Resolution
To enable the new behavior, enable the SQL Server trace flag 6534.
The issue was first fixed in the following cumulative update of SQL Server.Cumulative Update 8 for SQL Server 2012 SP2 /en-us/help/3082561
Cumulative Update 9 for SQL Server 2014 /en-us/help/3075949
Cumulative Update 1 for SQL Server 2014 SP1 /en-us/help/3067839
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:
More Information
The Microsoft.SqlServer.Types objects support Microsoft SQL Server Spatial data types for the SQL Server service and the client applications. The logic to populate a LineString object involves validation. The validation logic sorts vertices during the validation. The more vertices, the more work for the algorithm. This fix updates the sorting algorithm to include angular vectorization techniques that significantly improve the LineString performance.
You can enable the new algorithm in client code:AppDomain.CurrentDomain.SetData("clr_feature_switch_map", 1);
Note This should only be set for one time. A crash may occur when you change it during the validation.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.