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Re: Db2, Oracle, SQL Server

From: Serge Rielau <>
Date: Tue, 08 Feb 2005 08:47:52 -0500
Message-ID: <>

Noons wrote:
> Serge Rielau wrote:
> If IBM really truly wants to criticize the locking mechanism
> of Oracle (and I'm the first one to say it should do so),
> then it is quite fitting that you folks LEARN what it is all about.
> And Steve's book is the only reference out there that completely
> explains all those things.
> You may take the pedantic approach of ignoring it, but it will
> be at the cost of credibility of any IBM criticism, believe me.
Noons, where is IBM critizing multi-version read consistency? Speaking for myself (which is all I can do) please point me to where I use the words "better" or "worse"? There is no such thing as a free lunch however, and that is what is often forgotten by some posters. And if pointing that out is criticism, I'll carry that burden.

> I find no downsides in Oracle's row locking. Multi-versioning may have
> some, but that is separate from true row locking. Of course, you
> may think that a mechanism that implies and needs lock escalation
> is superior. I don't think so and there are a lot of people
> out there who share my opinion.

I don't think it's superior. I don't think it's inferior either. It's price-worthy. As technology moves on downsides on either side get worked on. DB2 from release to release get's more subtle about locking while Oracle is reliefing the burden of managing rollback segments.

>>Isn't it ironic that if SQL Server 2005 ever ships it will be the

> only
>>mainstream DBMS supporting all major isolation levels?

> At what cost, though. And: are they really needed?
> And: isolation levels are not exactly the same as update locks.
> Too many imponderables. But yes, it is ironic.
Correct, locking is the means to the end of isolation level. It is isolation level that an App developer designs for and it is locking that a developer works around ;-) Apparently the industry believes they are all needed, including multi version.

> There is one thing about SS that is truly endearing it to me:
> its ability to use any language for SPs.
CLR? You mean DB2 UDB V8.2 for LUW then, available since , uh 1/2 year. SQL Server 2000 does not do that and let's talk about SQL Server 2005 when it ships.
Hard to believe you falling for MS vapor ware ;-)

 > Not just T-SQL.
> That is a great idea and it should be adopted by others.
> And before anyone mentions the bleeding obvious: no, Java is a
> piss-poor language for data manipulation and I hate having to
> be stuck with it in Oracle if I want to use aything else than PL/SQL.


Serge Rielau
DB2 SQL Compiler Development
IBM Toronto Lab
Received on Tue Feb 08 2005 - 07:47:52 CST

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