Using custom backing map for distributed scheme

Question

Hallo,
We are evaluating usage of distributed scheme for storing large amount of data. We have analyzed memory usage for distributed-scheme backed by local-scheme (with binary unit calculator) and received interesting results.
On single JVM
110M - byte arrays - our data in binary form
20M - com.tangosol.util.Binary objects - overhead of binary objects to wrap byte arrays
27M - com.tangosol.net.cache.LocalCache$Entry objects - local cache entry overhead
When we have tried our own implementation of java.util.Map as backing map (using some clever tricks to get smaller size at the cost of CPU processing)
On single JVM
36M - byte arrays - out application data
So it is look like we are going to stick with our implementation.
My question
Are there any known drawbacks of using implementation of java.util.Map as backing map for distribute-scheme?
Our implementation is thread safe of cause (we have already tested it thread-count option of distributed-scheme)

Answer 1

Hi Alexey,
alexey.ragozin wrote:
But I already have this table in first map (String -> Binary), in former project we have used handmade Map implementation with method internKey() to avoid duplication of data.
I'm looking for a way to reuse our old and proven techniques with coherence caches.
Thank you,
AlexeyUnfortunately there is no way the extractor could get hold of the already existing key reference in the reverse index. I agree that the extracted value reference in the reverse index entry (the key from that entry) should be reused by Coherence as the forward index value if the reverse index entry for the same extracted value exists, but apparently it is not.
Try to submit an enhancement request for this (and please share the ticket number for it so we can also look for it in the release notes).
Best regards,
Robert