I know noSQL is all the rage with the crazy kids these days and I know it has its place but why is half of the literature regarding noSQL about solving problems that are trivial in an RDBMS?
There's a legitimate rant to be had about using elephant architecture to serve mouse traffic, and I think that's what annoys me most about the NoSQL fad. But that doesn't mean the problems mentioned in this article don't exist.
I'm not sure I understand. If I make an application that has to increment a counter, shouldn't I always be worried about concurrency?
What I mean is, sure, if I'm serving only a few requests, then of course the probability of running into concurrency issues is lower than a site with more requests/sec. But it's still a matter of chance, there is some probability that two requests will come in at exactly the same time and cause a problem.
The parent poster is worrying about performance of concurrency. This doesn't need to be worried about unless you are one of about 5-10 tech companies whose name is recognisable to people on the street.
I think people really overestimate their data-store needs, and underestimate how much a big iron DB server can deliver.
Its probably worth thinking about scaling out on your data end, but until you start hitting some sort of limit on a 8 core 96 gig machine with server level SSD's its probably worth investing your time in other issues.
But, if you've built a site on the precondition that one database is enough, with a lot of joins so you can't split tables, and your hardware can't keep up.. you're in a really bad place. I say this out of experience ;)
Of course over a certain scale this is normal, so im not interested in a site with 50 millions users, but cases where a single DB is not the best solution.
Since these queries were built over ~10 years with the expectation of being able to join any of the thousands of tables, it would now be a tremendous undertaking to perform any sort of sharding or other ways of distributing load (other than master-slave replication, which was used widely).
It's been a struggle to keep hardware up to pace with the desired growth of the company. Even with a dedicated data center and top of the line hardware, doubling their user base would probably require a significant architectural undertaking.
Had the site been designed to support an arbitrary amount of distributed database servers from day one, it would now be trivial to grow horizontally.