public Object clone() throws CloneNotSupportedException {
ColumnStat stat = (ColumnStat) super.clone();
initFromProto();
stat.column = (Column) this.column.clone();
stat.numDistVals = numDistVals;
stat.numNulls = numNulls;
stat.minValue = minValue;
stat.maxValue = maxValue;
return stat;
}
