Symptoms
Assume that you try to virtualize data that's a fixed width string type that uses PolyBase in SQL Server 2019. If the column width of the backend data exceeds SQL Server's limit on fixed width strings, PolyBase recommends using a fixed width string type with T-SQL's maximum size rather than a variable width LOB type.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Resolution
This issue is fixed in the following cumulative update for SQL Server:
About cumulative updates for SQL Server:
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. Check out the latest cumulative updates for SQL Server:
References
Learn about the terminology that Microsoft uses to describe software updates.
