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https://issues.apache.org/jira/browse/HBASE-15721?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15266979#comment-15266979
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stack commented on HBASE-15721:
-------------------------------
bq. So instead of allocating a chunk from interface and copy and recreate Cell
in memstore class, we can allocate and clone within the MSLAB impl. May be we
need change the comments on class.
I think you are changing MSLAB from being an allocator to instead being a
manager of the allocations; a change in responsibility. If so, lets work out
who does what and make roles clear.
Regards Streamable, it does seem like we need methods for
serializing/deserializing Cells. We can't use 'Writeable' since that type is
taken (and a mistake we'd like to not repeat). Where do we need Cell
Serialization and rehydration? From Streams/BBs and byte arrays?
Ok on the getBuffer.
> 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, HBASE-15721_V2.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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