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Jonathan Ellis commented on CASSANDRA-11035:
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The problem here was, you end up doing quadratic work comparing each sstable to
each other to find the best candidates to merge. So the question is, do we try
to come up with a clever way to avoid this? Or do we go ahead and brute force
it, which would require updating HyperLogLog to use off-heap registers? (The
latter actually looks pretty easy, now that I check the source.)
> Use cardinality estimation to pick better compaction candidates for STCS
> (SizeTieredCompactionStrategy)
> -------------------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-11035
> URL: https://issues.apache.org/jira/browse/CASSANDRA-11035
> Project: Cassandra
> Issue Type: Improvement
> Components: Compaction
> Reporter: Wei Deng
>
> This was initially mentioned in this blog post
> http://www.datastax.com/dev/blog/improving-compaction-in-cassandra-with-cardinality-estimation
> but I couldn't find any existing JIRA for it. As stated by [~jbellis],
> "Potentially even more useful would be using cardinality estimation to pick
> better compaction candidates. Instead of blindly merging sstables of a
> similar size a la SizeTieredCompactionStrategy." The L0 STCS in LCS should
> benefit as well.
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