FIX: Query Slow w/ ORDER BY DESC on Table w/ Composite Index

Last reviewed: June 27, 1997
Article ID: Q167779

The information in this article applies to:

Microsoft SQL Server, version 6.5

BUG #: 16669 (6.5)

SYMPTOMS

An ORDER BY DESC query against a table that has a non-clustered composite index may take significantly longer to run than the equivalent ASC query. This difference is especially noticed in cases in which a WHERE clause contains an equivalency test of an indexed column (including the most significant) and a constant value.

WORKAROUND

To work around this problem, select the result set (ASC) into a temporary table, then run the ORDER BY DESC query only on the results of a select from the temporary table.

Another option, for certain numeric columns, is to multiply the key by -1 and then run the ORDER BY ASC query.

STATUS

Microsoft has confirmed this to be a problem in Microsoft SQL Server version 6.5. This problem has been corrected in U.S. Service Pack 3 for Microsoft SQL Server version 6.5. For more information, contact your primary support provider.

Additional query words: descending
Keywords : kbbug6.50 kbprg kbusage SSrvGen SSrvProg
Version : 6.5
Platform : WINDOWS
Issue type : kbbug
Resolution Type : kbfix

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Last reviewed: June 27, 1997
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