KB4581886 - FIX: Joins not getting pushed down for PolyBase query that joins multiple external tables

Applies to: SQL Server 2019 on Windows

Symptoms


Assume that you havea PolyBase query that joins multiple external tables from one or more externaldata sources that allow for join pushdown (that is, SQL Server, Oracle, Teradata,MongoDB, or Generic ODBC). When you run the query, you notice that thejoins are not pushed down to the external data sources. This condition usually occurs because of the presence of a global aggregation in at least one of the input operatortrees.

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.

Third-party information disclaimer
The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.