Advantages and Disadvantages of High_Group

Quickly processes queries with GROUP BY.

This index needs more disk space than the HNG index (it can take as much as three times more space than raw data).

This index type takes the longest time to populate with data, and to delete.

You cannot use this index if data in your columns is BIT, VARBINARY > 255 bytes, CHAR > 255 bytes, or VARCHAR > 255 bytes.

This index is not recommended for FLOAT, REAL, and DOUBLE data.