One Billion Cells – Another Multiplayer Demo with Clojure
cells.andersmurphy.com
cells.andersmurphy.com
Happy to answer any questions.
The scaling was preemptive as it was hitting 150% CPU (out of 200%). Needed to power down to rescale.
Now it's hovering at around 200% (out of 400%). About 80kb/s and 10 disk iops.
Everything goes via a sqlite db.
But because it's sqlite it's a single writer. Everything gets batched as one transaction every 100ms. The operations on a single chunk gets squashed into a single write.
Even without the squashing sqlite can handle 10000-20000+ updates/s because of the transaction batching.
With the chunk based squashing all edits to a chunk in that 100ms window become one update, so it can scale quite well.
Btw, if I add a ' to the string, it's impossible to override by othrs. At least in the UI on Firefox, the snake still ate it.
I'm planning on doing a write up on th se billion-foo style games at some point. It's been a fantastic learning experience.
I put this together in a day and wasn't planning on it being on HN. So there's definitely some jank/UX polish.
For example the typing experience is nicer on chrome as the field sizes to the text.
Or played Doom, for that matter.
There's a bad apple demo on the datastar site. Datastar's[1] streaming hypermedia is what makes this possible, that and good old Clojure and sqlite.
Once everything clicks it becomes a force multiplier and a joy to work with, something that helped me in that regard is throwing a "data-json-signals" on an element so its easier to keep an eye on things.