Assume that you use SQL Server 2019 with PolyBase feature installed. You may notice that a PolyBase query (against external tables) may hang in the situation where the Data Management software (DMS) service is in the process of restarting when the query is issued.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
This issue is fixed in thefollowing cumulative update for SQL Server:
Aboutcumulative updates for SQL Server:
Each new cumulativeupdate for SQL Server contains all the hotfixes and all the security fixes thatwere included with the previous cumulative update. Check out the latestcumulative updates for SQL Server:
To work around the issue, you can restart SQL Server on Big Data Cluster (BDC). On Windows system, you can justrestart the PolyBase services.