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https://issues.apache.org/jira/browse/CASSANDRA-4897?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13537772#comment-13537772
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Sylvain Lebresne commented on CASSANDRA-4897:
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bq. There needs to be some kind of heuristics when to compact bucket with max
sized tables
In a way I agree, but that's pretty much what leveled compaction is. I'm of the
opinion that it might be better to spend time optimizing leveled compaction
rather than spending time trying to hack size tiered to do things it wasn't
designed for and that kind of go against its nature.
bq. If oldest table is older then user configured number of hours, then run
compaction
It'll kind of work, but it's a hack imho that has a number of downside in
practice. The main goal of compaction is to keep the number of compaction you
need to look at for a read low at all time. But by configuring a time between
which sstables are compacted, you don't control very well how much sstable may
accumulate during that time. Meaning that this setting will be hard to tune
right for users downright to impossible to tune correctly if your write load
varies too much over time. And on the other side, if you set that setting too
low, you will compact sstables regularly even when they don't need to be.
Don't get me wrong, I buy that for certain workload and for certain value of
maxSSTableSize and 'configured number of hours between compaction', you could
get something reasonably useful. But we also have to consider the risk of foot
shooting for users, and I'm not yet bought on the fact that it's acceptable in
that case.
> Allow tiered compaction define max sstable size
> -----------------------------------------------
>
> Key: CASSANDRA-4897
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4897
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Radim Kolar
> Assignee: Radim Kolar
> Fix For: 1.2.1
>
> Attachments: cass-maxsize1.txt, cass-maxsize2.txt
>
>
> Lucene is doing same thing. Correctly configured max segment size will
> recycle old data faster with less diskspace.
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