The database commonly uses an index range scan to access selective data. The selectivity is the percentage of rows in the table that the query selects, with 0 meaning no rows and 1 meaning all rows. Selectivity is tied to a query predicate, such as WHERE last_name LIKE 'A%', or a combination of predicates.
Types of Distribution: Intensive, Selective and Exclusive Distribution. Some of the important types of distribution in international market are 1. Intensive 2. Selective and 3. Exclusive distribution.
The distribution style (EVEN, KEY, or ALL) defines how data for a table is spread across the cluster. A common distribution style for large tables is KEY. You specify one column in the table to be the KEY when you create the table. All of the rows with the same key value always go to the same node.