Re: block size

From: Michael Fontana <>
Date: Mon, 26 Oct 2009 16:02:28 -0500 (CDT)
Message-ID: <>

Niall wrote:

>so, discussion with DW architect today

>"but this isn't OLTP,this is DW, in a datawarehouse you want the biggest block size you can have".

>my question to you (and him)

>"why? What's the theory and evidence for this?"

>In other words *why* do people think this? Note I'm specifically not after pointers to religious wars (entertaining though these are) but to particular logical arguments. This chap is bright (and like me somewhat >loquacious) and I disagree with him, the resultant discussion could go on a while so I'm hoping to short circuit it.

There are numerous examples in the documentation suggesting larger blocksizes for data warehousing, including this one from Oracle:

This is not the only one, there are many examples of this recommendation in the literature on best DW practices. While it doesn't say to use the LARGEST blocksize possible, it does emphasize it's advantages in many DW scenarios, but of course, not all. no longer handcuffed. One can have multiple block sizes in the same database, which is what I've noticed in most well-tuned DW instances.

Michael Fontana

Sr. Technical Consultant

Enkitec M: 214.912.3709



Received on Mon Oct 26 2009 - 16:02:28 CDT

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