CQRS: Command Query Responsibility Segregation

There is currently a lot of interest in the above concept, e.g. at CQRS info, which basically looks at separating database reads (queries) from writes (commands) when considering scaability and replication. A June 2012 Channel 9 video in MSDn by Grigori Melnik and Julian Dominguez included the first picture here:

In 2010, in a presentation on "A cloud database with transactions" at DB Tech, Helsinki, I included the second picture here on how Pyrrho's cloud version could do the same thing:

The really important aspect here is the convergence between the ideas involved in long-running transactions and eventual consistency with the optimistic transaction model. It offers some hope in the current nightmare world of no-transactions/no-SQL nonsense. For Pyrrho's approach see my 2010 blog post.