Re: column masking in 10g
- From: "Alexander Fatkulin" <afatkulin@xxxxxxxxx>
- To: "David Boyd" <davidb158@xxxxxxxxxxx>
- Date: Fri, 2 Mar 2007 13:07:22 +1000
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@xxxxxxxxxxx> 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
--
//www.freelists.org/webpage/oracle-l
Other related posts:
