HBase Forum

/usr/lib/hbase/bin/hbase hardcoded to -Xmx1000m – why?

  • #39083
    David Nguyen
    Member

    I have installed HDP via rpms on Centos6.4

    hbase-0.94.6.1.3.2.0-111.el5.noarch

    I was looking around to try and figure out where the -Xmx1000m is coming from as I see -Xmx defined twice when I run `ps -ef | grep master`. (output looks like this: /usr/java/default/bin/java -XX:OnOutOfMemoryError=kill -9 %p -Xmx1000m … -Xmx10g) and it turns out this is hardcoded in /usr/lib/hbase/bin/hbase

    line 107
    JAVA_HEAP_MAX=-Xmx1000m

    line 352-356
    # Exec unless HBASE_NOEXEC is set.
    if [ “${HBASE_NOEXEC}” != “” ]; then
    “$JAVA” -XX:OnOutOfMemoryError=”kill -9 %p” $JAVA_HEAP_MAX $HBASE_OPTS -classpath “$CLASSPATH” $CLASS “$@”
    else
    exec “$JAVA” -XX:OnOutOfMemoryError=”kill -9 %p” $JAVA_HEAP_MAX $HBASE_OPTS -classpath “$CLASSPATH” $CLASS “$@”
    fi

    So regardless of what is being set in hbase-env.sh, $JAVA_HEAP_MAX (which is defined at the top of the hbase script) is always getting pre–pended before $HBASE_OPTS. Is this intended? Are we expected to create $HBASE_HOME/conf/hbase-env-$COMMAND.sh and overload JAVA_HEAP_MAX if we want to use a different heap size than 1000m?

    David

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    Replies
  • #39357
    abdelrahman
    Moderator

    Hi David,

    the configuration setting has the default value and it can be changed. Here is how to change the Heap size for HBase Master and RegionServer processes? in hbase-env.sh file change the following parameters:

    export HBASE_MASTER_OPTS=”-Xmx1024m”
    export HBASE_REGIONSERVER_OPTS=”-server -XX:ParallelGCThreads=4 -Xmn{somevalue}m -XX:CMSInitiatingOccupancyFraction=70 -verbose:gc -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintGCDateStamps -Xloggc:/var/log/hbase/gc.log-`date +’%Y%m%d%H%M’` -Xms{somevalue}m -Xmx{somevalue}m -XX:ErrorFile=/var/log/hbase/hs_err_pid%p.log”
    #

    Thanks
    -Rahman

    #39364
    David Nguyen
    Member

    export HBASE_MASTER_OPTS=”-Xmx10g -Xms10g -XX:NewRatio=8″

    Thanks for the reply. Yeah I have those set in hbase-env.sh and I can see that my options are active via ps:

    /usr/java/default/bin/java -XX:OnOutOfMemoryError=kill -9 %p -Xmx1000m -ea -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -Xmx10g -Xms10g -XX:NewRatio=8 -Dhbase.log.dir=/var/log/hadoop/hbase -D …..

    The problem is that /usr/lib/hbase/bin/hbase is hardcoded to start hbase like this:

    “$JAVA” -XX:OnOutOfMemoryError=”kill -9 %p” $JAVA_HEAP_MAX $HBASE_OPTS -classpath “$CLASSPATH” $CLASS “$@”

    So regardless of what I put into hbase-env.sh (which gets pulled in as $HBASE_OPTS), $JAVA_HEAP_MAX is prepended to the options.

    David

    #39365
    abdelrahman
    Moderator

    Hi David,

    Please confirm the HBase heap size process by using jmap -heap option. From command line, please run:

    jmap -F -heap PID | grep -i MaxHeapSize

    PID is the process id.

    Thanks
    -Rahman

    #39376
    David Nguyen
    Member

    Good idea to check it with jmap. Looks like I’ve been worrying about nothing

    $ /usr/java/default/bin/jmap -F -heap 37861 | grep -i maxheapsize
    Attaching to process ID 37861, please wait…
    Debugger attached successfully.
    Server compiler detected.
    JVM version is 20.6-b01
    MaxHeapSize = 10737418240 (10240.0MB)

    Thanks for the help!

    David

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