A Bitmap index is useful for improving queries on columns that have low cardinality.

Question

A Bitmap index is useful for improving queries on columns that have low cardinality.​

Quizplus · Accepted Answer

Bitmap indexes are most effective when used for columns with low cardinality, meaning a small number of distinct values compared to the size of the table. This is because bitmap indexes store the existence or non-existence of data as bits in a bitmap rather than individual rows, making them efficient for range and concatenation operations on columns with low cardinality.

A Bitmap Index Is Useful for Improving Queries on Columns