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11.26.2007 at 11:35AM PST, ID: 22983243
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Adding Indexes to Table hurts query performance (self-join)

Asked by JaffaKREE in MS SQL Server

Tags: join, self, sql, table, performance

I'm optimizing a query on SQL 2000.  The query joins a single table to itself 5 times to get various MAX(values).  

When I add a large covering clustered (or non-clustered index) to the table to help the query, performance suffers greatly.  This is a select statement only.

Why would a large index negatively impact read performance ?Start Free Trial
[+][-]11.26.2007 at 11:43AM PST, ID: 20352377

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[+][-]11.26.2007 at 11:52AM PST, ID: 20352448

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[+][-]11.26.2007 at 11:56AM PST, ID: 20352475

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About this solution

Zone: MS SQL Server
Tags: join, self, sql, table, performance
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Solution Provided By: JR2003
Participating Experts: 2
Solution Grade: A
 
 
[+][-]11.26.2007 at 12:07PM PST, ID: 20352547

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