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https://issues.apache.org/jira/browse/HADOOP-12107?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14597146#comment-14597146
]
Hadoop QA commented on HADOOP-12107:
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| (x) *{color:red}-1 overall{color}* |
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|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | pre-patch | 16m 19s | Pre-patch trunk compilation is
healthy. |
| {color:green}+1{color} | @author | 0m 0s | The patch does not contain any
@author tags. |
| {color:green}+1{color} | tests included | 0m 0s | The patch appears to
include 1 new or modified test files. |
| {color:green}+1{color} | javac | 7m 28s | There were no new javac warning
messages. |
| {color:green}+1{color} | javadoc | 9m 35s | There were no new javadoc
warning messages. |
| {color:green}+1{color} | release audit | 0m 22s | The applied patch does
not increase the total number of release audit warnings. |
| {color:red}-1{color} | checkstyle | 1m 5s | The applied patch generated 1
new checkstyle issues (total was 142, now 141). |
| {color:green}+1{color} | whitespace | 0m 1s | The patch has no lines that
end in whitespace. |
| {color:green}+1{color} | install | 1m 35s | mvn install still works. |
| {color:green}+1{color} | eclipse:eclipse | 0m 33s | The patch built with
eclipse:eclipse. |
| {color:green}+1{color} | findbugs | 1m 50s | The patch does not introduce
any new Findbugs (version 3.0.0) warnings. |
| {color:green}+1{color} | common tests | 21m 48s | Tests passed in
hadoop-common. |
| | | 60m 40s | |
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|| Subsystem || Report/Notes ||
| Patch URL |
http://issues.apache.org/jira/secure/attachment/12741209/HADOOP-12107.003.patch
|
| Optional Tests | javadoc javac unit findbugs checkstyle |
| git revision | trunk / 99271b7 |
| checkstyle |
https://builds.apache.org/job/PreCommit-HADOOP-Build/7020/artifact/patchprocess/diffcheckstylehadoop-common.txt
|
| hadoop-common test log |
https://builds.apache.org/job/PreCommit-HADOOP-Build/7020/artifact/patchprocess/testrun_hadoop-common.txt
|
| Test Results |
https://builds.apache.org/job/PreCommit-HADOOP-Build/7020/testReport/ |
| Java | 1.7.0_55 |
| uname | Linux asf906.gq1.ygridcore.net 3.13.0-36-lowlatency #63-Ubuntu SMP
PREEMPT Wed Sep 3 21:56:12 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux |
| Console output |
https://builds.apache.org/job/PreCommit-HADOOP-Build/7020/console |
This message was automatically generated.
> long running apps may have a huge number of StatisticsData instances under
> FileSystem
> -------------------------------------------------------------------------------------
>
> Key: HADOOP-12107
> URL: https://issues.apache.org/jira/browse/HADOOP-12107
> Project: Hadoop Common
> Issue Type: Bug
> Components: fs
> Affects Versions: 2.7.0
> Reporter: Sangjin Lee
> Assignee: Sangjin Lee
> Priority: Minor
> Attachments: HADOOP-12107.001.patch, HADOOP-12107.002.patch,
> HADOOP-12107.003.patch
>
>
> We observed with some of our apps (non-mapreduce apps that use filesystems)
> that they end up accumulating a huge memory footprint coming from
> {{FileSystem$Statistics$StatisticsData}} (in the {{allData}} list of
> {{Statistics}}).
> Although the thread reference from {{StatisticsData}} is a weak reference,
> and thus can get cleared once a thread goes away, the actual
> {{StatisticsData}} instances in the list won't get cleared until any of these
> following methods is called on {{Statistics}}:
> - {{getBytesRead()}}
> - {{getBytesWritten()}}
> - {{getReadOps()}}
> - {{getLargeReadOps()}}
> - {{getWriteOps()}}
> - {{toString()}}
> It is quite possible to have an application that interacts with a filesystem
> but does not call any of these methods on the {{Statistics}}. If such an
> application runs for a long time and has a large amount of thread churn, the
> memory footprint will grow significantly.
> The current workaround is either to limit the thread churn or to invoke these
> operations occasionally to pare down the memory. However, this is still a
> deficiency with {{FileSystem$Statistics}} itself in that the memory is
> controlled only as a side effect of those operations.
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