Symptoms
Consider the following scenario:
-
You have Microsoft SQL Server 2014 installed on a computer.
-
You have poorly configured disk caching or failed raid setup, or both. This results in an inconsistent cache state.
-
You run the query DBCC CHECKTABLE against a table that contains the clustered column store index.
In this scenario, an access violation occurs.
Cause
The issue occurs because drives that support some kinds of disk caching may not always accurately reflect the state of the disk. When the system is ended, the cache can be lost and leave the system in an inconsistent state. Therefore, the expected cache lookup values can be null.
Resolution
The issue was first fixed in the following cumulative update of SQL Server.
Cumulative Update 1 for SQL Server 2014 /en-us/help/2931693
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:
Workaround
To work around the issue, configure disks correctly to avoid disk inconsistencies. You should make sure that disk caching is set to off and stripe sets are aligned on page size (8kb).
For more information, you can view Disk Partition Alignment Best Practices for SQL Server.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
