Dataflow - Failed to analyze issues in the query

I had the same issue.

It worked OK with a small dataset - for development - but failed with a larger one.

The approach I took was to set a parameter to either 'Development' or 'Production' and then limited the number of rows when it was set to development.  I then needed to externalise that parameter, because I couldn't change it without changing the dataflow and seeing the same problem again.  So I created an external table to keep the parameter values in and changed the parameter in the dataflow to a query that produced the necessary text from the loaded external table.

That's a workaround (kludge!) but it works.  I can then save the dataflow when it's in development mode ok; and externally update it to be in production.  The refresh works fine.

Note that the Gen2 dataflows don't seem to have this problem.