Assume that you enable Query Store in SQL Server 2016 and 2017. When you run the command ALTER DATABASE <DatabaseName> SET QUERY_STORE CLEAR on a very busy database, you may notice that the transactions and log truncation will be blocked by a Query Store background thread.
This issue is fixed in the following cumulative updates for SQL Server:
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Learn about the terminology that Microsoft uses to describe software updates.