FIX: Incorrect choice of a nested loops join strategy causes poor query performance in SQL Server 2014

Applies to: SQL Server 2014 DeveloperSQL Server 2014 DeveloperSQL Server 2014 Enterprise

Symptoms


When you use Microsoft SQL Server 2014 to run a query that uses a nested loops join, you experience poor query performance when an incorrect choice of a query execution plan occurs.

Cause


This behavior occurs because the query optimizer chooses an incorrect nested loops join strategy when incorrect cardinality estimates or incorrect operator costing is used.

Resolution


This problem was first fixed in the following cumulative update for SQL Server:

Cumulative Update 1 for SQL Server 2014 SP1

Cumulative Update 7 for SQL Server 2014

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 terminology Microsoft uses to describe software updates.