Re: "Transactions are bad, real bad" - discuss

"Mikito Harakiri" <mikharakiri_at_ywho.com> wrote in message news:iZysa.12$rv3.138_at_news.oracle.com...
> "Paul Vernon" <paul.vernon_at_ukk.ibmm.comm> wrote in message
> news:b8to09$2178$1_at_gazette.almaden.ibm.com...
>
> > 12:15 is some arbitrary time after the auction closes and after the row
> was
> > committed.
>
> OK. For the auction closed at 12:00 organizer wants to query at 12:15 (or
> any time for that matter) and to know what bids were comitted before 12:00.
>
> > Maybe you need to try it in your favourite DBMS. I don't have Oracle, so
> can
> > only simulate it's AS OF function:
>
> The problem is that "flashback" uses history log that is recording *all* the
> events, even for transactions that were rollbacked.

So with "flashback" you see uncommitted rows???

> If you try simulating
> this with triggers, a user can still rollback transaction so that the record
> would be lost. Then, no wonder that you can't reproduce a consistent picture
> what Bid Auction state was as of 12:00.

I don't think I follow you, but if I do you are saying that uncommitted transactions should be part of the 'consistent picture' as at 12:00 ??!!

> I think you have to use autonomous transaction inside the trigger in order
> to correctly simulate "flashback".

I've no idea what a 'autonomous transaction' is. Oracle specific thingamajig?

> > Practically, I cannot use a 'flashback' query if I want to know say the
> > average max bid for auctions during the past year. In your scheme I would
> have
> > to query each auction row AS AT the end time of each auction, and only
> then do
> > my yearly average calculation...
>
> That is easy: AS OF state can simply be archieved to the other table.

What 'other table'? What would it look like? It the archive instatanous?

Mikito, if you belie that you do have a valid point here, could I ask you kindly to restate it in logical terms and not in terms of Oracle quirks and features.

Regards
Paul Vernon
Business Intelligence, IBM Global Services Received on Tue May 06 2003 - 19:16:05 CEST