hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Hadoop QA (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-12590) A solution for data skew in HBase-Mapreduce Job
Date Wed, 17 Dec 2014 12:24:39 GMT

    [ https://issues.apache.org/jira/browse/HBASE-12590?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14249751#comment-14249751
] 

Hadoop QA commented on HBASE-12590:
-----------------------------------

{color:red}-1 overall{color}.  Here are the results of testing the latest attachment 
  http://issues.apache.org/jira/secure/attachment/12687706/HBASE-12590-v4.patch
  against master branch at commit 99a11390b4758c211af04af2ca0696ac6e3e0aeb.
  ATTACHMENT ID: 12687706

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

    {color:green}+1 tests included{color}.  The patch appears to include 6 new or modified
tests.

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

    {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:red}-1 checkstyle{color}.  The applied patch generated 2086 checkstyle
errors (more than the master's current 2084 errors).

    {color:green}+1 findbugs{color}.  The patch does not introduce any new Findbugs (version
2.0.3) warnings.

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

    {color:green}+1 lineLengths{color}.  The patch does not introduce lines longer than 100

  {color:green}+1 site{color}.  The mvn site goal succeeds with this patch.

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

Test results: https://builds.apache.org/job/PreCommit-HBASE-Build/12107//testReport/
Findbugs warnings: https://builds.apache.org/job/PreCommit-HBASE-Build/12107//artifact/patchprocess/newPatchFindbugsWarningshbase-hadoop-compat.html
Findbugs warnings: https://builds.apache.org/job/PreCommit-HBASE-Build/12107//artifact/patchprocess/newPatchFindbugsWarningshbase-prefix-tree.html
Findbugs warnings: https://builds.apache.org/job/PreCommit-HBASE-Build/12107//artifact/patchprocess/newPatchFindbugsWarningshbase-examples.html
Findbugs warnings: https://builds.apache.org/job/PreCommit-HBASE-Build/12107//artifact/patchprocess/newPatchFindbugsWarningshbase-server.html
Findbugs warnings: https://builds.apache.org/job/PreCommit-HBASE-Build/12107//artifact/patchprocess/newPatchFindbugsWarningshbase-common.html
Findbugs warnings: https://builds.apache.org/job/PreCommit-HBASE-Build/12107//artifact/patchprocess/newPatchFindbugsWarningshbase-rest.html
Findbugs warnings: https://builds.apache.org/job/PreCommit-HBASE-Build/12107//artifact/patchprocess/newPatchFindbugsWarningshbase-protocol.html
Findbugs warnings: https://builds.apache.org/job/PreCommit-HBASE-Build/12107//artifact/patchprocess/newPatchFindbugsWarningshbase-client.html
Findbugs warnings: https://builds.apache.org/job/PreCommit-HBASE-Build/12107//artifact/patchprocess/newPatchFindbugsWarningshbase-thrift.html
Findbugs warnings: https://builds.apache.org/job/PreCommit-HBASE-Build/12107//artifact/patchprocess/newPatchFindbugsWarningshbase-hadoop2-compat.html
Findbugs warnings: https://builds.apache.org/job/PreCommit-HBASE-Build/12107//artifact/patchprocess/newPatchFindbugsWarningshbase-annotations.html
Checkstyle Errors: https://builds.apache.org/job/PreCommit-HBASE-Build/12107//artifact/patchprocess/checkstyle-aggregate.html

                Console output: https://builds.apache.org/job/PreCommit-HBASE-Build/12107//console

This message is automatically generated.

> A solution for data skew in HBase-Mapreduce Job
> -----------------------------------------------
>
>                 Key: HBASE-12590
>                 URL: https://issues.apache.org/jira/browse/HBASE-12590
>             Project: HBase
>          Issue Type: Improvement
>          Components: mapreduce
>            Reporter: Weichen Ye
>         Attachments: A Solution for Data Skew in HBase-MapReduce Job (Version2).pdf,
A Solution for Data Skew in HBase-MapReduce Job (Version3).pdf, HBASE-12590-v3.patch, HBASE-12590-v4.patch,
HBase-12590-v1.patch, HBase-12590-v2.patch
>
>
> 1, Motivation
> In production environment, data skew is a very common case. A HBase table may contains
a lot of small regions and several large regions. Small regions waste a lot of computing resources.
If we use a job to scan a table with 3000 small regions, we need a job with 3000 mappers.
Large regions always block the job. If in a 100-region table, one region is far large then
the other 99 regions. When we run a job with the table as input, 99 mappers will be completed
very quickly, and then we need to wait for the last mapper for a long time.
> 2, Configuration
> Add three new configuration 
> hbase.mapreduce.input.autobalance = true means enabling the “auto balance” in HBase-MapReduce
jobs. The default value is false. 
> hbase.mapreduce.input.autobalance.maxskewratio= 3 (default is 3). If a region size is
larger than 3x average region size, treat the region as “proportionately too large”.
> hbase.table.row.textkey  = true means the row key is text. False means binary row key.
It is used to find the mid row key in large region. The default value is true. 
> If (region size >= average size*ratio) :  cut the region into two MR input splits
> If (average size <= region size < average size*ratio) : one region as one MR input
split
> If (sum of several continuous regions size < average size): combine these regions
into one MR input split.
> Example:
> In attachment
> Welcome to the Review Board.
> https://reviews.apache.org/r/28494/diff/#



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message