Dataflow adding a rename step for long column names

[Jgordon20]

We're having an issue with our dataflow where upon saving and closing, it will add a column rename step. If we remove the step, it will be re-added. The rename step appears to be truncating and column name longer than 80 characters. This behaivour started only very recently, and all the datasets that pulled from this flow are now unable to refresh. Does anyone know why the column names are being shortened? I have not been able to find any documentation that mentions a column name limit in the PBI service, nor any kind of warning that this "feature" was coming down the pipe. 

Example of the column names that are being truncated:

Initial Conditional Approval to Final Borrower Approval (CX.PC.INITCONDAPPRTOBORRAPPR)
Milestone - Approved With Conditions DateTime (LOG.MS.DATETIME.APPROVED WITH CONDITIONS)

Shortened to

Initial Conditional Approval to Final Borrower Approval (CX.PC.INITCONDAPPRTOBOR
Milestone - Approved With Conditions DateTime (LOG.MS.DATETIME.APPROVED WITH CON

[Anonymous]

Hi @Jgordon20 ,

This seems to be an limitation. 

Best Regards

Community Support Team _ Polly

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[edhans]

That is a limit if the name of the query @Anonymous , not field names. If it applies to field names than that documentation needs to be updated. Field names though do not have such a limitation in other products like Power BI, so either this is a new limit for other reasons (downstream products in dev for example) or it is a bug.

[edhans · Accepted solution]

MS just improved the dataflow schema validation, and one of the things it does is fix issues, and apparently column names over 80 chars is an issue downstream somewhere. 

I will try to find out more, but honestly, super long column names are bad practice. I cannot imagine writing DAX dealing with column names like that.