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https://issues.apache.org/jira/browse/KUDU-749?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16854764#comment-16854764
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Todd Lipcon commented on KUDU-749:
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Hi [~ZhangYao]. That makes sense to me -- maybe the POC will expose some issue
that we aren't thinking about, but it's worth trying.
Another thing you could try is to implement "seek before": eg if you are
looking for the latest delta on row 10, seek instead to row 11 ts=0, and then
scan left by one entry. This should be possible to implement in O(lgn) time.
> Improve performance for zipfian update
> --------------------------------------
>
> Key: KUDU-749
> URL: https://issues.apache.org/jira/browse/KUDU-749
> Project: Kudu
> Issue Type: Improvement
> Components: perf, tablet
> Affects Versions: Private Beta
> Reporter: Todd Lipcon
> Priority: Major
> Attachments: screenshot-1.png, screenshot-2.png
>
>
> A zipfian 50/50 update/read workload on YCSB gets slower and slower until
> it's pretty intolerable (random reads taking 100+ms of CPU). It seems like
> all the CPU is spent in DMSIterator::PrepareBatch. We're probably doing
> something dumb here - let's look for some low hanging fruit to fix this.
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