FIX: Numeric and Decimal Datatypes Do Not Always Use an Index

• Microsoft SQL Server version 6.5

SYMPTOMS

A query can be very slow if the qualifying column used in the where clause is either a numeric or decimal data type. The query can be slow even if the columns have indexes. A show plan of the query shows that the optimizer chooses to do a table scan rather than use the index.

This problem only occurs in Microsoft SQL Server version 6.5 Service Pack 2. Earlier versions of SQL Server do not have this problem.

WORKAROUND

Change your query to use another column as the qualifier, or use a composite index with the first part of the index key not being a decimal or numeric data type. Another workaround is to change the qualifying column used in the where clause to truly be numeric or decimal. For example, instead of using 9, use 9.0, or do a convert to numeric or decimal.

STATUS

Microsoft has confirmed this to be a problem in SQL Server version 6.5. This problem has been corrected in U.S. Service Pack 5a for Microsoft SQL Server version 6.5. For information about downloading and installing the latest SQL Server Service Pack, see http://support.microsoft.com/support/sql/.

For more information, contact your primary support provider.

Additional query words:

Keywords          : kbusage SSrvGen kbbug6.50.sp2 
Version           : winnt:6.5
Platform          : winnt 
Issue type        : kbbug 

Last Reviewed: June 24, 1999