memory-management,jvm,ehcache , Does ehcache reserve (allocate) heap memory set with maxBytesLocalHeap?


Does ehcache reserve (allocate) heap memory set with maxBytesLocalHeap?

Question:

Tag: memory-management,jvm,ehcache

I use ehache 2.8.

I am not sure I understand the documentation correctly regarding reservation of the memory for the cache.

Is the memory set in ehcache.xml like this:

<ehcache maxBytesLocalHeap="256M">

(...)

</ehcache>

..actually being allocated at start and this cache will use exactly 256MB of heap or does this only mean (like it should, if this attribute is named like it is) that this cache can take at most 256MB of heap?


Answer:

This means that this cache will do its best to contain 256MB or less of user data. The actual memory footprint of the cache can be larger due to internal data structures.

Also in case the cache operates at full capacity, it may go over size while eviction takes place.


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