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https://issues.apache.org/jira/browse/CASSANDRA-12730?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15647361#comment-15647361
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Stefan Podkowinski commented on CASSANDRA-12730:
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In 2.x, sstables that have been streamed to a host would be added directly to
the set of existing sstables and thus by-pass the regular write path. However,
as you're using 3.x with MVs, it looks like this doesn't apply for your case
and all streamed sstables will be read and the content will go through the
regular write path in order to make sure that the MVs will be updated properly,
see {{StreamReceiveTask.OnCompletionRunnable}}.
That's interesting; I wasn't aware of this aspect of MVs until now. That means
indeed all streammed sstables for tables with MVs will be flushed and the
accumulated sstable switch count should match to the growing number of sstables.
> Thousands of empty SSTables created during repair - TMOF death
> --------------------------------------------------------------
>
> Key: CASSANDRA-12730
> URL: https://issues.apache.org/jira/browse/CASSANDRA-12730
> Project: Cassandra
> Issue Type: Bug
> Components: Local Write-Read Paths
> Reporter: Benjamin Roth
> Priority: Critical
>
> Last night I ran a repair on a keyspace with 7 tables and 4 MVs each
> containing a few hundret million records. After a few hours a node died
> because of "too many open files".
> Normally one would just raise the limit, but: We already set this to 100k.
> The problem was that the repair created roughly over 100k SSTables for a
> certain MV. The strange thing is that these SSTables had almost no data (like
> 53bytes, 90bytes, ...). Some of them (<5%) had a few 100 KB, very few (<1%
> had normal sizes like >= few MB). I could understand, that SSTables queue up
> as they are flushed and not compacted in time but then they should have at
> least a few MB (depending on config and avail mem), right?
> Of course then the node runs out of FDs and I guess it is not a good idea to
> raise the limit even higher as I expect that this would just create even more
> empty SSTables before dying at last.
> Only 1 CF (MV) was affected. All other CFs (also MVs) behave sanely. Empty
> SSTables have been created equally over time. 100-150 every minute. Among the
> empty SSTables there are also Tables that look normal like having few MBs.
> I didn't see any errors or exceptions in the logs until TMOF occured. Just
> tons of streams due to the repair (which I actually run over cs-reaper as
> subrange, full repairs).
> After having restarted that node (and no more repair running), the number of
> SSTables went down again as they are compacted away slowly.
> According to [~zznate] this issue may relate to CASSANDRA-10342 +
> CASSANDRA-8641
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