Forum Discussion
Gen 2 dataflows extremely slow vs. Gen 1 dataflow
I'm finding Gen 2 dataflows in Fabric to be much slower than Gen 1 dataflows. Notably when pulling from an Excel file. I created a Gen 1 and Gen 2 dataflow with identical M-code in the same Fabr...
Just struck this same issue in an existing semantic model where I needed to convert some of the inputs from Gen1 to Gen2 dataflow. Previously it would refresh in around 2 minutes in the web service (Premium capacity), but after that change, it did not complete after 90 minutes. I also noticed the Query Editor became very sluggish, would not refresh for some more complex queries built on the Gen2 data. Note no issues previously with Gen1.
Following a hunch I added Table.Buffer steps to the end of each Gen2 query. I keep these brief so the steps are just:
Source
Navigation
Table.Buffer
With those in place, Query Editor performance was good again. A web service refresh completed in 2 minutes. This seems a useful workaround (YMMV).