When you use parallel redo instead of single thread redo in a secondary replica of a SQL Server 2016 AlwaysOn Availability Group, you may receive an assertion.
The fix for this issue is included 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:
To work around this issue, use a single thread redo instead of a parallel redo.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
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