Sorry, I didn't mean to imply that Google or Amazon engineers implemented Cassandra (though it's notable, of course, that it was initially implemented by Facebo

Sorry, I didn't mean to imply that Google or Amazon engineers implemented Cassandra (though it's notable, of course, that it was initially implemented by Facebook, adding a third Internet behemoth to its pedigree). What I really meant to say is that it's clear that the engineers behind Cassandra have done their research and chosen an extremely well tested design, while the engineers behind MongoDB seem to be completely winging it, ignorant of the literature and writing (based on my last examination) extremely amateurish code.