Almost every web app. Exceptions are stuff like dynamic map tile generation. Even WhatsApp scale runs on a “slow” dynamic language.
> Almost every web app.
No? My point is exactly that almost every web app is not io bound. They're just... slow. They write bad queries, they make bad usage of resources and block on requests, etc.
> Even WhatsApp scale runs on a “slow” dynamic language.
But that has nothing to do with being IO bound. Whatsapp, via Erlang, works by having tons of connections on a single box. And you can watch plenty of talks by them about how they've had to work with BEAM to get Erlang to actually be IO bound.
"IO bound" is a meme. Most people just mean "my queries are slow". Unless you're saturating your NIC, you're not io bound with regards to throughput, and unless your queries execute in ~<100ns you probably aren't IO bound on latency either.
However the important point is that they aren't CPU bound either. Most are "user acquisition bound" (like tens of requests per second peak). Some are more like "developer time bound" (cutting the server farm in half is not worth the cost in dev time).
Either way, using a slow development framework (including language, DB, etc.) that the developers like is a reasonable choice for what they're trying to do. (I personally wish most software was faster, but they have no reason to care what I think.)
Maybe the terminology around this could be developed some more.
4G latency 50ms
AWS inter AZ latency 1ms
Thread context switch 2us
The response times from things like search APIs even at FANG companies with vast resources and highly skilled engineers are often in the hundreds of milliseconds.