[melozo]

I worked at <large tech company everyone hates> and we had this exact architecture. The senior engineer (who went to Stanford and was proud of it) designed this system. I had long arguments with him about how this system wouldn't scale when we launched it, and used real production data to prove that it would happen. No one listened to me, it launched and imploded within a few weeks, and soon after I transferred off the team. The worst part is, that senior engineer was eventually promoted and that system was passed off to an entirely new team to battle with. That entire system was terribly designed, and I think you can guess why.

[beachy]

Show me your tables, and I won't usually need your flowchart; it'll be obvious." -- Fred Brooks, The Mythical Man Month (1975)

It astonished me that people can ever think this is a good idea (everything in a single json document) or that anyone who thought it was could ever get funding or even get through any basic customer due diligence.

[cess11]

One part of my work entails entering companies on their death bed and going through their software development and related investments. I see a lot of JSON-storage in the initially well funded ones. They cough up some crap on Firebase, get some tens of millions of dollars in venture funding, burn through, and never leave Firebase.

It's really, really hard to sell systems implemented with these sexylicious clown technologies. Like, extremely hard. Apparently no sane person with money wants to pay a non-trivial amount for a pile of locked in JSON and Python scripts, and I haven't managed to add any insane ones to my network yet.

The small companies without funding that topple over and end up in my way, more commonly they instead put some stuff on a VPS or two, and typically the market values them quite a bit higher.

Fashionable technology choices burn through a lot of investment money. Seems to me like maybe a sign that money has been a bit too cheap a bit too long.

[jerf]

It works great at a small scale. It's really convenient to have all the data at hand and be able to manipulate it directly in your programming language without having to go through SQL, which, no matter how comfortable you may get with it over years of experience and/or no matter how much library/ORM/etc. you throw at it, is always a foreign imposition into your programming language.

If you know beyond a shadow of a doubt that you will never leave "small scale", it's honestly not a terrible approach. It's also easy to define how to backup "the one file that is everything". You also ought to be confident that the worst case of the One File becoming corrupted is something you can deal with. (Although this is an often-overlooked issue in systems design anyhow.)

I've got some systems that have bits and pieces of this idea... but I'm really, really confident they'll never scale any bigger because for the systems in question it's simply impossible they ever would. I've got one that is, for instance, bounded on the set of wiki pages of a certain type that for it to grow into the 10,000s of pages where the approach would finally start to creak (from the "dozens" it has been in for the last several years and to all appearances will remain indefinitely) would require so much human effort to create those 10,000s of pages that I'd certainly have the budget to upgrade the approach anyhow as it would be negligible compared to the rest of the effort.

It also helps if this not something you're loading per HTTP request; in my case it's one-time on startup of a persistent service.

But you need to know you understand the relevant scales, because this is an immense trap if you don't do the math (it's not hard math, but it's math). Your prototypes work well and are easy to write and then are just total trash when they go to production, and presumably, if the engineer didn't do the math in the first place, it will emerge that they don't understand why the system is crashing in production either. Huge, huge trap. I've not quite seen this exact one with JSON files but I've definitely witnessed the "prototype that any experienced engineer could have absolutely guaranteed would not scale in about 5 minutes of examination".