I went down this rabbithole once, and turns out you /can/ do something like this, having everything streaming all the way from the database to python to the web server to the client. The problem then was that even after all that effort, whatever javascript usually was processing that in a non-streaming way.

Then I found this http://oboejs.com/ and it was even more work, and I gave up. In the end it required rethinking everything and battling against a whole set of tools and libraries that just didn't think that way.