Re: Convert SAP Oracle Database to IBM DB2 Database??

From: DA Morgan <>
Date: Fri, 08 Feb 2008 22:43:28 -0800
Message-ID: <> wrote:

> On Feb 9, 12:22 am, DA Morgan <> wrote:

>> Mark Townsend wrote:
>>>> The compression dictionary is part of the table's meta-data, thus it
>>>> is cached.
>>> At some stage this is going to hit a memory limit, as more data and more
>>> tables are compressed.
>>> > If data values are highly localized, then having local
>>>> dictionaries can be helpful.
>>> That IS the crux of the matter. We think most data is indeed localized,
>>> I would be surprised, and willing to discuss over a beer, if IBM thought
>>> differently.
>>> BTW - that is why random data generation does not show compression of
>>> well in Oracle.
>> The fact that it achieves as high a compression as it does is actually
>> quite impressive which was the point of my demo.
>>>>> No matter how you do it, to get back to the original point of the
>>>>> thread, it is a lousy reason to consider changing the back-end from
>>>>> product A to product B given what I've seen of both.
>>>> I don't think it is a lousy reason. It is an insufficient reason in
>>>> isolation.
>>> And interesting enough, the whole conversation has been largely
>>> irrelevant. The real question to ask - given product A and product B,
>>> under SAP, which database takes more space to store the same amount of
>>> data ? Firstly uncompressed, and then compressed. The answer is freely
>>> available to anyone with a SAP support contract.
>> Though I still think that far less important to management than the size
>> of the pool of potential employees that can manage that infrastructure
>> not just today but 5+ years from now when the current crop of gray-hair
>> no-hair DBAs hit retirement age.
>> --
>> Daniel A. Morgan
>> Oracle Ace Director & Instructor
>> University of Washington
>> (replace x with u to respond)
>> Puget Sound Oracle Users Hide quoted text -
>> - Show quoted text -
> My company is mingrating  fromDB2 to Oracle for SAP because there are
> many morep eople who know Oracle than DB2. SAP was developed to be
> "database independent",but I  read they provide  libraries  of their
> databse code
> optimized for Oracle as well. Therearemany  implementaions of SAP
> using Oracle. I doubut decision for choosing BD2 vs Oracle iseverbased
> on compression or one ortwo fetaures.

That's the point I've been making but IBM is deaf.

The truth is that the mainframe dinosaurs, a tribe too which I once belonged is aging itself out of the workforce. My years of experience with punch cards, mag tape, Fortran and COBOL puts me only a single decade ahead of the DB2 crowd which will begin retiring in droves during this decade. No one cares about 360s, 370s, Amdahl 470s, or greenbar.

There are no schools that teach DB2, no universities, no colleges, no trade schools, etc. And if you offered a DB2 class at the university where I teach the only person in the room on the first day of class would be the instructor. DB2 will become extinct because the last practitioner will be in a walker or wheelchair ... not because of a compression algorithm.

Daniel A. Morgan
Oracle Ace Director & Instructor
University of Washington (replace x with u to respond)
Puget Sound Oracle Users Group
Received on Sat Feb 09 2008 - 00:43:28 CST

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