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

SQLJoe wrote:

> HJR wrote:
>
> >Well, I'm afraid it is true. Read Niall's post.... he demonstrates the very
> >fact I'm talking about. The reading session hangs because someone is
> >updating the row.
>
> I was going to respond to nail's post but I got disconnected. Let me respond
> now..
>
> AGAIN, you can read a row that is being updated in MS SQL using a read
> uncomitted isolation level.
>
> In the sesion 2 in his example, you can use the following
>
> use northwind
> select "query" with (readuncomitted)
>
> Here is the Microsoft's documentation on read uncomitted isolation level.
>
> READ UNCOMMITTED
>
> Implements dirty read, or isolation level 0 locking, which means that no shared
> locks are issued and no exclusive locks are honored. When this option is set,
> it is possible to read uncommitted or dirty data; values in the data can be
> changed and rows can appear or disappear in the data set before the end of the
> transaction. This option has the same effect as setting NOLOCK on all tables in
> all SELECT statements in a transaction. This is the least restrictive of the
> four isolation levels.
>
> >So what? That's wasn't the point. The point was, if a transaction runs for
> >too long in SQL Server, such that it uses up more than half the transaction
> >log, it fails, and rolls back. And that's because a transaction needs as
> >much room in the transaction log to roll back as it needed to be rolled
> >forward in the first place. Rollback and redo are combined into a single
> >mechanism, which gives rise to this problem (and SQL Server isn't the only
> >database to suffer this way). Oracle doesn't give a monkey's how long a
> >transaction runs for, because redo and rollback are entirely separate
> >mechanisms.
>
> I think you are too stuck in your Oracle mind. The fact is MS SQL beats Oracle
> in performance. Here is the link if you want to know the truth.
>
> http://www.tpc.org/tpcw/results/tpcw_perf_results.asp
>
> I think it is sad you are still in denial. But that is your loss
>
> Jinsoo

READ UNCOMMITED is one thing.
Multiversioning another.
Multiversioning has nothing to do with reading uncommited data. There is no relationship between them just as there is no relationship between this thread and any real technical issue that anyone cares about. The sum of this thread is "Two different products doing things in different ways". If you are going to use the product ... use it appropriately.
Lets kill the thread.

Daniel Morgan Received on Thu May 23 2002 - 10:16:11 CDT