Ever wondered why those routers at your ISP don't have harddisks in them?
Anyways, you lost me the moment you mentioned twitter in a line with banking and telco systems. That's like bringing up the bobbycar in a discussion about jet engines.
*(sorry the reply button wasnt under your comment before)
just because they dont have harddisks doesnt mean they dont run a database, remember when I said databases dont need to touch the disk.
mnesia for example was built with exactly high throughput in mind, it can sit in memory only, I do believe mnesia is used inside various routers and switches, is it not a database?
and wow, twitter isnt cool so I guess my argument sucks, the point was different people have wildly varying requirements, and while we are talking about apples vs orange, a web chat vs a router, really?
"x isnt fast enough", "y isnt scalable enough" are inane statements, there isnt enough information to possibly make that distinction, as I said in my first post, if a database gives me extra functionality while satisfying every other of my constraints, its by definition "not doing it wrong"
repeating myself again, but we were arguing a hypothetical specification and the general statement "but using a DB for chat is a really bad idea."
that aside, the authors requirements for the application were pretty obviously to build something kinda fun using couchdb, he satisfied those requirement, and is obviously not "doing it wrong"
but next time you get into a discussion / argument like this, its usually a good idea to look at all points that have contradicted what you have just said, and say why they are wrong, or admit you were wrong.
saying twitter is not cool, some guys 100 lines of code isnt replacing irc tomorrow, or that routers arent using mysql are not arguments.
You were arguing for the sake of the argument, that's why I ignored most of your bullets as unrelated. You broadened the scope to "but what if his chat system needs to record all messages, brew coffee and babysit my dog, too"? Well in that case, yes, you'll need a database and lots of other things, too.
But as long as you're looking at a chat system with functionality like the one the original submitter presented, then there are good reasons for datastores (aka databases) and message brokers to remain separate entities.
I can only repeat: Twitter is not cool (it's an anti-pattern), people who don't understand IRC will keep reinventing it poorly, and a messaging system that hits the disk for each individual message needlessly (i.e. without being held to strong delivery guarantee requirements, which would be quite uncommon for a chat-system) is a waste of ressources.
We can't stop people from peeling their eyes out with forks, but we should at least refrain from defending such idiocy.
Anyways, you lost me the moment you mentioned twitter in a line with banking and telco systems. That's like bringing up the bobbycar in a discussion about jet engines.