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https://issues.apache.org/jira/browse/CASSANDRA-5263?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14044165#comment-14044165
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sankalp kohli commented on CASSANDRA-5263:
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The calculations to calculate number of keys contains dupes and can be improved
by using cardinality i think.
Overlapping ratio = (total number of unique partitions in stables containing
the range using cardinality)/(total number of non unique partitions in these
stables)
> Increase merkle tree depth as needed
> ------------------------------------
>
> Key: CASSANDRA-5263
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5263
> Project: Cassandra
> Issue Type: Improvement
> Affects Versions: 1.1.9
> Reporter: Ahmed Bashir
> Assignee: Yuki Morishita
> Fix For: 2.1.1
>
> Attachments: 5263-2.1-v1.txt
>
>
> Currently, the maximum depth allowed for Merkle trees is hardcoded as 15.
> This value should be configurable, just like phi_convict_treshold and other
> properties.
> Given a cluster with nodes responsible for a large number of row keys, Merkle
> tree comparisons can result in a large amount of unnecessary row keys being
> streamed.
> Empirical testing indicates that reasonable changes to this depth (18, 20,
> etc) don't affect the Merkle tree generation and differencing timings all
> that much, and they can significantly reduce the amount of data being
> streamed during repair.
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