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From "Richard Eigenmann (JIRA)" <j...@apache.org>
Subject [jira] [Created] (JCS-123) Memory Cache with no disk auxiliary: map size doesn't change after initial puts
Date Sun, 04 May 2014 11:23:14 GMT
Richard Eigenmann created JCS-123:
-------------------------------------

             Summary: Memory Cache with no disk auxiliary: map size doesn't change after initial
puts
                 Key: JCS-123
                 URL: https://issues.apache.org/jira/browse/JCS-123
             Project: Commons JCS
          Issue Type: Question
          Components: Composite Cache
    Affects Versions: jcs-2.0.0
         Environment: Testing
            Reporter: Richard Eigenmann
            Priority: Minor
             Fix For: jcs-2.0.0


Curious how JCS handles different memory footprints under varying loads and configurations
I built a trivial JFrame that allows me to load a specific number of objects into the cache
and then randomly gets them on a timer every few hundred milliseconds. I print out the cache
statistics (.getStats()) periodically. 

I observed if I add 10 objects to the cache through a for loop, the map size jumps from 0
to 10 and stabilises there (cache.ccf allows 1000). The 10 objects are in the cache and the
timer thread gets them just fine when it asks for them. If I add another 10 objects these
10 objects do not get added to the cache and are not available for the timer thread to get
them whilst the first 10 are good.

If I start with say 1000 objects, the map size initialises at 1000 (assuming the ccf config
allows 1000 objects). These 1000 initialise and stay and any additional ones don't.

It looks like whatever number of objects come in first in rapid succession sets the size of
the memory-only cache.

Is this expected behaviour? I tried the other memory cache types too and seem to get the same
reaction. Would this be different if I had a disk auxiliary? (I am caching jpg files from
disk so loading them to a cache and writing them to disk auxiliary makes no real sense.)



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