Some the the databases grouped under the over-broad NoSQL umbrella have reasons to use them other than magic scaling sauce. Redis, for example, is a ridiculousl

Some the the databases grouped under the over-broad NoSQL umbrella have reasons to use them other than magic scaling sauce. Redis, for example, is a ridiculously fast in-memory database that gives you data structures like sets, lists, hash tables, strings, numbers, and so on. It's tremendously useful for some problems. For example, at Greplin we're using Redis for our document analysis pipeline. We're pushing thousands of documents through Redis every second, using it to durably hold data while it gets passed around through our various back-end worker server clusters. We've been very happy with how Redis has been performing; it handles the write-heavy workload beautifully, and is way more resistant to data loss than most systems for doing this sort of thing. We'll be even happier when it gets server-side Lua scripting in a stable release, and we can define our own commands. The point is, though, that this would be crazy to do with a traditional SQL database, or even something like Riak or CouchDB or most of the other NoSQL databases. Redis fills a different niche, and filling a lot of cool niches is what I think the NoSQL stuff should be about.