Consider the following scenario:
- In Microsoft SQL Server, you use Always On Availability Groups.
- On the secondary replica, you use a query plan that scans many pages to query a large table.
- No other tasks are running.
In this scenario, it takes about two times as long for the query to run as it does on the primary replica.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.