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Posted to commits@cassandra.apache.org by "Marcus Eriksson (JIRA)" <ji...@apache.org> on 2016/02/02 10:34:39 UTC
[jira] [Created] (CASSANDRA-11106) Experiment with strategies for
picking compaction candidates in LCS
Marcus Eriksson created CASSANDRA-11106:
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Summary: Experiment with strategies for picking compaction candidates in LCS
Key: CASSANDRA-11106
URL: https://issues.apache.org/jira/browse/CASSANDRA-11106
Project: Cassandra
Issue Type: Improvement
Reporter: Marcus Eriksson
Ideas taken here: http://rocksdb.org/blog/2921/compaction_pri/
Current strategy in LCS is that we keep track of the token that was last compacted and then we start a compaction with the sstable containing the next token (kOldestSmallestSeqFirst in the blog post above)
The rocksdb blog post above introduces a few ideas how this could be improved:
* pick the 'coldest' sstable (sstable with the oldest max timestamp) - we want to keep the hot data (recently updated) in the lower levels to avoid write amplification
* pick the sstable with the highest tombstone ratio, we want to get tombstones to the top level as quickly as possible.
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