FIX: SQL 7.0 Slower than SQL 6.5 on Multiple Left Outer Join

ID: Q244548

The information in this article applies to:

Microsoft SQL Server version 7.0

BUG #: 56085 (SQLBUG_70)

SYMPTOMS

SQL Server 7.0 may infrequently be slower than SQL Server 6.5 when you run certain rare types of left outer joins that involve large result sets.

RESOLUTION

A supported fix that corrects this problem is now available from Microsoft, but it has not been fully regression tested and should be applied only to systems experiencing this specific problem. If you are not severely affected by this specific problem, Microsoft recommends that you wait for the next SQL Server service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

http://www.microsoft.com/support/supportnet/overview/overview.asp

The English version of this fix should have the following file attributes or later:


   Date       Time     Version    Size         File name     Platform
   ------------------------------------------------------------------

   10/05/99   09:27p   7.00.735   15,737,858   S70735A.exe   Alpha
   10/05/99   09:05p   7.00.735    9,447,224   S70735I.exe   Intel

NOTE: Due to file dependencies, the most recent hotfix or feature that contains the above files may also contain additional files.

NOTE: If this product was already installed on your computer when you purchased it from the Original Equipment Manufacturer (OEM) and you need this fix, please call the Pay Per Incident number listed on the above Web site. If you contact Microsoft to obtain this fix, and if it is determined that you only require the fix you requested, no fee will be charged. However, if you request additional technical support, and if your no-charge technical support period has expired, or if you are not eligible for standard no-charge technical support, you may be charged a non-refundable fee.

For more information about eligibility for no-charge technical support, see the following article in the Microsoft Knowledge Base:

Q154871 Determining If You Are Eligible for No-Charge Technical Support

STATUS

Microsoft has confirmed this to be a problem in SQL Server version 7.0.

MORE INFORMATION

To achieve the full benefit of this hotfix, it may be necessary to use the optimizer hint: option (loop join, force order). For more information, see SQL Server Books Online for details about using optimizer hints. It may also be necessary to make sure that clustered indexes exist on the most beneficial columns for the query. Experimentation may be required to determine the best index placement.

Additional query words:

Keywords : kbSQLServ700bug
Version : winnt:7.0
Platform : winnt
Issue type : kbbug