Issues with reverse key indexes and range scan

Question

I have a question. Why is it that reverse key indexes do not work in a range scan?
Thanks

Answer 1

Chris, well said in simple terms.
Extract from metalink:
Oracle8 provides the ability to create reverse key indexes. Reverse key indexes
reverse the bytes of each indexed column with the exception of ROWID and still
maintains the column order. Reverse key indexes are useful for Oracle Parallel
Server environments.
In an OPS environment, modifications to indexes are focused on a small
set of leaf blocks. Reversing the keys of the index allows insertions to be
distributed across all the leaf keys in the index. Reverse key indexes prevent
queries from performing an index range scan since lexically adjacent keys
are not stored next to each other. Reverse key indexes can also be used in
situations where users insert ascending values and delete lower values from the
table, thus helping to prevent skewed indexes.
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Good discussion at
http://asktom.oracle.com/pls/ask/f?p=4950:8:2737861489787945222::NO::F4950_P8_DISPLAYID,F4950_P8_CRITERIA:627823669999
http://asktom.oracle.com/pls/ask/f?p=4950:8:2737861489787945222::NO::F4950_P8_DISPLAYID,F4950_P8_CRITERIA:6163160472530
Jaffar
Message was edited by:
The Human Fly