> Superboer wrote:
> >>This is a funny way of looking at. Obviously
> Oracle's none locking
> >>engine is perfectly suited to scaling multi user
> applications,
> >>particularly when most people are developing for
> stateless clients.
> >
> > ahum does the above explain why informix was
> faster on a 5 times
> > smaller machine then obstacle...????
> >
> > Superboer.
> >
> Changed the subject lines and following up on what
> Knut started.
>
> How does Oracles snapshot isolation help with
> stateless clients.
> To the best of my knowledge snapshot semantics only
> operate on either a
> statement or a transaction level. In a stateless
> scenario I'd assume
> that teh application transaction covers at least two
> database
> transactions. A read phase wher the resultset is
> displayed at the client
> and a separate write phase where the modified data
> is written back.
> How does snapshot isolation help here?
> Informix supports versioning columns which can be
> used by the app to
> prevent overwriting other users changes across DB
> transaction boundaries.
> MS SQL server has a somewhat similar approach and
> even buried optimistic
> locking into the cursor logic (not applicable in a
> stateless enviroment
> (no cursor open).
> I see tha value of snapshot isolation for certain
> purposes. I don't see
> it for a 3 tier web application....
>
> Thoughts?
> Cheers
> Serge