Mr Harris: When you attribute statements like
"Stonebraker said the problem with MySQL and other SQL databases is that they consume too many resources for overhead tasks (e.g., maintaining ACID compliance and handling multithreading) and relatively few on actually finding and serving data."include references to the hard proof. Pushing logic from the repository to the application does not make anything faster or slower. Cumulative work is just shuffled around. Moving logic from server to client can improve the perceived speed as you have effectively added massively to CPU and RAM capacity. So, if you have a relational data model then use SQL and a relational repository. If your data model is different then use a custom repository. The different NoSQL repositories fill this custom need. Just as, for example, FOCUS fitted the custom need for hierarchical data in the 80s! As to web scale issues, the solutions are all the same no matter how your repository models data.