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FIX: Parallel Query on Four CPUs Using NLS Is Slower Than Two CPUs

This article was previously published under Q282175
This article has been archived. It is offered "as is" and will no longer be updated.
BUG #: 58078 (SQLBUG_70)
Parallel query performance on a computer with four CPUs is poorer than on a computer with two CPUs if you are using the National Language Support (NLS) sort order with the double-byte character set (DBCS).

You may encounter this problem if all of the following conditions are true:
  • You are using the NLS sort order with DBCS.
  • The query processor chooses the Parallelism physical operator.
  • The table has a column of character data type that is used by the Parallelism physical operator.
To work around this problem, do one of the following:
  • Use the binary sort order.

  • Restrict the number of threads in parallel plan execution, by using the "max degree of parallelism" option or MAXDOP query hint.
Microsoft has confirmed this to be a problem in SQL Server 7.0. This problem has been corrected in U.S. Service Pack 3 for Microsoft SQL Server 7.0. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
274799 INF: How to Obtain Service Pack 3 for Microsoft SQL Server 7.0 and Microsoft Data Engine (MSDE) 1.0
For more information, contact your primary support provider.
NLS Parallel Parallelism MAXDOP cpu processor processors proc procs

Article ID: 282175 - Last Review: 10/21/2013 04:57:30 - Revision: 2.1

Microsoft SQL Server 7.0 Standard Edition

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