Database denormalization on internet-scale sites

Arnon Rotem-Gal-Oz as posted about database denormalization on internet-scale sites (such as Amazon, eBay, Flickr , etc...).

The A&D 2007 : The eBay Architecture (Randy Shoup & Dan Pritchett) is triggering the discussion.

Examples of the denormalization:

• disabling transactions;
• denormalizing data;
• [not circumscripted do DB] SOAing the operations by business classes;

Data denormalization is not news to us - I remember back in college to learn to normalize to the Nth Codd normal form, and then to denormalise if necessary. The fact that 3-tier arquitectures doesn't guarantee scalability is not news either. What really impresses me is the option to drop ACID transactions.