "good" messages matches everything they actually sent -- so in essence these "empty" messages are false positives.
Is there some intricacy involved in peeking/browsing that could cause this? Is this known behavior when there are network issues? Has anybody else witnessed this? |
|
Back to top |
|
 |
jefflowrey |
Posted: Wed Jun 20, 2007 7:09 am Post subject: |
|
|
Grand Poobah
Joined: 16 Oct 2002 Posts: 19981
|
I guess the first thing I'd try to do is capture some of these empty messages "in the wild", and use something like amqsbcgc to browse the queue and print the messages.
Then I'd know if they were empty on the queue, or just empty after the program read them. _________________ I am *not* the model of the modern major general. |
|
Back to top |
|
 |
GarvAlbert |
Posted: Wed Jun 20, 2007 7:14 am Post subject: Good idea |
|
|
Newbie
Joined: 20 Jun 2007 Posts: 2 Location: Washington DC
|
Good idea.
The problem is that this manifests, on average, once a day, randomly.
We may be able to diagnose this using this method in our staging environment once we go into production (this is not a showstopper -- all valid data is still being received) .
But you're not aware of any browse peculiarities when a message is "inflight"? |
|
Back to top |
|
 |
jefflowrey |
Posted: Wed Jun 20, 2007 7:16 am Post subject: |
|
|
Grand Poobah
Joined: 16 Oct 2002 Posts: 19981
|
A browse is only different from an get in that it doesn't call the code to remove the message from the queue.
The buffer it returns should never be any different. _________________ I am *not* the model of the modern major general. |
|
Back to top |
|
 |
fjb_saper |
Posted: Wed Jun 20, 2007 3:01 pm Post subject: |
|
|
 Grand High Poobah
Joined: 18 Nov 2003 Posts: 20756 Location: LI,NY
|
Are you sure the message is actually empty?
Could it be that the message has no payload but only headers? Like the JMS header and carries a number of attributes in the user folder?
Enjoy  _________________ MQ & Broker admin |
|
Back to top |
|
 |
|
|
 |
|
Page 1 of 1 |
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
|
|
|
|