I am actually just finishing writing an article with all the details, I will post a link as soon as it is online :) We are not using any middleware and all our

I am actually just finishing writing an article with all the details, I will post a link as soon as it is online :) We are not using any middleware and all our queries are hand-sculpted to make sure we are never causing more I/O impact than we need to. I am sure everything we do could have been done with mysql/pgsql with enough consideration for the performance characteristics of either database. Ultimately, a document-based storage was simply a better, more natural fit for us.