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https://issues.apache.org/jira/browse/CASSANDRA-9146?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14576373#comment-14576373
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Anuj Wadehra commented on CASSANDRA-9146:
-----------------------------------------
We have 24 cores and concurrent_compactors are 12. Does concurrent compactors
impact creation of tiny sstables during repair?
We haven't set cold_ reads_to_omit. Anyways making it 0 doesnt have any impact
in 2.0.3.
> Ever Growing sstables after every Repair
> ----------------------------------------
>
> Key: CASSANDRA-9146
> URL: https://issues.apache.org/jira/browse/CASSANDRA-9146
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Reporter: Anuj Wadehra
> Attachments: sstables.txt, system-modified.log
>
>
> Cluster has reached a state where every "repair -pr" operation on CF results
> in numerous tiny sstables being flushed to disk. Due to thousands of
> sstables, reads have started timing out. Even though compaction begins for
> one of the secondary index, sstable count after repair remains very high
> (thousands). Every repair adds thousands of sstables.
> Problems:
> 1. Why burst of tiny tables are flushed during repair ? What is triggering
> frequent/premature flush of sstable (more than hundred in every burst)? At
> max we see one ParNew GC pauses >200ms.
> 2. Why auto-compaction is not compacting all sstables. Is it related to
> coldness issue(CASSANDRA-8885) where compaction doesn't works even when
> cold_reads_to_omit=0 by default?
> If coldness is the issue, we are stuck in infinite loop: reads will
> trigger compaction but reads timeout as sstable count is in thousands
> 3. What's the way out if we face this issue in Prod?
> Is this issue fixed in latest production release 2.0.13? Issue looks similar
> to CASSANDRA-8641, but the issue is fixed in only 2.1.3. I think it should be
> fixed in 2.0 branch too.
> Configuration:
> Compaction Strategy: STCS
> memtable_flush_writers=4
> memtable_flush_queue_size=4
> in_memory_compaction_limit_in_mb=32
> concurrent_compactors=12
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