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https://issues.apache.org/jira/browse/KUDU-2847?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16866241#comment-16866241
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Todd Lipcon commented on KUDU-2847:
-----------------------------------
After optimizing predicate evaluation (KUDU-2846) this is now about 20% of the
scanner thread CPU for TPCH Q6
> Optimize iteration over selection vector in SerializeRowBlock
> -------------------------------------------------------------
>
> Key: KUDU-2847
> URL: https://issues.apache.org/jira/browse/KUDU-2847
> Project: Kudu
> Issue Type: Improvement
> Components: perf, tserver
> Reporter: Todd Lipcon
> Priority: Major
>
> Currently, SerializeRowBlock operates column-by-column, which means we have
> to iterate over the selection bitmap once for each column. This code isn't
> particularly well optimized -- in TPCH Q6, about 10% of CPU is spent in
> BitmapFindFirst. We should look at alternate implementations here that better
> amortize the bitmap iteration cost across all of the columns and generally
> micro-optimize it.
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