The High_Non_Group index type may be
appropriate for a Low_Fast column.
Note: It is almost always best to use an LF index if the number of unique values is low (less than
1,000). Consider this index first, if the column appears in the WHERE clause. Consider other index types
(HG and HNG) only when the number of unique values is high. For
range queries with a high number of unique values, also consider having an
HNG index.