Symptoms
Assume that you have an AlwaysOn Availability Group that contains many databases in SQL Server 2016. For example, you may have more than 100 databases. When you execute a query that requests data from the sys.dm_hadr_availability_replica_states function and the query contains many join operations, the query may take a longer time to complete when you compare it to an earlier version of SQL Server. Additionally, it may also cause high CPU usage.
Resolution
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:
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
References
Learn about the terminology Microsoft uses to describe software updates.