When the number of distinct values exceeds 16777216, no lookup table is created. Each flat style FP index contains an actual column cell value.
If MINIMIZE_STORAGE is ON, you can avoid the overhead of converting lookup FP entries into flat style. When the distinct row count for a particular field increases to more than 16777216, an FP(3) index is automatically converted to a flat style FP index. To create a flat FP, specify the IQ UNIQUE value to be greater than 16777216 at table creation time.
When you create a table with the DATE data type, a 2-byte FP index is created on the DATE field, which is independent of the settings in database option MINIMIZE_STORAGE.
To create a 3-byte FP or flat style FP index on the DATE field, use these values when creating the table:
For a 3-byte FP index— IQ UNIQUE value between 65537 and 16777216.
For a flat style FP index— IQ UNIQUE value greater than 16777216.