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Posted to issues@hive.apache.org by "Prasanth Jayachandran (JIRA)" <ji...@apache.org> on 2018/05/17 07:50:00 UTC
[jira] [Comment Edited] (HIVE-19578) HLL merges tempList on every
add
[ https://issues.apache.org/jira/browse/HIVE-19578?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16478651#comment-16478651 ]
Prasanth Jayachandran edited comment on HIVE-19578 at 5/17/18 7:49 AM:
-----------------------------------------------------------------------
Ran a quick benchmark with following scenarios
{code:java}
testHLLAddHive - Current Hive implementation that uses TreeMap for HLL Sparse Register
testHLLAddInt2ByteSortedMap - TreeMap replaced with Int2ByteSortedMap for HLL Sparse Regsiter
testHLLTreeMapPlusOpt - TreeMap + branch optimizations in HLL add() inner loop
testHLLAddInt2ByteSortedMapPlusOpt - Int2ByteSortedMap + branch optimizations in HLL add() inner loop{code}
{code:java}
Benchmark Mode Cnt Score Error Units
HyperLogLogAdd.testHLLAddInt2ByteSortedMapPlusOpt avgt 10 12.773 ± 0.382 ns/op
HyperLogLogAdd.testHLLAddInt2ByteSortedMap avgt 10 25.675 ± 0.439 ns/op
HyperLogLogAdd.testHLLTreeMapPlusOpt avgt 10 21.978 ± 0.562 ns/op
HyperLogLogAdd.testHLLAddHive avgt 10 37.559 ± 0.488 ns/op{code}
was (Author: prasanth_j):
Ran a quick benchmark with following scenarios
{code:java}
testHLLAddHive - Current Hive implementation that uses TreeMap for HLL Sparse Register
testHLLAddInt2ByteSortedMap - TreeMap replaced with Int2ByteSortedMap for HLL Sparse Regsiter
testHLLAddInt2ByteSortedMapPlusOpt - Int2ByteSortedMap + branch optimizations in HLL add() inner loop{code}
{code:java}
Benchmark Mode Cnt Score Error Units
HyperLogLogAdd.testHLLAddInt2ByteSortedMapPlusOpt avgt 10 12.773 ± 0.382 ns/op
HyperLogLogAdd.testHLLAddInt2ByteSortedMap avgt 10 25.675 ± 0.439 ns/op
HyperLogLogAdd.testHLLAddHive avgt 10 37.559 ± 0.488 ns/op{code}
> HLL merges tempList on every add
> --------------------------------
>
> Key: HIVE-19578
> URL: https://issues.apache.org/jira/browse/HIVE-19578
> Project: Hive
> Issue Type: Bug
> Reporter: Sergey Shelukhin
> Assignee: Prasanth Jayachandran
> Priority: Major
> Attachments: Screen Shot 2018-05-16 at 15.29.12 .png
>
>
> See comments on HIVE-18866; this has significant perf overhead after the even bigger overhead from hashing is removed. !Screen Shot 2018-05-16 at 15.29.12 .png!
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