FIX: A DAX query that contains SWITCH and nested IF statements takes more than an hour to finish in SQL Server

Applies to: SQL Server 2017 DeveloperSQL Server 2017 EnterpriseSQL Server 2017 Enterprise Core More

Symptoms


Assume that you run Data Analysis Expressions (DAX) queries in Microsoft SQL Server 2017. When you execute a DAX query that contains SWITCH and nested IF statements, if the SWITCH branch is the last in the branch list, the query may take more than an hour to finish. However, if the SWITCH branch is the first in the branch list, the query only takes several seconds to finish.

Resolution


This fix is included in the following update for SQL Server:

Cumulative Update 8 for SQL Server 2017

Status


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

References


Learn about the standard terminology that Microsoft uses to describe software updates.