[marcosdumay]

> But distributed systems is a well understood thing in the industry.

Wait, what?

Distributed systems are one of the most active areas on CS currently. That's the opposite of "well understood".

It's true that most systems people create are required to be distributed. But they are coordinated by a single database layer that satisfies approximately all the requirements. What remains is an atomic facade that developers can write as if their clients were the only one. There is a huge difference between that and a microservices architecture.

[NationalPark]

Distributed systems are well understood though. We have a lot of really useful theoretical primitives, and a bunch of examples of why implementing them is hard. It doesn't make the problems easier, but it's an area that as you say, has a ton of active research. Most engineers writing web applications aren't breaking new ground in distributed systems - they're using their judgement to choose among tradeoffs.

[marcosdumay]

Well understood areas do not have a lot of active research. Research aims exactly to understand things better, and people always try to focus it on areas where there are many things to understand better.

Failure modes in distributed systems are understood reasonably well, but solving those failures is not, and the theoretical primitives are way far from universal at this point. (And yes, hard too, where "hard" means more "generalize badly" than hard to implement, as the later can be solved by reusing libraries.)

The problem is that once you distribute your data into microservices, the distance from well researched, solved ground and unexplored ground that even researchers don't dare go is extremely thin and many developers don't know how to tell the difference.

[bulleyashah]

Correct. That doesn't make monolithic systems "not distributed".

Secondly, I don't know why you say "distributed systems are an active area of research" and use this as some sort of retort.

If I say "Is a monolithic app running on two separate hosts a distributed system or not", if your answer is "We don't know, it's an active area of research" or "It's not. Only microservices are distributed"

[marcosdumay]

Hum... I don't think you understood what I said.

Most of what people call monolithic systems are indeed distributed. There are usually explicit requirements for them to be distributed, so it's not up to the developer.

But ACID databases provide an island of well understood behavior on the hostile area of distributed systems, and most of those programs can do with just an ACID database and no further communication. (Now, whether your database is really ACID is another can of worms.)