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From Jörn Kottmann <>
Subject Pure Active Master Slave completely hangs when slave throttles
Date Thu, 05 Nov 2009 13:02:08 GMT

we have a pure master slave broker (activemq 5.3.0) because we need HA 

The broker has a topic with one subscribe and a queue. The topic
receives xml messages which are written to a database by the subscriber
and afterwards a notification is send to the queue which just contains 
the message id.

I started with the default configuration and only modified it as 
described in
the pure master slave documentation, but the default contains
<policyEntry topic=">" producerFlowControl="true" memoryLimit="1mb">
<policyEntry queue=">" producerFlowControl="true" memoryLimit="1mb">,
the small memory limit caused throttling in the slave for the topic, at 
least this log
entry appeared on the slave:

 INFO | Usage Manager memory limit reached for topic://MessageFeed. 
Producers will be throttled to the rate at which messages are removed 
from this destination to prevent flooding it. See for more info

Afterwards the master was just hanging and dequeuing messages from the topic
or the queue was not possible.

I increased the memory limit but and gave the slave a little more 
memory, but is
that enough to make sure it cannot happen again ? Is there a way that 
the slave can
just fail if something goes wrong and not block the master ?

I also would love to learn how a slave can be re-attached to the master 
in case
the slave machine fails, the documentation only describes what must be done
to recover from a master failure (but maybe I missed something).



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