High_Group indexes have advantages and disadvantages.
Advantages | Disadvantages |
---|---|
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. |