FIX: A query filter condition that has a LEFT OUTER JOIN clause may cause an incorrect row count estimate in the query execution plan (821688)


The information in this article applies to:

  • Microsoft SQL Server 2000 (all editions) SP3
Bug #: 469608 (SQL Server 8.0)
SQL Server 8.0:469608
Microsoft distributes hotfixes for Microsoft SQL Server 2000 as one downloadable file. Because these fixes are cumulative, each new release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2000 hotfix release.

SYMPTOMS

When you run a query that references a derived table or a view that is defined by a query that contains a LEFT OUTER JOIN clause, the query execution plan may display an incorrect row count estimate for the filter condition in the query. This problem may occur if the filter condition in the query references a column that is involved in the LEFT OUTER JOIN condition in the derived table query or in the view definition query.

Note This is a regression in SQL Server 2000 Service Pack 3 (SP3).

RESOLUTION

Service pack information

To resolve this problem, obtain the latest service pack for Microsoft SQL Server 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

290211 How to obtain the latest SQL Server 2000 service pack

Hotfix information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
   Date         Time   Version             Size   File name
   ---------------------------------------------------------------------
   31-May-2003  18:45  2000.80.818.0      78,400  Console.exe
   15-Jul-2003  16:11  2000.80.818.0      33,340  Dbmslpcn.dll
   25-Apr-2003  02:12                    786,432  Distmdl.ldf
   25-Apr-2003  02:12                  2,359,296  Distmdl.mdf
   30-Jan-2003  01:55                        180  Drop_repl_hotfix.sql
   07-Apr-2003  19:15  2000.80.801.0   1,557,052  Dtsui.dll
   24-Apr-2003  02:51                    747,927  Instdist.sql
   03-May-2003  01:56                      1,581  Inst_repl_hotfix.sql
   08-Feb-2003  06:40  2000.80.765.0      90,692  Msgprox.dll
   01-Apr-2003  02:07                      1,873  Odsole.sql
   05-Apr-2003  01:46  2000.80.800.0      62,024  Odsole70.dll
   02-Apr-2003  21:48  2000.80.796.0      57,904  Osql.exe
   02-Apr-2003  23:15  2000.80.797.0     279,104  Pfutil80.dll
   04-Apr-2003  21:27                  1,083,467  Replmerg.sql
   04-Apr-2003  21:53  2000.80.798.0     221,768  Replprov.dll
   08-Feb-2003  06:40  2000.80.765.0     307,784  Replrec.dll
   05-May-2003  00:05                  1,085,874  Replsys.sql
   01-Jun-2003  01:01  2000.80.818.0     492,096  Semobj.dll
   31-May-2003  18:27  2000.80.818.0     172,032  Semobj.rll
   29-May-2003  00:29                    115,944  Sp3_serv_uni.sql
   01-Jun-2003  01:01  2000.80.818.0   4,215,360  Sqldmo.dll
   07-Apr-2003  17:44                     25,172  Sqldumper.exe
   19-Mar-2003  18:20  2000.80.789.0      28,672  Sqlevn70.rll
   24-Apr-2003  05:39  2000.80.811.0     176,696  Sqlmap70.dll
   08-Feb-2003  06:40  2000.80.765.0      57,920  Sqlrepss.dll
   01-Jun-2003  01:02  2000.80.818.0   7,544,916  Sqlservr.exe     
   08-Feb-2003  06:40  2000.80.765.0      45,644  Sqlvdi.dll       
   15-Jul-2003  16:11  2000.80.818.0      33,340  Ssmslpcn.dll
   01-Jun-2003  01:01  2000.80.818.0      82,492  Ssnetlib.dll
   01-Jun-2003  01:01  2000.80.818.0      25,148  Ssnmpn70.dll
   01-Jun-2003  01:01  2000.80.818.0     158,240  Svrnetcn.dll
   31-May-2003  18:59  2000.80.818.0      76,416  Svrnetcn.exe
   30-Apr-2003  23:52  2000.80.816.0      45,132  Ums.dll
   28-Feb-2003  01:34  2000.80.778.0      98,872  Xpweb70.dll
Note Because of file dependencies, the most recent hotfix or feature that contains these files may also contain additional files.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.This problem was first corrected in Microsoft SQL Server 2000 Service Pack 4.

MORE INFORMATION

For this hotfix to take effect, you must enable SQL Server trace flag 9210. To enable a trace flag for an instance of SQL Server, use one of the following methods:
  • Run the following Transact-SQL statement on the instance of SQL Server:
    DBCC TRACEON (9210)
  • Set the trace flag 9210 as a server-wide trace flag by using the -T startup parameter in SQL Server. To do so, run the following command at a command prompt:
    sqlservr -d"Full path of the Master.mdf file for the instance of SQL Server" -T9210

REFERENCES

For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

830887 FIX: Some queries that have a left outer join and an IS NULL filter run slower after you install SQL Server 2000 post-SP3 hotfix

Modification Type:MinorLast Reviewed:10/25/2005
Keywords:kbHotfixServer kbQFE kbQFE kbView kbQuery kbPerformance kbDatabase kbSQLServ2000preSP4fix kbfix kbbug KB821688 kbAudDeveloper
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