Re: Access Path Tuning

If you specify a clause on a column that column willl be used. If you don't specify a clause that column will not be used. In a 3 column indexed when you don't specify a clause on column c, column c will not be used during index retrieval.
You can easily verify that by comparing tkprof results (where each intermediate step shows the number of rows retrieved) and the final outcome.

Hth,

Sybrand Bakker, Oracle DBA

Sybrand Bakker
Robert & Amelia Webb <rob_at_thewebbfamily.com> wrote in message news:88m5vv$jnl$1_at_nntp9.atl.mindspring.net...
> I am doing some access path tuning on Oracle 7.3.4 / Oracle 8.0. When I
use
> EXPLAIN PLAN I can easily tell which tables are being accessed and if the
> access is using an index. Is there a way to tell how many keys of the
index
> are being used?
>
> For example if I have an index on 2 columns A and B ( in that order) where
A
> has the same value for all rows and B is unique across all rows it would
be
> extremely helpful to determine if the indexes was being accessed on a
match
> of just column A or on both columns A and B.
>
> Thanks,
>
> Robert
>
>
Received on Sat Feb 19 2000 - 08:31:52 CST