Increasing Duplicate ID Cache size

[Rahul Amaram <ra...@lithium.com>]

Hi,

Due to the requirement of being able to store a large number of messages 
in the queue without duplicates, I am considering increasing the 
duplicate id cache size (parameter: id-cache-size) from its default 
value of 2000 to a million. While I know that this would require 
additional memory, I am not sure of what other complications could I run 
into. I have looked up the forums but couldn't find any information 
about increasing the duplicate id cache size.

Is it ok to increase the duplicate id cache size or could it have some 
serious performance implications on ActiveMQ broker? Kindly advise.

Thanks,

Rahul.


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Re: Increasing Duplicate ID Cache size

[Clebert Suconic <cl...@gmail.com>]

I believe you are talking about ActiveMQ Artemis.

the duplicate detection is intended for in transit messages.. that
means.. in case you retry a send (say because of an error), the
duplicate would be ignored.. and you would then achieve Exactly Once
semantic without using transactions.
You could do something similar on your consumer side as well...


for that, you don't need to have your entire set of messages on the
duplicate cache.. just enough to guarantee your Exactly Once
semantics.. .1 Million wouldn't be efficient for 2 reasons: (The
HashMap would be too big), and the journal performance (IO) would also
be affected by the duplicate caches.




On Fri, Jul 7, 2017 at 7:13 AM, Rahul Amaram <ra...@lithium.com> wrote:
> Hi,
>
> Due to the requirement of being able to store a large number of messages in
> the queue without duplicates, I am considering increasing the duplicate id
> cache size (parameter: id-cache-size) from its default value of 2000 to a
> million. While I know that this would require additional memory, I am not
> sure of what other complications could I run into. I have looked up the
> forums but couldn't find any information about increasing the duplicate id
> cache size.
>
> Is it ok to increase the duplicate id cache size or could it have some
> serious performance implications on ActiveMQ broker? Kindly advise.
>
> Thanks,
>
> Rahul.
>
>
> --
> Email: rahul.amaram@lithium.com
> Mobile: +91 9866302502
> Skype: rahulamaram
> WebEx Personal Room: https://lithium.webex.com/join/rahul.amaramlithium.com
>



-- 
Clebert Suconic