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https://issues.apache.org/jira/browse/CASSANDRA-6109?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13785422#comment-13785422
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Tyler Hobbs commented on CASSANDRA-6109:
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There's a problem with prioritizing the compaction manager queue: for normal
compactions, we enqueue a task that will actually pick the sstables to compact
at the last moment, right before the task is run. I think we have three
options:
# Don't try to prioritize the compaction manager queue
# Pick the sstables upfront (maybe only for STCS and not LCS? This behavior was
added for CASSANDRA-4310, which is primarily concerned with LCS) and
potentially compact a less-than-optimal set of sstables
# Prioritize the task when it's submitted by picking an initial bucket of
sstables; finalize the bucket, adding sstables if necessary, just before the
task is executed
I would lean towards #3, although it's the most complex. I just wanted to hear
your thoughts before writing that up.
> Consider coldness in STCS compaction
> ------------------------------------
>
> Key: CASSANDRA-6109
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6109
> Project: Cassandra
> Issue Type: New Feature
> Components: Core
> Reporter: Jonathan Ellis
> Assignee: Tyler Hobbs
> Fix For: 2.0.2
>
>
> I see two options:
> # Don't compact cold sstables at all
> # Compact cold sstables only if there is nothing more important to compact
> The latter is better if you have cold data that may become hot again... but
> it's confusing if you have a workload such that you can't keep up with *all*
> compaction, but you can keep up with hot sstable. (Compaction backlog stat
> becomes useless since we fall increasingly behind.)
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