Add Java heap on Hadoop

Method 1. Modify /etc/hadoop/conf/hadoop-env.sh

export HADOOP_CLIENT_OPTS="-Xmx1024m $HADOOP_CLIENT_OPTS"

Method 2. Modify /etc/hadoop/conf/mapred-site.xml

<property>
<name>mapred.child.java.opts</name>
<value>-Xmx1024m</value>
</property>