[jira] [Commented] (HDFS-6268) Better sorting in NetworkTopology#pseudoSortByDistance when no local node is found

["Hadoop QA (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HDFS-6268?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13976531#comment-13976531 ] 

Hadoop QA commented on HDFS-6268:
---------------------------------

{color:red}-1 overall{color}.  Here are the results of testing the latest attachment 
  http://issues.apache.org/jira/secure/attachment/12641170/hdfs-6268-1.patch
  against trunk revision .

    {color:green}+1 @author{color}.  The patch does not contain any @author tags.

    {color:green}+1 tests included{color}.  The patch appears to include 2 new or modified test files.

    {color:green}+1 javac{color}.  The applied patch does not increase the total number of javac compiler warnings.

    {color:green}+1 javadoc{color}.  There were no new javadoc 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:red}-1 core tests{color}.  The patch failed these unit tests in hadoop-common-project/hadoop-common hadoop-hdfs-project/hadoop-hdfs:

                  org.apache.hadoop.hdfs.TestGetBlocks

    {color:green}+1 contrib tests{color}.  The patch passed contrib unit tests.

Test results: https://builds.apache.org/job/PreCommit-HDFS-Build/6689//testReport/
Console output: https://builds.apache.org/job/PreCommit-HDFS-Build/6689//console

This message is automatically generated.

> Better sorting in NetworkTopology#pseudoSortByDistance when no local node is found
> ----------------------------------------------------------------------------------
>
>                 Key: HDFS-6268
>                 URL: https://issues.apache.org/jira/browse/HDFS-6268
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>    Affects Versions: 2.4.0
>            Reporter: Andrew Wang
>            Assignee: Andrew Wang
>            Priority: Minor
>         Attachments: hdfs-6268-1.patch
>
>
> In NetworkTopology#pseudoSortByDistance, if no local node is found, it will always place the first rack local node in the list in front.
> This became an issue when a dataset was loaded from a single datanode. This datanode ended up being the first replica for all the blocks in the dataset. When running an Impala query, the non-local reads when reading past a block boundary were all hitting this node, meaning massive load skew.



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