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https://issues.apache.org/jira/browse/HDFS-11187?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16346967#comment-16346967
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Kihwal Lee commented on HDFS-11187:
-----------------------------------

bq.  Not sure why yetus said it failed tests.
Some tests failed to terminate normally, so surefire did not report any 
failures, but maven did. Look at the output.
 
[https://builds.apache.org/job/PreCommit-HDFS-Build/22888/artifact/out/patch-unit-hadoop-hdfs-project_hadoop-hdfs.txt]

> Optimize disk access for last partial chunk checksum of Finalized replica
> -------------------------------------------------------------------------
>
>                 Key: HDFS-11187
>                 URL: https://issues.apache.org/jira/browse/HDFS-11187
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: datanode
>            Reporter: Wei-Chiu Chuang
>            Assignee: Wei-Chiu Chuang
>            Priority: Major
>         Attachments: HDFS-11187.001.patch, HDFS-11187.002.patch, 
> HDFS-11187.003.patch, HDFS-11187.004.patch, HDFS-11187.005.patch
>
>
> The patch at HDFS-11160 ensures BlockSender reads the correct version of 
> metafile when there are concurrent writers.
> However, the implementation is not optimal, because it must always read the 
> last partial chunk checksum from disk while holding FsDatasetImpl lock for 
> every reader. It is possible to optimize this by keeping an up-to-date 
> version of last partial checksum in-memory and reduce disk access.
> I am separating the optimization into a new jira, because maintaining the 
> state of in-memory checksum requires a lot more work.



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