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https://issues.apache.org/jira/browse/HIVE-13255?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15216925#comment-15216925
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Prasanth Jayachandran commented on HIVE-13255:
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3 perf related issues found in FloatTreeReader.nextVector().
1) i2l java bytecode found in inner loop. batchSize is long and loop index is
int. This inserts integer 2 long casts in inner loop
2) SerializationUtils.readFloat() has 4 invokevirtual whereas a readDouble has
only one as readFloat is not buffered
3) The JVM bytecode size for FloatTreeReader.nextVector() is 334 bytes which
will prevent this method from being inlined though being hot (has to less than
325 bytes for hot method inlining)
cc/ [~gopalv]
> FloatTreeReader.nextVector is expensive
> ----------------------------------------
>
> Key: HIVE-13255
> URL: https://issues.apache.org/jira/browse/HIVE-13255
> Project: Hive
> Issue Type: Bug
> Components: ORC
> Affects Versions: 2.1.0
> Reporter: Prasanth Jayachandran
> Assignee: Prasanth Jayachandran
> Attachments: bytecode-size-after.png, bytecode-size-before.png,
> float-reader-perf.png, q1-bottleneck.png, q1-warm-perf-map.png
>
>
> Some TPCDS queries on 1TB scale shows FloatTreeReader on profile samples. It
> is most likely because of multiple branching and polymorphic dispatch in
> FloatTreeReader.nextVector() implementation. See attached image for sampling
> profile output.
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