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https://issues.apache.org/jira/browse/MAPREDUCE-4882?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13563472#comment-13563472
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Hadoop QA commented on MAPREDUCE-4882:
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{color:green}+1 overall{color}. Here are the results of testing the latest
attachment
http://issues.apache.org/jira/secure/attachment/12566626/MAPREDUCE-4882.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 1 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}. 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-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient.
{color:green}+1 contrib tests{color}. The patch passed contrib unit tests.
Test results:
https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/3281//testReport/
Console output:
https://builds.apache.org/job/PreCommit-MAPREDUCE-Build/3281//console
This message is automatically generated.
> Error in estimating the length of the output file in Spill Phase
> ----------------------------------------------------------------
>
> Key: MAPREDUCE-4882
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-4882
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Affects Versions: 0.20.2, 1.0.3
> Environment: Any Environment
> Reporter: Lijie Xu
> Assignee: Jerry Chen
> Labels: patch
> Attachments: MAPREDUCE-4882.patch
>
> Original Estimate: 1h
> Remaining Estimate: 1h
>
> The sortAndSpill() method in MapTask.java has an error in estimating the
> length of the output file.
> The "long size" should be "(bufvoid - bufstart) + bufend" not "(bufvoid -
> bufend) + bufstart" when "bufend < bufstart".
> Here is the original code in MapTask.java.
> private void sortAndSpill() throws IOException, ClassNotFoundException,
> InterruptedException {
> //approximate the length of the output file to be the length of the
> //buffer + header lengths for the partitions
> long size = (bufend >= bufstart
> ? bufend - bufstart
> : (bufvoid - bufend) + bufstart) +
> partitions * APPROX_HEADER_LENGTH;
> FSDataOutputStream out = null;
> ------------------------------------------------------------------------------
> I had a test on "TeraSort". A snippet from mapper's log is as follows:
> MapTask: Spilling map output: record full = true
> MapTask: bufstart = 157286200; bufend = 10485460; bufvoid = 199229440
> MapTask: kvstart = 262142; kvend = 131069; length = 655360
> MapTask: Finished spill 3
> In this occasioin, Spill Bytes should be (199229440 - 157286200) + 10485460 =
> 52428700 (52 MB) because the number of spilled records is 524287 and each
> record costs 100B.
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