Local secondary index: Same partition key as primary key (diff. sort key)

Example:

Attributes: CustomerId (partition key) + OrderId (sort key), OrderCreationDt, ProductDetails, OrderStatus

LSI: [CustomerId (partition key) + OrderCreationDt] OR [CustomerId (partition key) + OrderStatus]

Defined at table creation (Modifications NOT allowed)

Global secondary index: Partition and sort key CAN be diff. from primary key

Example:

Attributes: storeCode (Primary Key), city, state, country, address

GSI: state or city or country

Can be added, modified & removed later

Stored separately (Separate RCU and WCU) from the main table

(Recommended) Project fewer attributes to save cost

(Recommended) Avoid throttling on main table - Assign RCU and WCU at least equal to main

table