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Posted to common-issues@hadoop.apache.org by "Hadoop QA (JIRA)" <ji...@apache.org> on 2016/11/08 00:01:59 UTC
[jira] [Commented] (HADOOP-13804) MutableStat mean loses accuracy
if add(long, long) is used
[ https://issues.apache.org/jira/browse/HADOOP-13804?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15645872#comment-15645872 ]
Hadoop QA commented on HADOOP-13804:
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|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue} 0m 19s{color} | {color:blue} Docker mode activated. {color} |
| {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m 0s{color} | {color:green} The patch does not contain any @author tags. {color} |
| {color:green}+1{color} | {color:green} test4tests {color} | {color:green} 0m 0s{color} | {color:green} The patch appears to include 1 new or modified test files. {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 8m 40s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 11m 48s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 0m 35s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m 5s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m 25s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 1m 29s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m 51s{color} | {color:green} trunk passed {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 0m 36s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 9m 57s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 9m 57s{color} | {color:green} the patch passed {color} |
| {color:orange}-0{color} | {color:orange} checkstyle {color} | {color:orange} 0m 31s{color} | {color:orange} hadoop-common-project/hadoop-common: The patch generated 2 new + 29 unchanged - 2 fixed = 31 total (was 31) {color} |
| {color:green}+1{color} | {color:green} mvnsite {color} | {color:green} 1m 4s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} mvneclipse {color} | {color:green} 0m 22s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m 0s{color} | {color:green} The patch has no whitespace issues. {color} |
| {color:green}+1{color} | {color:green} findbugs {color} | {color:green} 1m 49s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m 54s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} unit {color} | {color:green} 8m 31s{color} | {color:green} hadoop-common in the patch passed. {color} |
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m 42s{color} | {color:green} The patch does not generate ASF License warnings. {color} |
| {color:black}{color} | {color:black} {color} | {color:black} 51m 53s{color} | {color:black} {color} |
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|| Subsystem || Report/Notes ||
| Docker | Image:yetus/hadoop:e809691 |
| JIRA Issue | HADOOP-13804 |
| JIRA Patch URL | https://issues.apache.org/jira/secure/attachment/12837858/HADOOP-13804.000.patch |
| Optional Tests | asflicense compile javac javadoc mvninstall mvnsite unit findbugs checkstyle |
| uname | Linux 9aa195bb39aa 3.13.0-93-generic #140-Ubuntu SMP Mon Jul 18 21:21:05 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux |
| Build tool | maven |
| Personality | /testptch/hadoop/patchprocess/precommit/personality/provided.sh |
| git revision | trunk / de3b4aa |
| Default Java | 1.8.0_111 |
| findbugs | v3.0.0 |
| checkstyle | https://builds.apache.org/job/PreCommit-HADOOP-Build/11016/artifact/patchprocess/diff-checkstyle-hadoop-common-project_hadoop-common.txt |
| Test Results | https://builds.apache.org/job/PreCommit-HADOOP-Build/11016/testReport/ |
| modules | C: hadoop-common-project/hadoop-common U: hadoop-common-project/hadoop-common |
| Console output | https://builds.apache.org/job/PreCommit-HADOOP-Build/11016/console |
| Powered by | Apache Yetus 0.4.0-SNAPSHOT http://yetus.apache.org |
This message was automatically generated.
> MutableStat mean loses accuracy if add(long, long) is used
> ----------------------------------------------------------
>
> Key: HADOOP-13804
> URL: https://issues.apache.org/jira/browse/HADOOP-13804
> Project: Hadoop Common
> Issue Type: Bug
> Components: metrics
> Affects Versions: 2.6.5
> Reporter: Erik Krogen
> Assignee: Erik Krogen
> Priority: Minor
> Attachments: HADOOP-13804.000.patch
>
>
> Currently if the {{MutableStat.add(long numSamples, long sum)}} method is used with a large sample count, the mean that is returned will be very inaccurate. This is a result of using the Welford method for variance calculation, which assumes that each sample is processed on its own, to calculate the mean as well. For variance this is fine, since variance numbers lose meaning if you add many samples at once, but the mean should still be accurate.
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