order of predicates affects CPU usage hence elapse time on sequent

From: Everton Elliott <everton_at_aapi.co.uk>
Date: 1998/02/01
Message-ID: <01bd2eef$1869f2e0$1e21a4c2@evertonco>#1/1

Hi,
I have seen a unusual thing:-

TABLE

---

A CHAR INDEX
B DATE INDEX
C CHAR INDEX
D CHAR INDEX
E CHAR select count(*) from TABLE
WHERE C='SSSS'
AND B between '10-JAN-97' and '10-JAN-98'

versus

select count(*) from TABLE

WHERE       B between '10-JAN-97' and '10-JAN-98'
AND       C='SSSS'

Under tkprof oracle 7.3 and under oracle 8.x I see that the IO are simular but
the CPU usage diffrent by a multiple of four and hence the elapse time are different. Full table scan is used for both query.

Why should swaping the 'AND' predicate cuase the CPU usage to change????

Cheers Received on Sun Feb 01 1998 - 00:00:00 CST