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https://issues.apache.org/jira/browse/HDFS-7964?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15627893#comment-15627893
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Hadoop QA commented on HDFS-7964:
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| (x) *{color:red}-1 overall{color}* |
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|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue}  0m  
0s{color} | {color:blue} Docker mode activated. {color} |
| {color:red}-1{color} | {color:red} patch {color} | {color:red}  0m  6s{color} 
| {color:red} HDFS-7964 does not apply to branch-2.8. Rebase required? Wrong 
Branch? See https://wiki.apache.org/hadoop/HowToContribute for help. {color} |
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|| Subsystem || Report/Notes ||
| JIRA Issue | HDFS-7964 |
| JIRA Patch URL | 
https://issues.apache.org/jira/secure/attachment/12836221/HDFS-7964-branch-2.8.0.patch
 |
| Console output | 
https://builds.apache.org/job/PreCommit-HDFS-Build/17376/console |
| Powered by | Apache Yetus 0.4.0-SNAPSHOT   http://yetus.apache.org |


This message was automatically generated.



> Add support for async edit logging
> ----------------------------------
>
>                 Key: HDFS-7964
>                 URL: https://issues.apache.org/jira/browse/HDFS-7964
>             Project: Hadoop HDFS
>          Issue Type: Sub-task
>          Components: namenode
>    Affects Versions: 2.0.2-alpha
>            Reporter: Daryn Sharp
>            Assignee: Daryn Sharp
>             Fix For: 2.8.0, 2.9.0, 3.0.0-alpha1
>
>         Attachments: HDFS-7964-branch-2.8.0.patch, HDFS-7964-rebase.patch, 
> HDFS-7964.patch, HDFS-7964.patch, HDFS-7964.patch, HDFS-7964.patch
>
>
> Edit logging is a major source of contention within the NN.  LogEdit is 
> called within the namespace write log, while logSync is called outside of the 
> lock to allow greater concurrency.  The handler thread remains busy until 
> logSync returns to provide the client with a durability guarantee for the 
> response.
> Write heavy RPC load and/or slow IO causes handlers to stall in logSync.  
> Although the write lock is not held, readers are limited/starved and the call 
> queue fills.  Combining an edit log thread with postponed RPC responses from 
> HADOOP-10300 will provide the same durability guarantee but immediately free 
> up the handlers.



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