Oracle Logbook

March 25, 2011

Bitmap or Btree

Filed under: Uncategorized — Helio Dias @ 3:35 pm

Today I faced with this question at:

========================================= The Question ================

I have a table having 5 million records.

If I want to build an index on one column,which index is better(bitmap or btree normal)?

The column had approx 6% different values for the total records in the table.


My answer was:

With 5%, I’d go through btree,
bitmap have many detail that you should be aware.

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