看索引內部的總結

oracle_index_internals.pdf

引用頁 http://www.itpub.net/478038.html

Summary Summary
The vast majority of indexes do not require rebuilding Oracle B-tree indexes can become “unbalanced” and need to be rebuilt is a myth

Deleted space in an index is “deadwood” and over time
requires the index to be rebuilt is a myth

If an index reaches “x” number of levels, it becomes
inefficient and requires the index to be rebuilt is a myth

If an index has a poor clustering factor, the index needs to be rebuilt is a myth

To improve performance, indexes need to be regularly
rebuilt is a myth