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https://issues.apache.org/jira/browse/HBASE-15721?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15260001#comment-15260001
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Anoop Sam John commented on HBASE-15721:
----------------------------------------

Oh in the other work space have already an off heap implementation of MSLAB and 
so we have BB backing the chunks.  I will correct that.
Ya for trunk as of now, this can be byte[] based.
Later when we have off heaping in MSLAB also, we can change this byte[] to 
ByteBuffer.  All these are private interfaces and so no problem. Any way al 
changed in trunk alone.

> Optimization in cloning cells into MSLAB
> ----------------------------------------
>
>                 Key: HBASE-15721
>                 URL: https://issues.apache.org/jira/browse/HBASE-15721
>             Project: HBase
>          Issue Type: Sub-task
>          Components: regionserver
>            Reporter: Anoop Sam John
>            Assignee: Anoop Sam John
>             Fix For: 2.0.0
>
>         Attachments: HBASE-15721.patch
>
>
> Before cells added to memstore CSLM, there is a clone of cell after copying 
> it to MSLAB chunk area.  This is done not in an efficient way.
> {code}
> public static int appendToByteArray(final Cell cell, final byte[] output, 
> final int offset) {
>     int pos = offset;
>     pos = Bytes.putInt(output, pos, keyLength(cell));
>     pos = Bytes.putInt(output, pos, cell.getValueLength());
>     pos = appendKeyTo(cell, output, pos);
>     pos = CellUtil.copyValueTo(cell, output, pos);
>     if ((cell.getTagsLength() > 0)) {
>       pos = Bytes.putAsShort(output, pos, cell.getTagsLength());
>       pos = CellUtil.copyTagTo(cell, output, pos);
>     }
>     return pos;
>   }
> {code}
> Copied in 9 steps and we end up parsing all lengths.  When the cell 
> implementation is backed by a single byte[] (Like KeyValue) this can be done 
> in single step copy.



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