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From Tim Bain <tb...@alumni.duke.edu>
Subject Re: The size of KahaDB doesn't seem to decrease
Date Fri, 17 Mar 2017 13:46:07 GMT
No, indexCacheSize is not a limit on the size of the index. It specifies
how much of the index should be stored in memory (which is fast); if that's
not enough to hold the full index, the remaining content will be paged in
from db.data on disk (which is slow).

As I understand it, db.data grows only based on the max number of live
messages and the number of live destinations (topics, for you), so the only
way to limit it is to ensure that messages are consumed promptly, and to
promptly GC any destinations you no longer need (this only applies if you
continually create and discard short-lived destinations, which may not be
how you use ActiveMQ).

But let's step back for a second: why are you trying to limit the size of
db.data in the first place? Why is its current size a problem?

Tim

On Mar 17, 2017 1:32 AM, "Hidekazu" <hi_decaf@yahoo.co.jp> wrote:

Dear cschneider

Thanks to your advice, we could delete data.db safely.

I found that activemq.xml had a parameter which limits the cache size.
Is the parameter below perhaps for db.data?
Or is it different from the limit for db.data because it explains that
"cached in memory."

------------
http://activemq.apache.org/kahadb.html
  indexCacheSize
  10000
  Number of index pages cached in memory.
------------

I would appreciate if you know activemq has a parameter to limit the size of
data.db and tell me it.

Anyway, you are my ActiveMQ teacher.
I understand ActiveMQ more than before thanks to you.

Kawai



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