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https://issues.apache.org/jira/browse/HBASE-13819?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14909305#comment-14909305
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Anoop Sam John commented on HBASE-13819:
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Yes these DBBs are any way allocated but thrown away after the wire transfer.
But in BoundedBBPool, we will keep these buffers. We will have by default, 2
MB max size and 2 * handlers count such buffers. We will keep them for the
life of RS. That is what I was thinking, the diff will be. wdyt?
> Make RPC layer CellBlock buffer a DirectByteBuffer
> --------------------------------------------------
>
> Key: HBASE-13819
> URL: https://issues.apache.org/jira/browse/HBASE-13819
> Project: HBase
> Issue Type: Sub-task
> Components: Scanners
> Reporter: Anoop Sam John
> Assignee: Anoop Sam John
> Fix For: 2.0.0
>
> Attachments: HBASE-13819.patch
>
>
> In RPC layer, when we make a cellBlock to put as RPC payload, we will make an
> on heap byte buffer (via BoundedByteBufferPool). The pool will keep upto
> certain number of buffers. This jira aims at testing possibility for making
> this buffers off heap ones. (DBB) The advantages
> 1. Unsafe based writes to off heap is faster than that to on heap. Now we are
> not using unsafe based writes at all. Even if we add, DBB will be better
> 2. When Cells are backed by off heap (HBASE-11425) off heap to off heap
> writes will be better
> 3. When checked the code in SocketChannel impl, if we pass a HeapByteBuffer
> to the socket channel, it will create a temp DBB and copy data to there and
> only DBBs will be moved to Sockets. If we make DBB 1st hand itself, we can
> avoid this one more level of copying.
> Will do different perf testing with changed and report back.
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