Symptoms
Assume that you create a columnstore index on a table that has a clustered index and has no non-clustered index in Microsoft SQL Server 2012 or SQL Server 2014. When you run UPDATE STATISTICS on the clustered index, incorrect sample percent is applied, and the histogram steps do not represent the correct data distribution. You can view the result by running the following command after you update the statistics:
DBCC SHOW_STATISTICS ( table_or_indexed_view_name , target ) WITH STAT_HEADER
In this situation, the statistical updating might take a longer time, and the incorrect histogram steps can cause sub-optimal query execution plans.Note This issue also occurs in SQL Server 2012 Cumulative Update 8 (CU8) or the later versions.
Resolution
The issue was first fixed in the following cumulative update of SQL Server.
Cumulative Update 4 for SQL Server 2014 /en-us/help/2999197
Cumulative Update 2 for SQL Server 2012 SP2 /en-us/help/2983175
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 this issue, add a non-clustered index on the table.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
