The global secondary indexes provide new ways to interact with our tables. GSIs can use alternate keys different from the PK. For example, a GSI can be used to listen to the most popular songs by genre. Navigate to the Indexes tab of the selected Music table and create an index as follows:

Note that the GSI has its own read capacity units (RCU) and write capacity units (WCU), these indexes act as a dependent table with the specified attributes projected automatically by the index. Once the index is in the Active state perform a Scan operation to see its contents. As you may note there are no items to show, this is because once the index is created Dynamo will start projecting new and updated data maintaining consistency between the Music table and the GSI.

Try adding some new records to the Music table and perform a query to the Genre-ListenCount-index: