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https://issues.apache.org/jira/browse/CASSANDRA-7404?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jason Brown updated CASSANDRA-7404:
-----------------------------------
Description:
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.
was: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.
> 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: Jason Brown
> Labels: performance
> Fix For: 3.0
>
>
> 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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