Microsoft KB Archive/916949

= Trace flag 2301 enables advanced optimizations that are specific to decision support queries in SQL Server 2005 =

Article ID: 916949

Article Last Modified on 3/23/2006

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APPLIES TO


 * Microsoft SQL Server 2005 Service Pack 1

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INTRODUCTION
In Microsoft SQL Server 2005, trace flag 2301 enables advanced optimizations that are specific to decision support queries. You should only enable trace flag 2301 for large data sets, such as a TPC Benchmark H (TPC-H) workload. TPC-H is a decision support benchmark that includes many business-related ad hoc queries. Usually, these queries are very complex and involve large data sets.



MORE INFORMATION
For TPC-H performance purposes, trace flag 2301 enables more accurate query run-time behavior modeling in the Microsoft SQL Server query optimizer. Typically, you would only need this trace flag for decision support processing of large data sets.

You can enable trace flag 2301 at startup or in a user session. This trace flag has either global-level or session-level effect. To enable trace flag 2301, use the DBCC TRACEON command or use –T 2301 as a startup parameter.

