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From "Benedict (JIRA)" <j...@apache.org>
Subject [jira] [Created] (CASSANDRA-8920) Remove IntervalTree from maxPurgeableTimestamp calculation
Date Thu, 05 Mar 2015 13:49:38 GMT
Benedict created CASSANDRA-8920:
-----------------------------------

             Summary: Remove IntervalTree from maxPurgeableTimestamp calculation
                 Key: CASSANDRA-8920
                 URL: https://issues.apache.org/jira/browse/CASSANDRA-8920
             Project: Cassandra
          Issue Type: Improvement
          Components: Core
            Reporter: Benedict
            Priority: Minor


The IntervalTree only maps partition keys. Since a majority of users deploy a hashed partitioner
the work is mostly wasted, since they will be evenly distributed across the full token range
owned by the node - and in some cases it is a significant amount of work. We can perform a
corroboration against the file bounds if we get a BF match as a sanity check if we like, but
performing an IntervalTree search is significantly more expensive (esp. once murmur hash calculation
memoization goes mainstream).

In LCS, the keys are bounded, to it might appear that it would help, but in this scenario
we only compact against like bounds, so again it is not helpful.

With a ByteOrderedPartitioner it could potentially be of use, but this is sufficiently rare
to not optimise for IMO.



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