[jira] [Created] (CASSANDRA-13258) Rethink read-time defragmentation introduced in 1.0 (CASSANDRA-2503)

["Nate McCall (JIRA)" <ji...@apache.org>]

Nate McCall created CASSANDRA-13258:
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             Summary: Rethink read-time defragmentation introduced in 1.0 (CASSANDRA-2503)
                 Key: CASSANDRA-13258
                 URL: https://issues.apache.org/jira/browse/CASSANDRA-13258
             Project: Cassandra
          Issue Type: Bug
            Reporter: Nate McCall


tl,dr; we issue a Mutation(!) on a read when using STCS and there are more than minCompactedThreshold SSTables encountered by the iterator. (See org/apache/cassandra/db/SinglePartitionReadCommand.java:782)

I can see a couple of use cases where this *might* be useful, but from a practical stand point, this is an excellent way to exacerbate compaction falling behind.

With the introduction of other, purpose built compaction strategies, I would be interested to hear why anyone would consider this still a good idea. Note that we only do it for STCS so at best, we are inconsistent. 

There are some interesting comments on CASSANDRA-10342 regarding this as well.



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