[CASSANDRA-13258] Rethink read-time defragmentation introduced in 1.1 (CASSANDRA-2503)

• Type: Improvement
• Status: Open
• Priority: Normal
• Resolution: Unresolved
• Component/s: Local/Compaction
• Assignee: Unassigned
• Reporter: Nate McCall
• Created: 23/Feb/17 01:07
• Updated: 16/Apr/19 09:30

Description

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.