hiveserver2 发生gc以后导致远程jdbc连接hive会连接超时，解决办法
在hive-env.sh中修改HS2Heapsize的大小
在hive/bin/hive脚本里修改

# to initialize logging for all services
# export HADOOP_CLIENT_OPTS="$HADOOP_CLIENT_OPTS -Dlog4j.configurationFile=hive-log4j2.properties "

if [ x$SERVICE == x"metastore" ]; then
  export HADOOP_CLIENT_OPTS="$HADOOP_CLIENT_OPTS -Dlog4j.configurationFile=hive-metastore-log4j2.properties "
  
  #新加内容
elif [ x$SERVICE == x"hiveserver2" ]; then
  export HADOOP_CLIENT_OPTS="$HADOOP_CLIENT_OPTS -Xms12g  -Dlog4j.configurationFile=hive-log4j2.properties "
  
else
 export HADOOP_CLIENT_OPTS="$HADOOP_CLIENT_OPTS   -Dlog4j.configurationFile=hive-log4j2.properties "
fi

然后再重启hiveserver2