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I need to get rough estimation of memory usage of my Infinispan cache ( which is implemented using version 5.3.0) - ( For learning purposes )

Since there is no easy way to do this, I came up with following procedure.

Add cache listener to listen cache put/remove events and log the size of inserted entry using jamm library which uses java.lang.instrument.Instrumentation.getObjectSize. But i'm little skeptical about it, whether it returns right memory usage for cache. Am I doing this measurement correctly ? Am I missing something here or do I need consider more factors to do this ?

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Viraj
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1 Answers1

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If you don't need real-time information, the easiest way to find the actual memory usage is to take a heap dump and look at the cache objects' retained sizes (e.g. with Eclipse MAT).

Your method is going to ignore the overhead of Infinispan's internal structures. Normally, the per-entry overhead should be somewhere around 150 bytes, but sometimes it can be quite big - e.g. when you enable eviction and Infinispan allocates structures based on the configured size (https://issues.jboss.org/browse/ISPN-4126).

Dan Berindei
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