Formula.Firewall In Power Query

Chris Webb explains when you might get a Formula.Firewall error in Power BI or Power Query:

The important difference here is that there is now one step in this query instead of two: the query and the filtering take place in the same step. Even more importantly, regardless of the data privacy settings, the query fails with the error:

Formula.Firewall: Query ‘DimDate With Native Query Single Step Fails’ (step ‘Source’) references other queries or steps, so it may not directly access a data source. Please rebuild this data combination.

The problem here is that the Power Query engine is not allowed to access two different data sources originating from different queries in the same step – as far as I understand it this is because it makes it too hard for the engine to work out whether a step connects to a data source or not, and so which data privacy rules should be applied.

This is an interesting downside to putting in complex data privacy rules.

Related Posts

Flattening JSON In Power BI

Imke Feldmann shows how to flatten JSON data imported into Power BI: If you work with JSON documents that are new to you, it can be very helpful to fully expand JSON to see at a glance what’s in there. The following function has you covered for this task. It returns a table with all […]

Read More

Auto-Indentation In Power BI’s DAX Formula Bar

Chris Webb shows an easy-to-miss feature in Power BI: The other day I discovered something new (at least to me) while writing the DAX for a measure in Power BI Desktop: when you insert a new line in your DAX expression using SHIFT-ENTER it also auto-indents the code. I asked a few people if this was new […]

Read More

Categories

June 2017
MTWTFSS
« May Jul »
 1234
567891011
12131415161718
19202122232425
2627282930