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https://issues.apache.org/jira/browse/CASSANDRA-6109?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13805387#comment-13805387
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Tyler Hobbs commented on CASSANDRA-6109:
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bq. When they make up more than X% do we stop discriminating or merge them only
with other cold sstables?
I was thinking we would stop discriminating. The logic would basically be this:
{noformat}
total_reads = sum(sstable.reads_per_sec for sstable in sstables)
total_cold_reads = 0
cold_sstables = set()
for sstable in sorted(sstables, key=lambda sstable:
sstable.reads_per_key_per_sec):
if (sstable.reads_per_sec + total_cold_reads) / total_reads <
configurable_threshold:
cold_sstables.add(sstable)
total_cold_reads += sstable.reads_per_sec
else:
break
getBuckets(sstable for sstable in sstables if sstable not in cold_sstables)
{noformat}
> 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
>
> Attachments: 6109-v1.patch, 6109-v2.patch
>
>
> 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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