If you have a slow DirectQuery report in Power BI one of the first questions you need to ask is how long the SQL queries that Power BI generates take to run. This is a more complicated question to answer than you might think, though, and in this post I’ll explain why.
I happen to have access to some of the famous New York taxi data in a Snowflake database, and in there is a table with trip data that has 173 million rows that I have a built a Power BI dataset from. The data and the database used are not really important here though – what is important is that it’s DirectQuery and a large-ish amount of data.
Read on for more information on how it all works.