[jira] [Commented] (HBASE-17484) Add non cached version of OffheapKV for write path

["ramkrishna.s.vasudevan (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-17484?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15855367#comment-15855367 ] 

ramkrishna.s.vasudevan commented on HBASE-17484:
------------------------------------------------

Finally after all the different test cases executed we have come to the conclusion that atleast in the Memstore case where we do millions of comparisons in a write heavy work load, we found that having the same type of Cell instance makes the comparisons faster rather than one being KV and other being offheap KV. More details in follow on JIRA. 
So the decision was that to make OffheapKV also similar to KV in terms of caching (means we won't be adding anything as state variables in OffheapKV) and just leave it as how KV works.
Also in the follow on JIRA after we copy the cell to MSLAB we will return a cell of OffheapKV type only. I think it is better we rename to ByteBufferCell so that it can be a cell backed by onheap /offheap cells.


> Add non cached version of OffheapKV for write path
> --------------------------------------------------
>
>                 Key: HBASE-17484
>                 URL: https://issues.apache.org/jira/browse/HBASE-17484
>             Project: HBase
>          Issue Type: Sub-task
>          Components: regionserver
>    Affects Versions: 2.0.0
>            Reporter: ramkrishna.s.vasudevan
>            Assignee: ramkrishna.s.vasudevan
>             Fix For: 2.0.0
>
>         Attachments: HBASE-17484.patch
>
>
> After running lot of different performance tests for various scenarios and with multi threads we thought that is  better to have a version of OffheapKV in write path that does not cache anything and its fixed_overhead is equal to that in KeyValue. 



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