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https://issues.apache.org/activemq/browse/AMQ-2532?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=56435#action_56435
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Fabrice Delaporte commented on AMQ-2532:
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Ah, yes indeed, this is fixed. Good news !
Strange it didn't strike me that I should try the latest snapshots before
reporting ;)
Sorry for the noise.
Cheers,
Fabrice
> Broker paging all available messages from store leading to resource exhaustion
> ------------------------------------------------------------------------------
>
> Key: AMQ-2532
> URL: https://issues.apache.org/activemq/browse/AMQ-2532
> Project: ActiveMQ
> Issue Type: Bug
> Components: Broker
> Affects Versions: 5.3.0
> Environment: Java 1.6
> Reporter: Fabrice Delaporte
>
> There seems to be a regression (works fine in 5.2.0) related to the fix for
> the following:
> https://issues.apache.org/activemq/browse/AMQ-2413
> I think the intent of the original code was to prevent uncontrolled paging of
> pending messages. The doPageIn method is called in version 5.3.0 :
> - each time a message is acked/committed
> - each time the MemoryUsage is decreased
> As a result, if you create a queue with, say, 1 000 000 messages in it, then
> start a consumer, the broker will try to page in all the messages from the
> store as consuming goes on (with default configuration values, 200 paged in
> messages for one consumed message minimum - I say minimum because if the
> MemoryUsage is decreased when you consume a message, then doPageIn is invoked
> again). Guaranteed OutOfMemoryError as in general consuming messages is
> slower than paging from store. I guess the same can occur when you have a
> fast producer and a slow consumer, without producer flow control.
> I would say that in any case, the broker should never page in more messages
> than the maxPageSize attribute, plus the number of dispatched messages. More
> formally:
> {code:java}
> int toPageIn = getMaxPageSize() - pagedInPendingDispatch.size();
> {code}
> And just to make sure we never get a negative value:
> {code:java}
> int toPageIn = Math.max(0, getMaxPageSize() -
> pagedInPendingDispatch.size());
> {code}
> Note 1: this behavior is also exhibited by the background message expiration
> logic, that forces message pagination each time it is run. With big queues
> without consumers, by default you'll get 200 more messages paginated each
> time the expiration task is run. Eventually leading to broker resource
> exhaustion if no consumer comes into play in the near future with active
> producers queuing up messages.
> Note 2: this may also be related to
> https://issues.apache.org/activemq/browse/AMQ-2468
> Workarounds:
> - setting lazyDispatch to true fixes the problem for message consuming only
> - background expiration can be disabled by setting expireMessagesPeriod to -1
> Cheers,
> Fabrice
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