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https://issues.apache.org/jira/browse/CASSANDRA-7404?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14606758#comment-14606758
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Ariel Weisberg commented on CASSANDRA-7404:
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The patch will need to be rebased to be usable again. I can spend some time on
that. The real blocker is finding a way to demonstrate that this actually
helps. I can help with rebasing if there is interest in making this happen.
> Use direct i/o for sequential operations (compaction/streaming)
> ---------------------------------------------------------------
>
> Key: CASSANDRA-7404
> URL: https://issues.apache.org/jira/browse/CASSANDRA-7404
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Jason Brown
> Assignee: Ariel Weisberg
> Labels: performance
> Fix For: 3.x
>
>
> Investigate using linux's direct i/o for operations where we read
> sequentially through a file (repair and bootstrap streaming, compaction
> reads, and so on). Direct i/o does not go through the kernel page page, so it
> should leave the hot cache pages used for live reads unaffected.
> Note: by using direct i/o, we will probably take a performance hit on reading
> the file we're sequentially scanning through (that is, compactions may get
> slower), but the goal of this ticket is to limit the impact of these
> background tasks on the main read/write functionality. Of course, I'll
> measure any perf hit that is incurred, and see if there's any mechanisms to
> mitigate it.
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