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https://issues.apache.org/jira/browse/YARN-2996?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14267322#comment-14267322
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Zhijie Shen commented on YARN-2996:
-----------------------------------
My bad. I mean MemoryRMStateStore#updateRMDelegationTokenState. It contains two
other synchronized methods, but it's better to keep them atomic, and not
interpolated by other operations.
> Refine some fs operations in FileSystemRMStateStore to improve performance
> --------------------------------------------------------------------------
>
> Key: YARN-2996
> URL: https://issues.apache.org/jira/browse/YARN-2996
> Project: Hadoop YARN
> Issue Type: Improvement
> Components: resourcemanager
> Reporter: Yi Liu
> Assignee: Yi Liu
> Attachments: YARN-2996.001.patch, YARN-2996.002.patch
>
>
> In {{FileSystemRMStateStore}}, we can refine some fs operations to improve
> performance:
> *1.* There are several places invoke {{fs.exists}}, then
> {{fs.getFileStatus}}, we can merge them to save one RPC call
> {code}
> if (fs.exists(versionNodePath)) {
> FileStatus status = fs.getFileStatus(versionNodePath);
> {code}
> *2.*
> {code}
> protected void updateFile(Path outputPath, byte[] data) throws Exception {
> Path newPath = new Path(outputPath.getParent(), outputPath.getName() +
> ".new");
> // use writeFile to make sure .new file is created atomically
> writeFile(newPath, data);
> replaceFile(newPath, outputPath);
> }
> {code}
> The {{updateFile}} is not good too, it write file to _output\_file_.tmp, then
> rename to _output\_file_.new, then rename it to _output\_file_, we can reduce
> one rename operation.
> Also there is one unnecessary import, we can remove it.
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