Andy Hayler on Federated Data Warehousing

May 29th, 2006 by Mark Rittman

Apart from a

talent for producing criminal geniuses
, the UK seems to be good at producing
data warehousing experts, and Kalido’s Andy Hayler is one of my favourites. His
blog is always a good read, and I particularly enjoyed a couple of his recent
posts, on

data warehouse architectures
, and the

business payoff of a data warehouse project
.

The data warehouse architectures posting is particularly well timed as it
looks at the inevitability of federated data warehouse architectures, something
that’s now possible with an all-Oracle setup when you use the new Siebel
Analytics-derived BI Suite. Up until now, the mantra from Redwood Shores has
been to build a single, consolidated data warehouse for the entire enterprise,
but in Andy’s opinion, this is never going to happen due to the sheer scale of
the undertaking, and in his opinion:

"… for any large corporation it seems to me that a federated
warehouse approach is what you will end up with, whether you like it or not.
Few companies will have the energy or resources to deliver the single giant
warehouse, and even those few that do will, in reality, have a series of
skunk works data marts/warehouses dotted around the corporation since such a
behemoth warehouse will be a bottleneck, hard to change and inevitably slow
to respond to rapidly changing business needs.

The most pragmatic approach would seem to me to acknowledge this reality and
architect for a federated approach, rather than staying in denial. It is
practical to build a warehouse for either a country-level subsidiary (or
groups of countries) or each business line, let that deal with the needs of
that particular country or business line, and then link these together to a
global warehouse which deals at the summary level. The global warehouse does
not need to store every transaction in the enterprise; at that level you
need to know what the sales were in Germany yesterday by product, channel
and perhaps customer, but not that a particular customer bought a specific
item at 14:25 at a store in Rhine-Westphalia. The detailed information like
this is the domain of the country-level warehouse. Because the transaction
detail is not needed at the enterprise level, you avoid the problems of
technical scale that may otherwise occur, and only deal with the data that
makes sense to look at across the enterprise as a whole."

The second posting, entitled "Putting a little glitz into data warehousing",
looks at how data warehouses are rarely the first thing you think about building
after an acquisition, and yet they can be a perfect way to start delivering
synergistic cost savings fairly soon after the merger.

"For example, when HBOS merged, one of the key areas for quick savings
was identified as procurement. Yet to just pick one of the existing
procurement systems, switch off the other and convert all the data from one
to the other was estimated at taking well over a year. Instead, what they
did was to implement a packaged data warehouse, map the two sets of data
from each bank, and in this way get a single view of the procurement spend
across torganizationion without having to convert all the data in the
underlying systems. This was achieved in just three months, giving an
immediate view of post-merger procurement that allowed huge business savings
to achieved. For more on this award-winning project click

here
."

A pretty interesting couple of postings, and there’s another one

here
about explaining Master Data Management to a business audience. Andy
Hayler’s got a wise, experienced perspective on data warehousing and you’d do
well to bookmark his blog if you’re interested in the subject.

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