DynamoDB allocates additional partitions to a table in the following situations:

If you increase the table's provisioned throughput settings beyond what the existing partitions can support.

If an existing partition fills to capacity and more storage space is required.

Partition management occurs automatically in the background and is transparent to your applications. Your table remains available throughout and fully supports your provisioned throughput requirements.

For more details, see Partition key design.

Global secondary indexes in DynamoDB are also composed of partitions. The data in a global secondary index is stored separately from the data in its base table, but index partitions behave in much the same way as table partitions