Direct Query-Understanding The Works (Detecting Changes, Updating, Pulling Data, etc.)

[B_Caron]

Hello,

SO I have began using direct query and really appericiate it's live reporting capabilities.

However, I was curious how the gateway detects the changes and goes through large databases 40gbs+ and updates all of data.

I understand since BI Desktop/Service has a live connection with the database, it utilizes references to capture only the information being used without storing any data. But I still do not understand how it can pull such large data and find all the updates with a ten minute cycle. Does it utilize indexes, dictionaries, etc.?

My question: 

How does Enterprise Gateway detect database changes and pull such large on-prem data to update the data?

Let me know if you need more clarification, I feel my question is general so if you could point me in the right direction to gain better depth of Direct Query I'd greatly appericiate it.

Thanks,

BC

[Greg_Deckler · Accepted solution]

So, with Direct Query, you are not importing data at all. DirectQuery translates all DAX queries at run time to SQL statements, allowing real time access to the SQL Server source database.