Column store index -min_data_id and max_data_idis null

Hi,

I have few column store in different table in DB. When I was analyzing the column store index  one  index have 12 segments ,When I looked into sys.column_store_segments for  all the 12 segments min_data_id and Max_data_id is "NULL".

In which scenarios these values become null? Will this cause a performance issue in queries?

Regards

Tom