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https://issues.apache.org/jira/browse/HADOOP-10245?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13877837#comment-13877837
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Wei Yan commented on HADOOP-10245:
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[~shanyu], as discussed, there are multiple places configuring -Xmx. In the
lastest patch in HADOOP-9870 provided by [~jhsenjaliya], $HADOOP_HEAPSIZE is
checked firstly; if not set, assign -Xmx512m. Additionally, in bin/hadoop, also
check the -Xmx configuration, to avoid duplicate configurations.
Simply remove -Xmx512m from HADOOP_CLIENT_OPTS may still generate multiple
-Xmx, as bin/hadoop also has a default $JAVA_HEAP_MAX, which is 1000m.
IMO, I think HADOOP-9870 has fixed this issue.
> Hadoop command line always appends "-Xmx" option twice
> ------------------------------------------------------
>
> Key: HADOOP-10245
> URL: https://issues.apache.org/jira/browse/HADOOP-10245
> Project: Hadoop Common
> Issue Type: Bug
> Components: bin
> Affects Versions: 2.2.0
> Reporter: shanyu zhao
> Assignee: shanyu zhao
> Attachments: HADOOP-10245.patch
>
>
> The Hadoop command line scripts (hadoop.sh or hadoop.cmd) will call java with
> "-Xmx" options twice. The impact is that any user defined HADOOP_HEAP_SIZE
> env variable will take no effect because it is overwritten by the second
> "-Xmx" option.
> For example, here is the java cmd generated for command "hadoop fs -ls /",
> Notice that there are two "-Xmx" options: "-Xmx1000m" and "-Xmx512m" in the
> command line:
> java -Xmx1000m -Dhadoop.log.dir=C:\tmp\logs -Dhadoop.log.file=hadoop.log
> -Dhadoop.root.logger=INFO,c
> onsole,DRFA -Xmx512m -Dhadoop.security.logger=INFO,RFAS -classpath XXX
> org.apache.hadoop.fs.FsShell -ls /
> Here is the root cause:
> The call flow is: hadoop.sh calls hadoop_config.sh, which in turn calls
> hadoop-env.sh.
> In hadoop.sh, the command line is generated by the following pseudo code:
> java $JAVA_HEAP_MAX $HADOOP_CLIENT_OPTS -classpath ...
> In hadoop-config.sh, $JAVA_HEAP_MAX is initialized as "-Xmx1000m" if user
> didn't set $HADOOP_HEAP_SIZE env variable.
> In hadoop-env.sh, $HADOOP_CLIENT_OPTS is set as this:
> export HADOOP_CLIENT_OPTS="-Xmx512m $HADOOP_CLIENT_OPTS"
> To fix this problem, we should remove the "-Xmx512m" from HADOOP_CLIENT_OPTS.
> If we really want to change the memory settings we need to use
> $HADOOP_HEAP_SIZE env variable.
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