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From walec51>
Subject Re: What does the topic size attribute actually mean ?
Date Mon, 07 Dec 2009 14:07:02 GMT

Thank for your reply

fehm wrote:
> 1. Unless you have switched message persistency off, messages are always
> stored before distribution to subscribers. If you have disabled spooling
> messages to disk, it's very likely to fill up the Broker memory.
> 1. <lastImageSubscriptionRecoveryPolicy/> works only for retroactive
> subscriptions, means that only if your clients have 'retroactive=true'
> enabled they will see -independent of when a message has been sent- always
> the last one. Again ,this means that the server will store the message
> until a new one comes in. Do have a large number of topics ?
> 2. Of course a memory leak can always happen due to a bug in the server.
> However, before you should check that your clients "behave well". Make
> sure that they don't have resource leaks (e.g. not closing
> subscription/connection objects). Unfortunately, I once ran into this and
> banged my head against the wall for a while. 
> Watch the subscription stats (inflight count is a good indicator, that the
> client makes problems). I recommend to use the jconsole to check these
> numbers.
> How many topics do you use/create. Remember that if the server will always
> keep your topic, hence using memory. In my experience, with 50K topics you
> need > 1024M JVM size for sure.

1. I switched the persistency off and jest I have a large number of topic.
They are created dynamically and the inactive ones are deleted from time to
time. The problem is that the memory usage doesn't seam to decrease then
they get deleted.

2. Thanks to the clue ! I'll look in to this.

PS. Shouldn't the server just delete the messages in the topic if it has not
durable consumers and all the normal consumers have disconnected ?

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