BUG: Non-Indexed Joins May Skip the Optimizer's Reformatting Step (172700)
The information in this article applies to:
This article was previously published under Q172700
BUG #: 16494 (6.5)
17158 (6.5)
SYMPTOMS
You may experience impaired performance when you process queries involving
joins on tables with no defined indexes. This problem has been identified
on SQL Server 6.5 only with Service Pack 2 and Service Pack 3 (and
intermediate builds between them). In one scenario, a query involving a non-
indexed join took approximately 840 minutes to execute on SQL Server 6.5
Service Pack 2, but only one minute on the release version of SQL Server
6.5. You may experience the degraded performance whether you use an ad-hoc
query or execute it within a stored procedure.
CAUSE
The Optimizer skips the Reformatting step for large tables with no indexes
defined. Earlier versions of SQL Server benefit significantly with the
Reformatting step included.
WORKAROUND
To work around this problem, define indexes on the tables.
STATUS
Microsoft has confirmed this to be a problem in Microsoft SQL Server
version 6.5. We are researching this problem and will post new information
here in the Microsoft Knowledge Base as it becomes available.
Modification Type: | Major | Last Reviewed: | 10/3/2003 |
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Keywords: | kbBug kbusage KB172700 |
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