Comment by tsmarsh
3 years ago
'over the wire' is less obvious than it used to be.
If you're in k8s pod, those calls are really kernel calls. Sure you're serializing and process switching where you could be just making a method call, but we had to do something.
I'm seeing less 'balls of mud' with microservices. Thats not zero balls of mud. But its not a given for almost every code base I wander into.
To clarify, I think stateless microservices are good. It's when you have too many DBs (and sometimes too many queues) that you run into problems.
A single instance of PostgreSQL is, in most situations, almost miraculously effective at coordinating concurrent and parallel state mutations. To me that's one of the most important characteristic of an RDBMS. Storing data is a simpler secondary problem. Managing concurrency is the hard problem that I need most help with from my DB and having a monolithic DB enables the coordination of everything else including stateless peripheral services without resulting in race conditions, conflicts or data corruption.
SQL is the most popular mostly functional language. This might be because managing persistent state and keeping data organized and low entropy, is where you get the most benefit from using a functional approach that doesn't add more state. This adds to the effectiveness of using a single transactional DB.
I must admit that even distributed DBs, like Cockroach and Yugabyte have recognized this and use the PostgreSQL syntax and protocol. This is good though, it means that if you really need to scale beyond PostgreSQL, you have PostgreSQL compatible options.
> I'm seeing less 'balls of mud' with microservices.
The parallel to "balls of mud" with microservices is tiny services that seem almost devoid of any business logic and all the actual business logic is encapsulated in the calls between different services, lambda functions, and so on.
That's quite nightmarish from a maintenance perspective too, because now it's almost impossible to look at the system from the outside and understand what it's doing. It also means that conventional tooling can't help you anymore: you don't get compiler errors if your lambda function calls an endpoint that doesn't exist anymore.
Big balls of mud are horrible (I'm currently working with a big ball of mud monolith, I know what I'm talking about), but you can create a different kind of mess with microservices too. Then there all the other problems, such as operational complexity, or "I now need to update log4j across 30 services".
In the end, a well-engineered system needs disciple and architectural skills, as well as a healthy engineering culture where tech debt can be paid off, regardless of whether it's a monolith, a microservice architecture or something in between.
> I'm seeing less 'balls of mud' with microservices. Thats not zero balls of mud.
They are probably younger. Give them time :P