KB4574801 - FIX: Incorrect results occur when you run PolyBase query to read text files from Hadoop in SQL Server 2019

Applies to: SQL Server 2019 on WindowsSQL Server 2019 on Linux

Symptoms


Assume that you use SQL Server PolyBase query to read text files from Hadoop. When the following conditions are met, you may notice that the results returned are wrong:
  • The file doesn't contain a byte order mark (BOM).
  • The file starts with a null value.
  • The total number of bytes in the file is equal to the number of bytes in the BOM sequence. For example: 2 for UTF16 and 3 for UTF8.

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:

Workaround


To work around this issue, you may manually modify the file on the Hadoop cluster so that the conditions are not met.

References


Learn about the terminology that Microsoft uses to describe software updates.