Limit to high-units for 64bit JVM?

Question

Hi all,
I'm doing some testing on 3.4.1 with a 64bit JVM and a large storage node. I have the JVM starting up fine with a min/max memory footprint of 17GB. I have one distributed cache defined as such:
<distributed-scheme>
<scheme-name>UDMessagesDistributedScheme</scheme-name>
<service-name>UDMessagesDistributedScheme</service-name>
<autostart>true</autostart>
<backing-map-scheme>
<local-scheme>
<scheme-name>UDMessagesDistributedInMemoryScheme</scheme-name>
<!-- 17GB JVM - 800MB applciation -->
<high-units>17414750208</high-units>
<eviction-policy>HYBRID</eviction-policy>
<unit-calculator>BINARY</unit-calculator>
</local-scheme>
</backing-map-scheme>
<backup-count>0</backup-count>
</distributed-scheme>
Nothing complains, but when I browse the JMX GUI, the <high-units> reported is reduced to 234881024, and pruning happens as if this byte size (about 225MB) is being used.
What I'm guessing is that <high-units> is represented as an Integer that has a max value of 2^31 - 1 that is smaller than my requested size. But if I'm using a 64bit JVM, the max should be 2^63 - 1, which is plenty big for my value.
Does anyone have any experience with storage nodes of this size, or suggestions how to utilize this space?
Thanks!

Answer 1

Hi
Yes this is something that will be fixed in the next release of Coherence. In version 3.5 we introduced unit factor to handle large values for the binary calculator. So the high-units can be paired with a unit-factor element.
If you want to look more at the documentation http://coherence.oracle.com/display/COH35UG/local-scheme.
The current plan is that the high-units will be a long (64 bit) in the next major release of Coherence (4.0).
Thanks
/Charlie