Re: Indexes, performance and storage

No need to apologise - the principles are still the same. It now looks as if your index column is typically about 8 bytes.

The bitmap sizing also suggests that there really are very few distinct values in the index and that a b-tree is not likely to be of much use.

--
Jonathan Lewis
http://www.jlcomp.demon.co.uk

Host to The Co-Operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html

Author of:
Practical Oracle 8i: Building Efficient Databases

Screen saver or Life saver: http://www.ud.com
Use spare CPU to assist in cancer research.

Stephen B wrote in message ...


>Jonathan,

>

>Please accept my deepest apologies...it was my typing that caused your

>confusion..

>The number of rows should read 20.3 million, not 2.3 million..

>

>"Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote in message

>news:1007119437.18569.0.nnrp-10.9e984b29_at_news.demon.co.uk...

>>

>> There is something a little unusual about

>> your data - you have 2.3 million rows, but

>> 2.5 GB of data, which indicates 1K per row,

>> and the b-tree index you create takes

>> 432MB which suggests the average length

>> of the identifier (when used) is about 155 bytes.

>> Is your figure for the number of rows correct ?