[erinan]

The answer as often is... "it depends".

Should you run an unindexed query on every keystroke of a text input of a form for every user? No.

But if you're not a junior dev, you'll know not to do those things and you'll know to debounce the text inputs, plus maybe only query the DB is the input text is longer than n characters for example. And you'll use a GIN index at first in your Postgres DB for fast text search.

It might all sound a bit insane but I believe that everyone should give Phoenix/Liveview a try. That stack can scale and it works amazingly well even on a cheap Heroku dyno.