Symptoms
Assume that you have a Multidimensional OLAP (MOLAP) dimension that has enabled the Proactive Caching feature in Microsoft SQL Server Analysis Service (SSAS) and the dimension is referenced by a cube that has a Relational OLAP (ROLAP) partition. When data changes in the source database cause proactive caching to be triggered for the dimension, a crash occurs, and you receive the following error message:
Internal error: An unexpected error occurred (file 'FileName', line LineNumber, function 'FunctionName').
Resolution
The issue is fixed in the following cumulative updates for SQL Server:
Cumulative Update 8 for SQL Server 2017
Cumulative Update 1 for SQL Server 2016 Service Pack 2
Cumulative Update 9 for SQL Server 2016 Service Pack 1
Cumulative Update 2 for SQL Server 2014 SP1
Cumulative Update 6 for SQL Server 2014
Cumulative Update 4 for SQL Server 2012 SP2
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, use Hybrid OLAP (HOLAP) mode instead of Relational OLAP (ROLAP) mode in SSAS 2012.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
