Re: Display only part of resultset (ORA 8.1.7)

Frank van Bortel <fbortel_at_nescape.net> wrote in message news:<bscmc1$q5u$1_at_news3.tilbu1.nb.home.nl>...
> Galen Boyer wrote:
>
> > On Tue, 23 Dec 2003, fbortel_at_nescape.net wrote:
> >
> >
> >>Don't use the view! Use the underlying query instead;
> >>it'll give Oracle the opportunity to use a better plan.
> >>
> >>Rule # 7: do not use views in joins (modified)
> >
> >
> > Care to explain?
>
> A view itself has an underlying query. I have seen too much
> code, based on joins of views leading to, eerrr, sub-optimal
> performance.
>
> Rule #7 of some Basic Performance Tips document stated not to
> code joins over views, but use the underlying statement, or
> create a new view.
> The modification is mine: there's no join here.

btw, that 'can' happen... but there is more going on. Typically its because you dont have accurate statistics or because your view is doing alot of extraneous work not needed in the given query.

Ruling them out always is stupid and short sited. Received on Fri Dec 26 2003 - 11:15:25 CST