[lillesvin]

I would imagine that a normal visit generates more backend traffic, given that it needs to fetch posts, thumbnails, etc. whereas a visit to a private sub wouldn't need to check more than authorization.

I could easily be wrong though, I haven't done web development for years.

[mfer]

They use a microservice architecture. Some services could scale well in servicing all those assets. What handles checking access to private subs may not.

You can’t treat the scaling as a binary feature, that it does or doesn’t

[jallen_dot_dev]

Sure, but that type of traffic is expected and they can handle it with things like caching and autoscaling. I'm suggesting that a part of the system that usually doesn't get a lot of requests wasn't designed to handle a huge influx of requests.

[bamfly]

All that other stuff's easy to cache. Authorization's cacheable, too, kinda, with some trade-offs, but they may not have bothered if it'd never been a problem before. Or this particular check my have been bypassing that caching, and it'd never cause a problem before because there weren't that many of those checks happening.

You start getting a lot more DB queries than usual, bypassing cache, the DB's remote, it's clustered or whatever, now you've got a ton more internal network traffic and open sockets, latency goes up, resources start to get exhausted...