Re: What is the trick to calculating the size of an index in 8.1.7 on a 64 bit machine?

Hi

I am afraid calculating the index size cannot be very accurate since there are little little overheads which add up. You can very well assume that formulas oracle provides are the most accurate. Usually there would be some small overheads and they add up

If you have a table A with a billion records, create another table with the same structure with 100000 record table (Create table B as Select * from Table A where ROWNUM < 100000) . manually create the index . See the impact on database size. If you get a 5 % error on this compared to your formulas, then you will in all probability get a 5 % error with a billion record table.

If you dont like this approach, try estimating the index size with TOAD (quest.com), revealnet Oracle DBA admin manual (revealnet.com) and choose one that is more accurate
(BTW i am not a vendor)

"Maggie Evans" <maggie-evans_at_home.com> wrote in message news:<38vu7.44111$L8.11043294_at_news2.rdc1.bc.home.com>...
> The formula they provide in the DBA text is way off. 5% of a billion records
> really
> adds up.
>
> Can somebody point me to a
> more accurate formula.
>
> Thanks in advance for any help
> owen brandon in victoria, b.c.
Received on Wed Oct 03 2001 - 02:05:01 CDT