Symptoms
Assume that you use Microsoft SQL Server 2012 or 2014 Always On Availability Groups. After statistics are updated by using the FULLSCAN option on the primary replica, the statistics on the secondary replica become stale or out-of-date. When you run a query on the secondary replica, a bad query plan might be used. This causes slow queries.
Resolution
Cumulative Update Information for SQL Server:
This issue is fixed in the following cumulative updates for SQL Server:
Cumulative Update 5 for SQL Server 2014 SP2
Each new cumulative update for SQL Server contains all the hotfixes and security fixes that were included in the previous cumulative update. Check out the latest cumulative updates for SQL Server:
Service Pack Information for SQL Server 2012:
This issue is fixed in the following service pack for SQL Server:
Service Pack 4 for SQL Server 2012
For more information about how to obtain the latest service pack, see How to obtain the latest service pack for SQL Server 2012
Service packs are cumulative. Each new service pack contains all the fixes that are in previous service packs, together with any new fixes. Our recommendation is to apply the latest service pack and the latest cumulative update for that service pack. You do not have to install a previous service pack before you install the latest service pack. Use Table 1 in the following article for finding more information about the latest service pack and latest cumulative update.
How to determine the version, edition and update level of SQL Server and its components
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 that Microsoft uses to describe software updates.