Power bi data gateway

hi meiyan 

Gateway is like a bridge between power bi service and data source and it is used for power bi service to connect to on-premises data source, power bi service could not connect to your on-premises data source directly, so it needs Gateway as a bridge for it.

Then if you use "Import" model, then the data will be stored on power bi service cloud, for "DirectQuery" and "Live connection" model, the data won't stored on power bi service cloud.

https://docs.microsoft.com/en-us/power-bi/desktop-directquery-about

When power bi service needs to connect to datasource, then gateway will work.

for example:

For "Import" model, when you refresh the dataset.

For "DirectQuery" and "Live connection", when you open the report/Interact with the report/ refresh the dataset cache.

Regards,

Lin