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MQSeries.net Forum Index » General IBM MQ Support » MQSeries performance - IO BUG?

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dschnaider
PostPosted: Thu Feb 07, 2002 5:03 am    Post subject: Reply with quote

Newbie

Joined: 06 Feb 2002
Posts: 5

When testing MQSeries performance with a HP machine with 8 CPU's, 8GB of
memory, fibre channel... etc...
We found some very big performance problem.

One problem that we find out is that when you put 10 messages and then
commit (it can be any number of messages, let say n) MQseries will make
N*2 IO's to the disk. When first they write each header (just 8 bytes
long) and then the body (in my case 4KB). The fibre channel uses blocks
of 16KB... It is a big performance problem.

is there a way fix it?
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ChrisW
PostPosted: Thu Feb 07, 2002 6:10 am    Post subject: Reply with quote

Voyager

Joined: 20 May 2001
Posts: 78
Location: UK

When I did some perfomance testing on HP-UX under 5.1, the main problem seemed to be the amqzlaa0 process which consumed more and more cpu (almost 100%) but the test got progressively slower and slower (I can't remember the exact figures but say started at 100 messages a second, and at the end of the test less than 1 a second).

I have not repeated the tests under 5.2 but have noticed that now multiple amqzlaa0's get spawned as required, although under heavy useage I have seen the processes again take a lot of CPU.

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dschnaider
PostPosted: Thu Feb 07, 2002 7:06 am    Post subject: Reply with quote

Newbie

Joined: 06 Feb 2002
Posts: 5

Do you know what this process do?
Did you try to fix it somehow?

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ChrisW
PostPosted: Fri Feb 08, 2002 4:55 am    Post subject: Reply with quote

Voyager

Joined: 20 May 2001
Posts: 78
Location: UK

amqzlaa0 is called the Queue Manager Agent address space in the manuals and is used to protect the Queue Manager from "untrusted" applications who connect via this process.

It's a shame that the channel processes themselves go through this. Maybe there is a peformance enhancement in making channels trusted?

This is only a brief explaination of the process - I am sure others in the forum can add a more detailed description.
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