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https://issues.apache.org/jira/browse/HDFS-5010?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13713230#comment-13713230
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Hadoop QA commented on HDFS-5010:
---------------------------------
{color:red}-1 overall{color}. Here are the results of testing the latest
attachment
http://issues.apache.org/jira/secure/attachment/12593091/HDFS-5010.patch
against trunk revision .
{color:green}+1 @author{color}. The patch does not contain any @author
tags.
{color:red}-1 tests included{color}. The patch doesn't appear to include
any new or modified tests.
Please justify why no new tests are needed for this
patch.
Also please list what manual steps were performed to
verify this patch.
{color:green}+1 javac{color}. The applied patch does not increase the
total number of javac compiler warnings.
{color:green}+1 javadoc{color}. The javadoc tool did not generate any
warning messages.
{color:green}+1 eclipse:eclipse{color}. The patch built with
eclipse:eclipse.
{color:green}+1 findbugs{color}. The patch does not introduce any new
Findbugs (version 1.3.9) warnings.
{color:green}+1 release audit{color}. The applied patch does not increase
the total number of release audit warnings.
{color:green}+1 core tests{color}. The patch passed unit tests in
hadoop-hdfs-project/hadoop-hdfs.
{color:green}+1 contrib tests{color}. The patch passed contrib unit tests.
Test results:
https://builds.apache.org/job/PreCommit-HDFS-Build/4687//testReport/
Console output: https://builds.apache.org/job/PreCommit-HDFS-Build/4687//console
This message is automatically generated.
> Reduce the frequency of getCurrentUser() calls from namenode
> ------------------------------------------------------------
>
> Key: HDFS-5010
> URL: https://issues.apache.org/jira/browse/HDFS-5010
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: namenode, performance
> Affects Versions: 2.1.0-beta, 0.23.9
> Reporter: Kihwal Lee
> Assignee: Kihwal Lee
> Attachments: HDFS-5010.patch
>
>
> According to the "worst" jstack of a busy namenode I took, there were 29
> BLOCKED handler threads. All of them were blocked on the UGI class lock. Here
> is the breakdown:
> - 2 ensureInitialized() - from non static synchronized methods. This Jira
> will unblock these.
> - 27 getCurrentUser()
> Among the 27 threads that were blocked at getCurrentUser(),
> - 18 FSPermissionChecker() - from FSNamesystem#getPermissionChecker() in most
> namenode RPC methods
> - 8 BlockTokenSecretManager#generateToken() - getBlockLocations()
> - 1 NameNodeRpcServer.mkdirs
> I think FSPermissionChecker can be modified to be created with a passed in
> UGI. FSNamesystem can the one already stored in RPC server by calling
> getRemoteUser(). This will eliminate a bulk of getCurrentUser() calls from
> namenode RPC handlers. A similar change can be made to mkdirs. Block token
> generation is not as straightforward. Even without it we can eliminate
> majority of the calls.
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