Re: Changing isolation level?

"D Alpern" <ivorykeyer88ns_at_nshotmail.com> wrote in message news:o2issvovpglsvpkbh0h0fj7alr4qoaq4g9_at_4ax.com...
> SELECT... FOR UPDATE {WAIT | NOWAIT} springs to mind...

I suppose that could help. I select for Mrs. Miggins, and then hang because Miss Marple's updates are pending. At least I could tell Mrs. Miggins that I couldn't tell her the stock state.

One sale lost, I think.

Regards
HJR
> David
>
> (rm ns beside @ in return email address)
>
> On Thu, 4 Dec 2003 05:59:46 +1100, "Howard J. Rogers"
> <hjr_at_dizwell.com> wrote:
>
> >
> >Time to don the Devil's Advocate costume, I think.
> >
> >I can think of lots of cases where it would be rather unfortuate to see
an
> >old piece of data just prior to it being changed. Rather than see the old
> >data, I could well imagine that it would be more helpful to see nothing
> >until the situation stabilises.
> >
> >If I have a customer demanding to know whether I have a turbo-widget in
> >stock, I can select from my products table to check. It tells me I have
one
> >such item left. Mrs. Miggens therefore, on the strength of that,
undertakes
> >the arduous two-hour journey from remote rural New South Wales into the
City
> >Centre to pick up said turbo-widget. Unbeknownst to her, however, the
> >information I gave her was wrong, because at the time I did my query,
Fred
> >in the next cubicle was selling the same product to Miss Marple. He
hadn't
> >committed the transaction, which is why I saw a stock level of 1. But it
> >would have been nice not to give the wrong info out to Mrs. Miggens. I
> >suppose I could have badgered her into placing an order, because then my
> >attempt to update the stock level myself would have failed. But Mrs.
Miggens
> >ran into a bit of credit rating trouble a while back, and doesn't have a
> >credit card. The most she can do on the phone is to enquire.
> >
> >There are two choices there, I suppose: see nothing at all (the blocking
> >idea). Or see a stock level of 0 (the dirty reads issue beloved of, er,
> >certain other products). Oracle's long-time answer has been: you'll see
1,
> >and only 1, and nothing else, ever... which some might consider to be a
lack
> >of choice in answering technology.
> >
> >Regards
> >HJR
> >
> >
> >
> >
>
Received on Wed Dec 03 2003 - 22:01:34 CST