Symptoms
Assume that you create a clustered columnstore index through a Multiple Active Result Sets (MARS) connection in Microsoft SQL Server 2014. When you set the value of maxdop larger than 1, building or rebuilding the clustered columnstore index fails. Additionally, you receive error 35377 resembles the following:
ErrorNumber: 35377ErrorSeverity: EX_USERErrorOwner: <OwnerName>rrorFormat: When MARS is on, accessing clustered columnstore indexes is not allowed.ErrorCause: Invalid access to clustered columnstore indexes on a MARS connection.ErrorCorrectiveAction: Connection should not be MARS-enabled.ErrorFirstProduct: SQL14
Note This issue does not occur when you set maxdop equal to 1.
Resolution
The both issues were 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:
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
