When you write like this it sounds very unprofessional. Also you are basically saying "this is really expensive, unless it isn't".
Why is there any difficulty in this at all? Why would this even need to be something someone subscribes to? It is basically a nearest neighbor search.
Edit: In addition to the RAM requirements, you need a persistent volume containing the entire index attached to each serving instance, which is a real bummer when you want to scale horizontally.
> When you write like this it sounds very unprofessional. Also you are basically saying "this is really expensive, unless it isn't".
Likewise actually, it's kind of unprofessional to respond in this way to somebody's personal writing style for a writeup on her personal blog about a personal project. Go read some other Show HN thread, there's lots of genuinely cool stuff here, no need to pick on someone for writing in a way you disapprove of.
This is just as unprofessional and condescending.
edit: Looks like it is in fact against the rules, but I think I'm tentatively going to leave the comment up because I did provide a valuable answer to the parent commenter's question. Mods can do what they will of course. :)