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https://issues.apache.org/jira/browse/CASSANDRA-6930?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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shobana updated CASSANDRA-6930:
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Comment: was deleted
(was: Hi
I am starting to work on this one. If there is someone already looking into it,
can you pl let me know so i can pick another one.
Thanks)
> Dynamic Snitch isWorthMergingForRangeQuery Doesn't Handle Some Cases Optimally
> ------------------------------------------------------------------------------
>
> Key: CASSANDRA-6930
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6930
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Reporter: Tyler Hobbs
> Priority: Minor
> Labels: lhf
> Fix For: 2.0.8
>
>
> I was investigating slow responses for queries like {{select * from
> system.peers}} and noticed that the dynamic endpoint snitch was reporting
> that the query was _not_ worth merging. In this case, the local host had a
> score of 0, so {{return maxMerged < maxL1 + maxL2}} was returning false. I
> believe using a {{<=}} condition is the proper fix there.
> Additionally, because scores are looked up three separate times, this method
> is a prone to race conditions. I don't think it's worth fixing the race
> condition for a multi-node scenario, but at least in the single-node case, we
> can immediately return true and avoid any race conditions that would cause it
> to erroneously return false.
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