The unbearable rightness of CouchDB

As I mentioned recently, this website is built on CouchDB. CouchDB is in many ways a very innovative but still very simple database, and it has the unique quality of genuinely being a "database for the web", as the marketing copy claims. However, lately most of the time what I feel about CouchDB is not joy but more a kind of frustration at how close – how agonisingly close – it is to being amazing, while never quite getting there.

The first one that really gets me is CouchApps. They're so close to being a transformative way of writing software for the web. Code is data, data is code, so why not put it all in one big code/database? Then people can run their own copies of the code locally, have their own data, but sync it around as they choose. Years before things like unhosted or serverless webapps were even on anyone's radar, CouchDB already had a working implementation.

Well, kind of. Unfortunately CouchApps never really had first-class support in CouchDB. The process of setting one up involves making a big JSON document with all your code in it, but the admin UI was never really designed to make that easy. The rewriting engine (what in a conventional web framework you might call a router) is hilariously primitive, so there certain kinds of structures your app just can't have, and auth is a total disaster too. The end result is that most of the time you need to tack some extra auth/rewriting proxy service on the front of your gloriously pure CouchApp. What a waste.

There are other similarly frustrating missed opportunities too. CouchDB had a live changes feed long before "streaming is the new REST" realtime databases like Firebase showed up, but never went as far as a full streaming API or Redis-style pub/sub. It has a great inbuilt versioning model that it uses for concurrency, which could have meant you magically get versioned data for free – but didn't. It has a clever master-master replication system that somehow doesn't result in being able to generate indexes in parallel.

I should say that, although it frustrates me to no end, I really do respect CouchDB. At the time it came out, there were no other real NoSQL databases and a lot of the ones that have come since went in a very different direction. Compared to them, I admire CouchDB's purity and the way its vision matches the essential design of the web. But in a way I think that's exactly what makes it so frustrating. That vision is so clearly written in the DNA of CouchDB, and it's such an amazing, grandiose vision, but the execution just doesn't live up to it.