FIX: Assertion occurs when you use parallel redo in a secondary replica of SQL Server 2016 AG

Applies to: SQL Server 2016 DeveloperSQL Server 2016 EnterpriseSQL Server 2016 Enterprise Core More


Consider the following scenario:

  • You have a readable secondary replica of Microsoft SQL Server 2016 AlwaysOn Availability Groups (AG).
  • You use parallel redo instead of single thread redo.

In this scenario, you will notice that assertion occurs with a memory dump, and data movement may be suspended. Additionally, you may receive an error message that resembles the following: 

Failed Assertion = 'false' Invalid dptEntry.


This issue is fixed in the following cumulative update for SQL Server:

       Cumulative Update 4 for SQL Server 2016 SP2


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.


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