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https://issues.apache.org/jira/browse/HDFS-13594?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16979750#comment-16979750
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Wei-Chiu Chuang commented on HDFS-13594:
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Is this still an issue after HDFS-14541 and HDFS-14535?
> the lock of ShortCircuitCache is hold while close the ShortCircuitReplica
> ---------------------------------------------------------------------------
>
> Key: HDFS-13594
> URL: https://issues.apache.org/jira/browse/HDFS-13594
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs-client
> Affects Versions: 3.0.2
> Reporter: Gang Xie
> Assignee: Lisheng Sun
> Priority: Minor
> Attachments: no_hdfs.svg
>
>
> When we are profiling SC read, we find that ShortCircuitCache's lock is a hot
> spot. After look into the code, we find that when close BlockReaderLocal, it
> tries to trimEvictionMaps, and several ShortCircuitReplicas are closed while
> the lock being hold. This slows down the close of the BlockReaderLocal, and
> the worse is that it blocks the other allocating of the new
> ShortCircuitReplicas.
> An idea to avoid this is to close the replica in an async way. I will do a
> prototype and get the performance.
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