Anuj created CASSANDRA-9146:
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Summary: Ever Growing Secondary Index 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
Priority: Blocker
Cluster has reached a state where every "repair -pr" operation on CF results in
numerous tiny sstables being flushed to disk. Most sstables are related to
secondary indexes. 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 secondary index tables are flushed during repair ? What is
triggering frequent/premature flush of secondary index 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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