Symptoms
Assume that you create statistics on a PolyBase external table that points to a view on a PolyBase external data source. When you run a query on the external table, you notice that the statistics are not used in the Cardinality estimates of the query plan. This occurs regardless of the type of external data source. This behavior occurs on all versions of SQL Server 2019 (Windows/Linux/Big Data Cluster).
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:
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.