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Oracle
Enterprise Manager Tuning Pack
Indexes are optional structures associated
with tables and clusters that help improve the performance
of SQL queries against these objects. Oracle indexes
provide a faster access path to table data and, when properly
used, they are the primary means of reducing disk I/O.
However, creating an index can be time and space consuming,
therefore it is important to create only those indexes that
will clearly improve performance.
Oracle Enterprise Manager's SQL Analyze recommends
the optimal indexes for your application and workload.
The new Virtual Index Wizard allows the user to test a potential
index prior to actually building it in the database. The Wizard
uses the Oracle optimizer to evaluate the potential new index
for a selected SQL statement by building an explain plan that
is aware of it. The Virtual Index Wizard estimates the
percentage improvement in optimizer cost taking into account
the virtual index and provides a "before and after"
explain plan comparison. The projected improvement is
presented graphically as shown below:
Users can view a side-by-side comparison of
the explain plans, with and without the virtual index.
This allows the user to determine if the optimizer would use
the index once implemented and decide if the index should
be created.
For more information on the Virtual Index Wizard please see
our online
demo.
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Oracle9i
Database Daily Features
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