March 2007
Intermediate to advanced
488 pages
13h 46m
English
book
OnDemand SQL Performance Analysis Simplified on DB2 for i5/OS in V5R4
by Hernando Bedoya, Jaime Gaug, James Kerl, Ser Ser NG, Jose Cardoso dos Santos
Content preview from OnDemand SQL Performance Analysis Simplified on DB2 for i5/OS in V5R4
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Chapter 5. Analyzing SQL performance data using iSeries Navigator 157
5.6.1 A poor performing SQL statement
In this example, we have an SQL application which joins rows from a customer table and an
order table. The application takes about a minute to read order information for 50 customers.
The SQL statement being used in the application to retrieve the order information is shown in
Example 5-1.
Example 5-1 Join operation from Customer table and Order table
SELECT O . *
FROM ORDERS O , CUSTOMERS C
WHERE O . CUSTKEY = C . CUSTKEY
AND C . CUSTOMER = ?
We want to tune this query and improve its performance.
As the first step to any SQL performance analysis, ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.