FIX: UPDATE with FORCEPLAN ON May Cause Error 806 in Tempdb (171865)

The information in this article applies to:

Microsoft SQL Server 6.5

This article was previously published under Q171865

BUG #: 17089 (Windows NT: 6.5)

SYMPTOMS

If an UPDATE trigger fires and contains an UPDATE that joins with the inserted table, the following error may occur if SET FORCEPLAN is set ON and the sysindexes count for syslogs number of pages is high:

Msg 806, Level 21, State 1
Could not find virtual page for logical page <page#> in database
'tempdb'

WORKAROUND

To work around this problem, look for ways to avoid using SET FORCEPLAN ON with UPDATE statements including proper index design.

If you truncate the transaction log and/or run DBCC CHECKTABLE(syslogs) to update the sysindexes entries for syslogs, it is possible that the problem will not occur.

STATUS

Microsoft has confirmed this to be a problem in SQL Server version 6.5. This problem was corrected in the latest Microsoft SQL Server 6.5 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K

MORE INFORMATION

The following is a summary of the conditions that cause the problem to occur:

SET FORCEPLAN is set ON.
An UPDATE statement inside an UPDATE trigger joins with the inserted table.
The table being updated contains at least two rows.
The transaction log according to sysindexes.dpages has a large number of pages used.

Modification Type:	Major	Last Reviewed:	10/3/2003
Keywords:	kbBug kbfix kbSQLServ650bug kbusage KB171865 kbAudDeveloper