[
https://issues.apache.org/jira/browse/HBASE-15721?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15549445#comment-15549445
]
Anoop Sam John commented on HBASE-15721:
----------------------------------------
bq.we remove this deprecation which seems to be a regression:
Not really.. The thing is in Cell there can not be any thing like a keybuffer
of single buffer. But KV, we know is based on single buffer backed. So a
getter for buffer there seems valid only. KV is private marked also. We have
moved to Cell only flows in read and write paths. KV is having stuff like
getKeyLength, getKeyOffset. These were never deprecated also.. The thing was
that we were using KV.getBuffer through out our code in 0.96 time. But now
things are clean. So IMHO, the getBuffer () in KV is making sense very much.
If u strongly feel we should not remove deprecation I can undo that in this
patch.. I just came across this API in this patch and thought there is no point
in marking it as deprecated.
Ya we copy the cell into the buf in KV format only. As long as there is no
other kind of Cell impl, we will have to continue with these stuff..
> 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,
> HBASE-15721_V3.patch, HBASE-15721_V4.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.
> Also avoid lots of garbage while doing this MSLAB copy. With every cell, we
> used to create a ByteRange instance to pass the allocated chunk + offset from
> MSLAB to Segment. Now we can make the MSLAB impl to do the allocation and
> copy of the cell so that one object creation per cell addition can be avoided.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
