the default hive metastore jvm configuration according to https://github.com/apache/hive/blob/master/conf/hive-env.sh.template , is as the following

 if [ "$SERVICE" = "cli" ]; then
   if [ -z "$DEBUG" ]; then
     export HADOOP_OPTS="$HADOOP_OPTS -XX:NewRatio=12 -Xms10m -XX:MaxHeapFreeRatio=40 -XX:MinHeapFreeRatio=15 -XX:+UseParNewGC -XX:-UseGCOverheadLimit"
   else
     export HADOOP_OPTS="$HADOOP_OPTS -XX:NewRatio=12 -Xms10m -XX:MaxHeapFreeRatio=40 -XX:MinHeapFreeRatio=15 -XX:-UseGCOverheadLimit"
   fi
 fi

from my understand based on above syntax and in order to move to G1GC I add the -XX:+UseG1GC as the following:

if [ "$SERVICE" = "cli" ]; then
  if [ -z "$DEBUG" ]; then
     export HADOOP_OPTS="$HADOOP_OPTS -XX:+UseG1GC -XX:NewRatio=12 -Xms10m -XX:MaxHeapFreeRatio=40 -XX:MinHeapFreeRatio=15 -XX:+UseParNewGC -XX:-UseGCOverheadLimit"
  else
     export HADOOP_OPTS="$HADOOP_OPTS -XX:+UseG1GC -XX:NewRatio=12 -Xms10m -XX:MaxHeapFreeRatio=40 -XX:MinHeapFreeRatio=15 -XX:-UseGCOverheadLimit"
fi
fi

but I not sure if my setting is good enough and right to works with G1GC or maybe I am wrong?