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https://issues.apache.org/jira/browse/HBASE-15077?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15093271#comment-15093271
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Anoop Sam John commented on HBASE-15077:
----------------------------------------
Test failures seems not related.
No new findbugs with this patch.. Other complaints of javac etc seems some
issue with calculation in the reporting.
Will commit now.. Thanks for the reviews.
> Support OffheapKV write in compaction with out copying data on heap
> -------------------------------------------------------------------
>
> Key: HBASE-15077
> URL: https://issues.apache.org/jira/browse/HBASE-15077
> Project: HBase
> Issue Type: Sub-task
> Components: regionserver, Scanners
> Reporter: Anoop Sam John
> Assignee: Anoop Sam John
> Fix For: 2.0.0
>
> Attachments: HBASE-15077.patch, HBASE-15077_V2.patch,
> HBASE-15077_V2.patch, HBASE-15077_V3.patch
>
>
> HBASE-14832 is not enough to handle this. Doing the remaining needed here.
> {code}
> if (cell instanceof ByteBufferedCell) {
> 890 out.writeShort(rowLen);
> 891 ByteBufferUtils.copyBufferToStream(out, ((ByteBufferedCell)
> cell).getRowByteBuffer(),
> 892 ((ByteBufferedCell) cell).getRowPosition(), rowLen);
> 893 out.writeByte(fLen);
> 894 ByteBufferUtils.copyBufferToStream(out, ((ByteBufferedCell)
> cell).getFamilyByteBuffer(),
> 895 ((ByteBufferedCell) cell).getFamilyPosition(), fLen);
> 896 ByteBufferUtils.copyBufferToStream(out, ((ByteBufferedCell)
> cell).getQualifierByteBuffer(),
> 897 ((ByteBufferedCell) cell).getQualifierPosition(), qLen);
> {code}
> We have done this but it is not really helping us!
> In ByteBufferUtils#copyBufferToStream
> {code}
> public static void copyBufferToStream(OutputStream out, ByteBuffer in,
> int offset, int length) throws IOException {
> if (in.hasArray()) {
> out.write(in.array(), in.arrayOffset() + offset,
> length);
> } else {
> for (int i = 0; i < length; ++i) {
> out.write(toByte(in, offset + i));
> }
> }
> }
> {code}
> So for DBB it is so costly op writing byte by byte reading each to on heap.
> Even if we use writeByteBuffer(OutputStream out, ByteBuffer b, int offset,
> int length), it won't help us as the underlying stream is a
> ByteArrayOutputStream and so we will end up in copying.
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