The result is that applications are released into production without any
way to guarantee that the functionality and performance of the application as a whole will meet
the needs of the users. This is a serious and significant flaw and should not be tolerated by any
user of the application. Users do not need just one component of the application to function
properly; they need the entire application to work properly in support of a business process.
If they cannot do a day??™s worth of business in a day, the application fails.
This is a key tenet regarding identifying the need for tuning: If the application slows the speed
of the business process, it should be tuned. The tests you perform must be able to determine if the
application will hinder the speed of the business process under the expected production load.
Test with Large Volumes of Data
As described earlier in this chapter, objects within the database function differently after they have
been used for some time. For example, a table??™s pctfree and pctused settings may make it likely that
blocks will be only half-used or rows will be chained. Each of these scenarios causes performance
problems that will only be seen after the application has been used for some time.
132 Oracle Database 11g DBA Handbook
A further problem with data volume concerns indexes. As a B-tree index grows in size, it may
split internally??”the level of entries within the index increases.
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