请你能帮我理解什么是512mb（黑体高亮）在Hive的上下文？它的内存大小是多少？我已经准备好了 export HADOOP_HEAPSIZE=4192 在我的 hive-site.xml 文件 hadoop@master:~/hive/conf$ ps -ef | grep 'hive' hadoop 5587 14年2月10日？00:05:27/usr/lib/jvm/default jdk/bin/java-xmx4192m-djava.net.preferipv4stack=true-dhadoop.log.dir=/home/hadoop/hadoop-2.7.3/logs-dhadoop.log.file=hadoop.log-dhadoop.home.dir=/home/hadoop/hadoop-2.7.3-dhadoop.id.str=hadoop-dhadoop.root.logger=info，console-djava.library.path=/home/hadoop/hadoop-2.7.3/lib/native-dhadoop.policy.file=hadoop-policy.xml-djava.net.preferipv4stack=true-xmx512m-dhadoop.security.logger=info，nullappender org.apache.hadoop.util.runjar/home/hadoop/hive/lib/hive-metastore-2.3.2.jar org.apache.hadoop.hive.metastore.hivemetastore
hadoop 9903 8034 0 10:54分/0 00:00:00 grep--color=auto-hive
hadoop 2164615918 1 07:37 pts/3 00:03:02/usr/lib/jvm/default jdk/bin/java-xmx4192m-djava.net.preferipv4stack=true-dhadoop.log.dir=/home/hadoop/hadoop-2.7.3/logs-dhadoop.log.file=hadoop.log-dhadoop.home.dir=/home/hadoop/hadoop-2.7.3-dhadoop.id.str=hadoop-dhadoop.root.logger=info，console-djava.library.path=/home/hadoop/hadoop-2.7.3/lib/native-dhadoop.policy.file=hadoop-policy.xml-djava.net.preferipv4stack=true-xmx512m-dproc\u hivecli-dlog4j.configurationfile=hive-log4j2.properties-djava.util.logging.config.file=/home/hadoop/hive/conf/parquet-logging.properties-dhadoop.security.logger=info，nullappender org.apache.hadoop.util.runjar/home/hadoop/hive/lib/hive-cli-2.3.2.jar org.apache.hadoop.hive.cli.clidriver