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https://issues.apache.org/jira/browse/HDFS-16414?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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JiangHua Zhu resolved HDFS-16414.
---------------------------------
    Resolution: Not A Bug

> Improve asynchronous edit: reduce the time that edit waits to enter 
> editPendingQ
> --------------------------------------------------------------------------------
>
>                 Key: HDFS-16414
>                 URL: https://issues.apache.org/jira/browse/HDFS-16414
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: fs async, namenode
>    Affects Versions: 2.9.2
>            Reporter: JiangHua Zhu
>            Assignee: JiangHua Zhu
>            Priority: Major
>
> When dfs.namenode.edits.asynclogging=true, FSEditLogAsync starts to work, 
> which is very helpful for improving the speed of NameNode processing Call.
> But there is a strange phenomenon here. When a lot of calls enter the 
> NameNode through RPC within a period of time, the handler will be forced to 
> wait, in seconds:
> FSEditLogAsync#enqueueEdit():
> if (Thread.holdsLock(this)) {
>            int permits = overflowMutex.drainPermits();
>            try {
>              do {
>                this.wait(1000); // will be notified by next logSync.
>              } while (!editPendingQ.offer(edit));
>            } finally {
>              overflowMutex.release(permits);
>            }
>          }
> We should reduce this.wait(1000) here so that edit can be processed quickly.



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