You can use the group-switching features to minimize the impact of long-running jobs within
the database. You can configure consumer groups with different levels of access to the system
resources and customize them to support fast jobs as well as long-running jobs??”the ones that
reach the switch limit will be redirected to the appropriate groups before they even execute.
Implementing Stored Outlines
As you migrate from one database to another, the execution paths for your queries may change.
Your execution paths may change for several reasons:
You may have enabled different optimizer features in the different databases.
The statistics for the queried tables may differ in the databases.
The frequency with which statistics are gathered may differ among the databases.
The databases may be running different versions of the Oracle kernel.
The effects of these differences on your execution paths can be dramatic, and they can have
a negative impact on your query performance as you migrate or upgrade your application. To
minimize the impact of these differences on your query performance, you can use a feature called
a stored outline.
A stored outline stores a set of hints for a query. Those hints will be used every time the query is
executed. Using the stored hints will increase the likelihood that the query will use the same execution
path each time. Hints decrease the impact of database moves on your query performance.
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