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https://issues.apache.org/jira/browse/CASSANDRA-3668?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13194562#comment-13194562
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Peter Schuller commented on CASSANDRA-3668:
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Ok. Definitely interesting to look into then, because just the fact that we're
copying some arrays around is not adequate explanation for how we would
bottleneck to the point of only reaching 7 MB/second (that's *nothing*). The
indexes/bloom filters sound more plausible, but my understanding was that
Manish never observed CPU saturation.
Anyways, I was asking since I was assigned to review the patch. I'll try to do
a comparison of my own and see what I can find out.
*Possibly* relatedly I have observed cases where there is clearly something
wrong with the way we do I/O. Index sampling on start-up have been observed at
20% CPU utilization with plenty of I/O capacity to spare (this is on 0.8
though). In this case something is clearly outright wrong, and is not about
performance bottlenecks as such. It's possible something similar is going on
here, which would be very interesting to confirm/deny.
> Performance of sstableloader is affected in 1.0.x
> -------------------------------------------------
>
> Key: CASSANDRA-3668
> URL: https://issues.apache.org/jira/browse/CASSANDRA-3668
> Project: Cassandra
> Issue Type: Bug
> Components: API
> Affects Versions: 1.0.0
> Reporter: Manish Zope
> Assignee: Yuki Morishita
> Priority: Minor
> Labels: streaming
> Fix For: 1.1
>
> Attachments: 0001-Allow-multiple-connection-in-StreamInSession.patch,
> 0002-Allow-concurrent-stream-in-StreamOutSession.patch,
> 0003-Add-threads-option-to-sstableloader.patch,
> 3688-reply_before_closing_writer.txt, sstable-loader performance.txt
>
> Original Estimate: 48h
> Remaining Estimate: 48h
>
> One of my colleague had reported the bug regarding the degraded performance
> of the sstable generator and sstable loader.
> ISSUE :- https://issues.apache.org/jira/browse/CASSANDRA-3589
> As stated in above issue generator performance is rectified but performance
> of the sstableloader is still an issue.
> 3589 is marked as duplicate of 3618.Both issues shows resolved status.But the
> problem with sstableloader still exists.
> So opening other issue so that sstbleloader problem should not go unnoticed.
> FYI : We have tested the generator part with the patch given in 3589.Its
> Working fine.
> Please let us know if you guys require further inputs from our side.
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