Re: How to calculate parameters for indexes?

Then as a guide line -

    Assume you don't pack your varchar2(20)     and number to full length, each index entry     is likely to be about 40 Bytes - (check on the     50,000 you already have).

    40 bytes x 10,000 rows per month = 400K     3 months is about 1 Mb.

I'd look at storing the index in a locally managed tablespace with uniform extents in the 1Mb region.

Bear in mind that apart from nominal size, you have to consider the effect that arriving data might have on splitting blocks etc, and leaving you with a sparsely populated index. You may get some idea from the existing data, or by checking the index in 3 months time when its not to big to rebuild quickly.

--

Jonathan Lewis
Yet another Oracle-related web site:  http://www.jlcomp.demon.co.uk

skadhane_at_my-deja.com wrote in message <8ooj17$ptm$1_at_nnrp1.deja.com>...


>What is the way to calculate parameters( initial and next) while

>creating indexes?

>

>Say i want to create a index on 4 columns of a table which has 50,000

>rows which has

>monthly growth of 10,000 rows.The columns are

>varchar2(20),number(10),varchar2(10),number.

>

>What factors will you consider so that it index wont use more no of

>extents.

>And what are the other things that should consider while creating

>indexes.

>

>Thanks

>

>SK

>

>

>Sent via Deja.com http://www.deja.com/

>Before you buy.