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From Rob Davies <rajdav...@gmail.com>
Subject Re: Why do persistent messages exhaust memory and lock out consumers?
Date Thu, 11 Jun 2009 06:22:06 GMT
which version are you using ?
On 11 Jun 2009, at 01:48, Elliot Barlas wrote:

>
> Scenario:
> -Minimal AMQ message broker with persistence enabled and default usage
> values of 64 MB memory limit, 10 GB temp store limit, and 100 GB  
> persistent
> store limit
> -AMQ producer client sending 100 KB persistent messages to queue X  
> in a loop
> with a short sleep (roughly 10 msgs/second)
>
> Observations:
> -MemoryPercentUsage reaches 70% after a few minutes and remains there
> -StorePercentUsage remains at 0 (since persistent store limit is so  
> high)
> -Disk usage under persistent data directory increases as expected
>
>
> Why is the memory percent usage increasing so rapidly?  Shouldn't  
> messages
> go directly to the persistent store?  If memory is used, shouldn't  
> it be
> flushed once it reaches a certain threshold?
>
>
> Scenario continued:
> -A second AMQ producer client sending 100 KB persistent messages to  
> queue Y
> in a loop
> -AMQ consumer client consuming messages from queue Y in a loop
>
> Observations continued:
> -MemoryPercentUsage remains at 70%
> -StorePercentUsage remains at 0
> -Disk usage under persistent data directory continues to increase
> -NO messages dequeued from queue Y!
>
>
> Shockingly, messages are NOT consumed from queue Y in the scenario  
> described
> above.  Once the 70% memory usage threshold is reached, messages  
> cannot be
> consumed from queue Y.  After further testing, I have seen the  
> messages can
> be consumed from queue X, which decreased the memory percent used, and
> restores the system (messages can then be consumed from other queues).
>
> Why is this happening?  Has anyone else seen this?
>
> The same test with non-persistent messages is not problematic.  The  
> memory
> percent usage increases, but once it reaches 70% the messages are  
> flushed to
> the temp store and the percent usage is reduce to 0%
>
> Thanks,
> Elliot
> -- 
> View this message in context: http://www.nabble.com/Why-do-persistent-messages-exhaust-memory-and-lock-out-consumers--tp23973571p23973571.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>


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