Pennsylvania
Department of Public Welfare
Office of Information Systems
SQL Server
Performance Gathering
Version 1.0
March 11, 2004
DPW Business and Technical Standards Document
Revised 03/11/04
SQL Server Performance Gathering
Introduction
This document will show the users how to fine tune the performance of a SQL Stored Procedure
via the results of the execution plan.
Purpose
The purpose of this document is assisting the user in any performance tuning of a SQL Stored
Procedure.
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SQL Server Performance Gathering
1. Open Query Analyzer
2. Change to correct database and enter query in window, or open the stored procedure.
3. Along top bar in query analyzer, under query choose ‘show execution plan’
Diagram 1.
4. Run the query.
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5. The results will display in results window.
6. Choose execution plan tab in the results window to see the execution plan.
Diagram 2
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7. Review the execution plan and identify any potential bottlenecks.
Diagram 3
8. All execution plans total 100% cost, each step of plan adds up to 100%.
9. To find where highest cost is associated and analyze why, look for following bottlenecks:
a. Table scans
b. Hash/merge joins
c. Sorts
10. Once problem areas are identified, begin to look at how process can be made better.
a. Table scans, add indexes or choose different index
b. Hash/merge joins – can inner join be done or left or right outer joins,
can joins be broken up into correlated sub queries or smaller joins.
c. Sorts, can data be sorted in another way or broken up into smaller sorts.
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11. Use other tools such as SQL Profiler or Performance Monitor to review code.
Diagram 4
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12. Also look at index tuning wizard to help gain insight into what indexes are used or are
needed to improve performance.
Diagram 5
13. If additional assistance is still needed contact DBA to help improve performance.
14. Lastly, test all new processes with and without user load.
Determine baseline time before adding in complexity of multiple users.
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Document Change Log
Change
Date
03/11/04
Version
CR #
1.0
SQL Server Performance Gathering.doc
Change Description
Initial creation.
Author and
Organization
Kiley Milakovic
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