Re: howto force use of indices on one table

Hi Sven,

    You probably didn't do anything wrong. It sounds like once you are down to 1/4 of the table everything fits into RAM. If so it is faster to do full scans in RAM than to attempt further data reduction.

regards

Jerry Gitomer

Sven G. wrote in message <374E64B6.9BD01784_at_informatik.tu-chemnitz.de>...
>Moin,
>
>I got a table with 10 float columns (a0 .. a9) and 600000 rows. I
>created indices for each column. But when I do a select (exact or range
>match) on 2 or more columns Oracle uses only one index.
>
>At first all values per column were distinct. Than I tried only 4
>diffrent values per column. So querying a concrete value in one column
>selects 1/4 of all. I expect Oracle using the index of the next column
>to get (1/4)/4 of all and so on, instead it does a full scan of 1/4.
>
>My settings:
>optimizer goal : first_rows
>analyzed the table and each index
>
>Can anyone tell me what I did wrong?
>
>thx
> Sven
>
Received on Fri May 28 1999 - 09:33:16 CDT