FIX: Internal thread deadlock may occur on primary or secondary replica of availability group in SQL Server 2016 SP2 and 2017

Applies to: SQL Server 2017 on Windows (all editions)SQL Server 2016 DeveloperSQL Server 2016 Enterprise

Symptoms


Under following situation, internal thread deadlock may occuron primary or secondary replica of availability group in Microsoft SQL 2016 Service Pack 2 (SP2) and 2017 leading to log writer thread in a stuck state.
  • When you are adding multiple databases to AG using auto seeding and heavy write transactions are occurring on primary replica.
  • AG configuration is updated while there are heavy write transactions on primary replica.
When this issue occurs no changes from AG perspective getsflushed.

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 updates 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:

References


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