Re: Deadly sins againts database performance/scalability

Where you have skewed data would be the classic example.

select employee_name,salary
from emp
where dept='FACTORY FLOOR';

might be expected to run optimally with a FTS.

select employee_name,salary
from emp
where dept='CEO OFFICE';

probably would best use an index scan. Assuming a reasonable proportion of workers to chief execs :(

if you issue

select employee_name,salary
from emp
where dept=:b1;

which are you going to want?

-- 
Niall Litchfield
Oracle DBA
Audit Commission UK

-- 
Niall Litchfield
Oracle DBA
Audit Commission UK
"Daniel Morgan" <damorgan_at_x.washington.edu> wrote in message
news:1069957744.97573_at_yasure...


> Niall Litchfield wrote:

>

> > Actually I'm beginning to regret that post now.

> >

> > As Joel rightly says there is a real danger in creating a list like that

> > one. In my case my post might just have suggested that one should always

use


> > bind variables (I believe you could read it that way :) ) and this is of

> > course untrue, one should always use them, except where they are

> > inappropriate.

> >

>

> And they are in appropriate ... when?

>

> -- 

> Daniel Morgan

> http://www.outreach.washington.edu/ext/certificates/oad/oad_crs.asp

> http://www.outreach.washington.edu/ext/certificates/aoa/aoa_crs.asp

> damorgan_at_x.washington.edu

> (replace 'x' with a 'u' to reply)

>