Re: changing the isolation level

From: Marten Lehmann <lehmannmapson_at_cnm.de>
Date: Sun, 04 Feb 2007 05:41:44 +0100
Message-ID: <52l6k2F1omvtvU1@mid.individual.net>

>> Think of a script, that generates invoices montly. Lets say you have a 
>> average volume of $1000 dollar. So if a run of the script in the next 
>> month just returns a volume of $200 you can be pretty sure, that 
>> something has gone wrong. But if you cannot see this until you 
>> confirmed all the stuff, then it is too late to revoke it.

>
> Not at all. Surely you don't think Oracle eBusiness Suite financials and
> the many banks using Oracle are overwhelmingly choosing Oracle if the
> architecture can't handle this. There are many possible solutions.

This was just an example! The point is: There are scenarious, where you need to read "dirty" uncommitted data. Don't try to think all people have just that one simple business case where everything can be managed within on transaction by one process! Think of heterogenous systems where one specialised system can change data but it cannot commit until another specialiced system reads the data and performs whatever with it.

>> Sybase supports all levels of isolation, so when I read that Oracle 
>> doesn't allow a certain isolation level it just sounds like a lame 
>> excuse for a missing feature.

>
> You are incorrect. They do not exist because they are unnecessary. You
> need to stop trying to force Oracle into your current mental model
> (Sybase-centric) and learn how Oracle works. Start with Tom Kyte's books
> and the docs at tahiti.oracle.com.

Thanks, I already own several useful Oracle books and my problem is neither a mental problem nor a Sybase one. Sybase doesn't force me to read uncommited data, it _allows_ me to do that (because I need it in my business case). And the model isn't bad because it works with Sybase. Sybase just performs perfectly according the isolation level I'm free to set, even not showing uncommited data if I want, while Oracle doesn't. Received on Sat Feb 03 2007 - 22:41:44 CST