Show me an autosharding solution for an open source SQL database that doesn't involve paying tons of money. Until then I'm not convinced I should ditch MongoDB.
So how is there no room for NoSQL databases? I understand that most sites running NoSQL at the moment could just as well (or even better) run on Postgresql, even with 'biggish data', but is for 'enormous' data and near real time analysis of it, NoSQL not a proper solution over 'traditional' RDBMSs. Not trolling; really curious what people have to say.
Do I understand it correctly that Oracle 'Exadata' just uses fiber cables and such to threat the entire rack as 'one node' or does it work differently? How does Oracle scale? Any information about that (tech information, not opinions/interpretations of reality as OP posted)?
Just go with both. MongoDB can't make your data live & evolve the way an RDBMS can. You can't inject intelligence in your noSQL database, but you can sure extract data, a lot of it, a ton of it, with as many concurrent clients you wish. If you can't find a use for a relational model in any project, then I'm not sure what to say. But if you can, maybe try a postgres & Mongo combo for the best of both worlds?