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https://issues.apache.org/jira/browse/KUDU-2017?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Todd Lipcon resolved KUDU-2017.
-------------------------------
Resolution: Fixed
Fix Version/s: 1.4.0
fixed in e1104e4b8e64459d6a90c24d41ccc764d377c85c
> Incorrect calculation determining performance improvement for flush
> -------------------------------------------------------------------
>
> Key: KUDU-2017
> URL: https://issues.apache.org/jira/browse/KUDU-2017
> Project: Kudu
> Issue Type: Bug
> Components: tablet
> Affects Versions: 1.3.1
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Fix For: 1.4.0
>
>
> The code to calculate the MM "perf improvement score" for a flush had two
> bugs:
> (1) we calculated {{threshold - current_usage}} instead of {{current_usage -
> threshold}}, which resulted in a negative score
> (2) we had an unsigned integer overflow, which resulted in the above negative
> score becoming insanely large
> These two wrongs "made a right" in which we'd still trigger flushes at the
> flush threshold, which is why this went unnoticed for quite some time.
> However, the flushing behavior is more aggressive than originally intended,
> and we would lose the correct prioritization of flushing tablets that are
> farther above the threshold.
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