SQL Service Stretch Database was introduced in SQL Server 2016, and is a feature that can move or archive your cold data from your on-premises SQL Server to the Azure SQL Database. This results in better performance for your on-premises server, and the stretched data resides in the cloud, where it is easily accessible for other applications.
Inside SQL Server, you can mark a table as a stretch candidate, and SQL Server will move the data to Azure SQL Database transparently. Large transactional tables with lots of historical data can benefit from enabling for stretch. These are mostly massive tables with hundreds or millions of rows in them, which don't have to be queried frequently.
