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Lesson 7 Reorganizing an index-organized table
Objective Reorganize an index-organized table.

Reorganizing (IOT) index-organized Table

Similar courses on this website have demonstrated that there are instances when you should reorganize an index structure.
If you are consistently deleting values from one side of the index while adding rows to the other side, the index may become unbalanced, with the leaf nodes on one side of the index containing an increasing amount of empty and wasted space.
To restore balance to the index structure and remove these potential performance impediments, you must reorganize the index.
Because an index-organized table is stored in the exact same index structure as the index for a standard table, the same requirement for reorganization applies to this type of table.

Reorganization Process

The process of reorganizing an index-organized table requires four steps, as shown in the following SlideShow:

Export Data From Index Table
When you reload the data into the new index-organized table structure, you will automatically fill up all the leaf nodes, just as you would if you took the same set of actions against a normal index.
With an index, you can simply use the REBUILD clause as part of the ALTER INDEX statement, but in Oracle8 and earlier, this type of option was not available to you.
The next lesson is the module conclusion.