[jira] [Commented] (HBASE-11425) Cell/DBB end-to-end on the read-path

["Anoop Sam John (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-11425?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14050050#comment-14050050 ] 

Anoop Sam John commented on HBASE-11425:
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Yes we need ref counting.  The MemstoreSlab chunk pool is having a similar need and doing the ref counting way.
bq.Any idea of how much slower an offheap merge sort will be doing BB#get (or BR#get)? I'm up for doing a bit of measuring....
Not done any compare test.  Will do some plain test doing just key compare(millions of times) reading from DBB and HBB(This will use the unsafe compare).  Got into some bug fixes on visibility.  Will start again next week.  That will be great if u can measure boss.

> Cell/DBB end-to-end on the read-path
> ------------------------------------
>
>                 Key: HBASE-11425
>                 URL: https://issues.apache.org/jira/browse/HBASE-11425
>             Project: HBase
>          Issue Type: Umbrella
>          Components: regionserver, Scanners
>    Affects Versions: 0.99.0
>            Reporter: Anoop Sam John
>            Assignee: Anoop Sam John
>
> Umbrella jira to make sure we can have blocks cached in offheap backed cache. In the entire read path, we can refer to this offheap buffer and avoid onheap copying.
> The high level items I can identify as of now are
> 1. Avoid the array() call on BB in read path.. (This is there in many classes. We can handle class by class)
> 2. Support Buffer based getter APIs in cell.  In read path we will create a new Cell with backed by BB. Will need in CellComparator, Filter (like SCVF), CPs etc.
> 3. Avoid KeyValue.ensureKeyValue() calls in read path - This make byte copy.
> 4. Remove all CP hooks (which are already deprecated) which deal with KVs.  (In read path)
> Will add subtasks under this.



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