Re: column masking in 10g

Dave, It depends.

As long as you can get with simple SQL inline predicates the performance will virtually be the same

e.g.

create view v_t2 as

	select n, case mod(n, 2) when 0 then m else null end m
		from t2;

will perform virtually the same (from both elapsed time / latches) as column masking using the policy function with the "return 'mod(n,2)=0' " predicate. Don't forget I'm talking about _static_ policies here,

BUT as long as you start using PL/SQL functions in a view - the performance will significantly degrade (mostly due to context switches between engines). The subquery caching (don't forget to declare function as a deterministic) can help you but anyway - it has it's own limitations.

As always - don't forget to test for your own specific cases.

On 3/2/07, David Boyd <davidb158_at_hotmail.com> wrote:
> Alexander,
>
> This works great for me. Thanks so much.
>
> Did you have experience on the performance between VPD and view?
>
> Dave
>

-- 
Alexander Fatkulin,
Senior Oracle DBA
--
http://www.freelists.org/webpage/oracle-l