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

From: DA Morgan <>
Date: Fri, 08 Feb 2008 21:22:42 -0800
Message-ID: <>

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 Group
Received on Fri Feb 08 2008 - 23:22:42 CST

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