Importing data

Choosing to import data, which is the most common option and default behavior, means that Power BI will physically extract rows of data from the selected source and store it in an in-memory storage engine within Power BI. Power BI Desktop uses a special method for storing data, known as xVelocity, which is an in-memory technology that not only increases the performance of your query results but can also highly compress the amount of space taken up by your Power BI solution. In some cases, the compression that takes place can even lower the required disk space by up to one-tenth of the original data source size. This data compression occurs automatically, meaning there is no required configuration step you must do to receive this benefit. The xVelocity engine uses a local unseen instance of SQL Server Analysis Services (SSAS) to provide these in-memory capabilities.

There are consequences to using the Import option within Power BI that you should also consider....