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From Timothy Bish <tabish...@gmail.com>
Subject Re: Message bandwidth/overheads - how to reduce?
Date Fri, 05 Aug 2011 14:09:16 GMT
On Fri, 2011-08-05 at 07:02 -0700, Phil White wrote:
> Thanks Tim
> 
> I don't think these additional messages are connection/subscribe related
> though; I'm pushing 100 messages out of the publisher, one every second, and
> see the same sequence between each message. Also the 243 packets come
> immediately after the message, whereas I would have expected keep-alives to
> been seen in the absence of message traffic, rather than being triggered by
> it. Here's a typical packet sequence pulled out of Wireshark:
> 

You can set transport.useLogging=true on the Uri to have the client dump
out exactly what messages are coming and going.  That would give a hint
as to the difference between tight and loose encoding.

> --> The message itself
> 23685	99.657686	192.168.1.74	192.168.1.76	TCP	580	61616 > eisport [PSH, ACK]
> Seq=51034 Ack=18744 Win=16987 Len=526	23685
> 
> --> First set of following small packets
> 23686	99.658418	192.168.1.76	192.168.1.74	TCP	58	eisport > 61616 [PSH, ACK]
> Seq=18744 Ack=51560 Win=64483 Len=4	23686
> 23687	99.658530	192.168.1.76	192.168.1.74	TCP	55	eisport > 61616 [PSH, ACK]
> Seq=18748 Ack=51560 Win=64483 Len=1	23687
> 23688	99.658591	192.168.1.76	192.168.1.74	TCP	55	eisport > 61616 [PSH, ACK]
> Seq=18749 Ack=51560 Win=64483 Len=1	23688
> 23689	99.658690	192.168.1.74	192.168.1.76	TCP	60	61616 > eisport [ACK]
> Seq=51560 Ack=18749 Win=16982 Len=0	23689
> .....
> 23928	99.675329	192.168.1.74	192.168.1.76	TCP	60	61616 > eisport [ACK]
> Seq=51560 Ack=18937 Win=16794 Len=0	23928
> 
> --> Next message
> 23929	100.623848	192.168.1.74	192.168.1.76	TCP	580	61616 > eisport [PSH,
> ACK] Seq=51560 Ack=18937 Win=16794 Len=526	23929
> 
> The second column is the Wireshark time, so the 580 byte message appears at
> 99.657686 and the first of the small packets at 99.658418 (a
> subscriber->broker packet - I guess "eisport" is Wireshark's attempt to
> interpret the ephemeral return port number).
> 
> But as I mentioned these additional mystery packets are *only *seen if
> wireFormat.tightEncodingEnabled=true, otherwise the number of packets per
> message comes down to 3.
> 
> However my main concern is the message packet size itself rather than the
> additional 'chatter'. The minimum message size I've managed to achieve so
> far, which is for a type-less, parameter-less, body-less message is 329
> bytes of data (383 bytes on the wire). That seems like a huge overhead when
> only sending small status messages comprising a few properties (obviously
> less of a concern if the message body runs into many KB or MB).
> 
> Are there any further options for reducing this size ?
> 
> Thanks again -
> 
> --
> View this message in context: http://activemq.2283324.n4.nabble.com/Message-bandwidth-overheads-how-to-reduce-tp3718866p3721276.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.



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