Hey John,
So we had a problem recently that we debugged into and the concept of
credits is related to flow control implemented by the broker. We had a
situation where under load and potentially due to something else going
on our side where messages stopped being delivered all together.
And in the debugger we found the credit system was actually preventing
delivery of the messages. But it was too complicated for me to piece
together exactly why. In our situation, the system didn't seem to
recover and deliver messages again without a restart -- or maybe it just
took longer than we were willing to wait. When we turned off the flow
control, the problem completely went away. We do have some logical flow
control on the outside of our use of the broker, so it is not like we're
completely without flow control.
Just where you said stuff kind of hangs and doesn't deliver until it
recovers after 30 seconds and those credit messages are present it
seemed to resonate a bit with what we had seen recently. (I am not deep
enough in technical understanding of all aspects of the broker to know
for sure, so apologies if this is chatter that misdirects your thinking).
Best of luck,
David.
On 3/20/23 9:58 AM, John Lilley wrote:
Hi David,
If by that you mean lines like:
2023-03-18T03:01:57.255 [HpaMetrics-Background]
AbstractProducerCreditsImpl.checkCredits:182
<ftp://AbstractProducerCreditsImpl.checkCredits/182> [] DEBUG - not
asking for -1 credits on activemq.management 2023-03-18T03:01:57.255
[HpaMetrics-Background] AbstractProducerCreditsImpl.afterAcquired:90
<ftp://AbstractProducerCreditsImpl.afterAcquired/90> [] DEBUG -
AfterAcquire 413 credits on address activemq.management
I don't get the feeling those actually hurt anything because they
happen all the time. But I really don't know what they are.
John
rg <https://www.redpointglobal.com/>
John Lilley
Data Management Chief Architect, Redpoint Global Inc.
888 Worcester Street, Suite 200 Wellesley, MA 02482
*M: *+1 7209385761 <tel:+1 7209385761> | john.lil...@redpointglobal.com
-----Original Message-----
From: David Bennion <dav...@gmx.com>
Sent: Sunday, March 19, 2023 6:09 PM
To: users@activemq.apache.org
Cc: Lewis Gass <lewis.g...@redpointglobal.com>
Subject: Re: Please help finding lost packet
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Those errors at the end feel awfully similar to an issue that we ran
into recently.
We resolved by disabling flow control by setting consumerWindowSize
and producerWindowSize both to -1 as I recall. Our end conclusion was
that the flow control stuff in the broker was getting confused and
then declining to deliver messages. This would only happen under heavy
load.
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