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https://issues.apache.org/jira/browse/CASSANDRA-10979?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15094350#comment-15094350
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Jeff Ferland commented on CASSANDRA-10979:
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The problem I've got and why I considered it a bug is that the behavior as it
is right now doesn't appear to be as it was intended, and particularly negative
for me is that it destroys performance of my cluster by an order of magnitude
with LCS tables during a repair as potentially thousands of tables build up in
L0.
> LCS doesn't do L0 STC on new tables while an L0->L1 compaction is in progress
> -----------------------------------------------------------------------------
>
> Key: CASSANDRA-10979
> URL: https://issues.apache.org/jira/browse/CASSANDRA-10979
> Project: Cassandra
> Issue Type: Bug
> Components: Compaction
> Environment: 2.1.11 / 4.8.3 DSE.
> Reporter: Jeff Ferland
> Assignee: Carl Yeksigian
> Labels: compaction, leveled
> Fix For: 3.x
>
> Attachments: 10979-2.1.txt
>
>
> Reading code from
> https://github.com/apache/cassandra/blob/cassandra-2.1/src/java/org/apache/cassandra/db/compaction/LeveledManifest.java
> and comparing with behavior shown in
> https://gist.github.com/autocracy/c95aca6b00e42215daaf, the following happens:
> Score for L1,L2,and L3 is all < 1 (paste shows 20/10 and 200/100, due to
> incremental repair).
> Relevant code from here is
> if (Sets.intersection(l1overlapping, compacting).size() > 0)
> return Collections.emptyList();
> Since there will be overlap between what is compacting and L1 (in my case,
> pushing over 1,000 tables in to L1 from L0 SCTS), I get a pile up of 1,000
> smaller tables in L0 while awaiting the transition from L0 to L1 and destroy
> my performance.
> Requested outcome is to continue to perform SCTS on non-compacting L0 tables.
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