Re: Newbie's Oracle 9i impression: it sucks

Ehem...

> Session 2
> use northwind
> go
> select top 5 orderid from big_orders
>
> session 3
> use northwind
> go
> update big_orders set orderid = orderid +1
>

session 2 comes back and updates some values in big_orders (or an other table to make things worse) using its old version of orderids. Isn't that wrong? The problem with multi versioning is that the DML always is on the current version while the data you read is on an old version. If the application didn't get coded with session 3 in mind bad things can happen here.
I wouldn't go as far as saying that any one locking scheme is right or wrong. They all have their places. But "readers don't block writers" is not better. It's just different.

Cheers
Serge

PS: I apologize for the technical content ;-)

--
Serge Rielau
DB2 UDB SQL Compiler Development
IBM Software Lab, Canada