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https://issues.apache.org/jira/browse/HBASE-12345?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14184436#comment-14184436
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Anoop Sam John commented on HBASE-12345:
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Yep. As per the test I have done in HBASE-11425. Added comment there. Just
copying that comment to here
{quote}
Testing with a 2 million Cells with single cell per row.
Writing all cells to a BB/DBB and trying a seek with to last kv. (To make
compare across all cells in BB/DBB)
Seek code is like what we have in ScannerV3#blockSeek
with RK length 17 bytes (1st 13 bytes are same) Getting almost same result.
With RK length 117 bytes (1st 113 bytes are same) the DBB based read is ~3%
degrade
{quote}
Well in this test, the read and compare were from HBB and DBB and those are
almost same.
In case of our CellComparator we have Unsafe based optimization. In my old test
this was not in use. With Unsafe based read from HBB#array() [this is what
happens in HFileReaderV2/V3] there is a significant perf diff with DBB. Here RK
length of 117 bytes and 2 millions cells and we seek to last cell, the DBB test
is 50% slower.
I am thinking of doing Unsafe based compares for data in DBB as well.
Just done Unsafe based access from DBB/HBB and then we are in a better shape.
The DBB based above test is ~12% slower than old HBB.array() based compares.
Will raise a subtask and attach the approach there.
> Unsafe based Comparator for BB
> -------------------------------
>
> Key: HBASE-12345
> URL: https://issues.apache.org/jira/browse/HBASE-12345
> Project: HBase
> Issue Type: Sub-task
> Components: regionserver, Scanners
> Reporter: Anoop Sam John
> Assignee: Anoop Sam John
> Attachments: HBASE-12345.patch
>
>
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