FIX: Sequence object generates duplicate sequence values when SQL Server 2012 or SQL Server 2014 is under memory pressure

Applies to: SQL Server 2012 DeveloperSQL Server 2012 EnterpriseSQL Server 2012 Standard

Symptoms


Assume that you create a sequence object that has the CACHE option enabled in Microsoft SQL Server 2012 or SQL Server 2014. When the instance is under memory pressure, and multiple concurrent connections request sequence values from the same sequence object, duplicate sequence values may be generated. In addition, a unique or primary key (PK) violation error occurs when the duplicate sequence value is inserted into a table.

Resolution


The issue was first fixed in the following cumulative update of SQL Server.

Cumulative Update 6 for SQL Server 2014

Cumulative Update 4 for SQL Server 2012 SP2

Status


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