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From "James Strachan" <james.strac...@gmail.com>
Subject Re: 4.0 Consumer OutOfMemoryError bug?
Date Wed, 14 Jun 2006 13:32:07 GMT
On 6/13/06, jevans12 <jevans12@harris.com> wrote:
> Are prefetch policy and optimized ack's Autonomous?

Yes, they are independent features. Prefetch policy is the maximum
number of unacknowledged messages delivered to a client by the broker.

optimized ack is an option to delay sending individual acks but send batches.


> As I see a consumer will
> ask for 65% of the prefetch policy messages.

The broker sends the entire prefetch size of messages to a client as
fast as possible; the client doesn't ask for messages per se - other
than subscribing with a prefetch value.


>  Does the batching of ack's
> follow this? as I receive the 65th (of 100) message a batch ack will be sent
> for those 65?

I'd have to noodle around the code but yes if enabled then optimize
acks sends in batches.

Though folks have experienced some problems with optimize acks...
http://issues.apache.org/activemq/browse/AMQ-716

so it might be worth disabling them (I've added this to the 4.0 release notes).

-- 

James
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http://radio.weblogs.com/0112098/

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