Azure SQL Data Warehouse (SQL DW) is a new platform-as-a service (PaaS) that distributes workloads across multiple compute resources, called massively parallel processing (MPP). Loading data into a MPP data warehouse requires a different approach, or mindset, than traditional methods of loading data into a SMP data warehouse.
To help you with understanding how best to load data into SQL DW, Microsoft has released an excellent white paper by Martin Lee, John Hoang, and Joe Sack. It describes t the SQL DW architecture and explores several loading techniques to help you reach maximum data-loading throughput and identify the scenarios that best suit each of these techniques.
Check it out: Azure SQL Data Warehouse loading patterns and strategies