realtime VS walex

You can LISTEN/NOTIFY. Or you can use logical replication and a custom subscriber.[1] Supabase uses the latter.[2]

[1]: https://www.postgresql.org/docs/current/logical-replication....

[2]: https://github.com/supabase/realtime

Supabase Realtime is great for building collaborative applications. You can receive database changes over websockets, store and synchronize data about user presence, and broadcast any data to clients via "channels".

We use :telemetry to collect usage data per tenant for Supabase Realtime.

We do this for rate limiting but it also makes it very easy for us to attach a listener (https://github.com/supabase/realtime/blob/main/lib/realtime/...) which ships these (per second) aggregates to BigQuery (via Logflare), which then the billing team can aggregate further to display and actually bill people with.

Yo :D This is what Supabase Realtime does!

https://github.com/supabase/realtime

Spin up a Supabase database and then subscribe to changes with WebSockets.

You can play with it here once you have a db: https://realtime.supabase.com/inspector/new

Every project is a Postgres database, wrapped in a suite of tools like Auth, Storage, Edge Functions, Realtime and Vectors, and encompassed by API middleware and logs.

Where can I learn more about this? I've been thinking of trying to integrate Supabase Realtime (https://github.com/supabase/realtime) into my Django app (without the rest of Supabase), but I'd also like to keep things even simpler if possible.

Also, what was the reason not to go with Gevent?

I believe #2 was the main driver for the supabase team to build their real-time component: https://github.com/supabase/realtime

Background/announcement: https://supabase.com/blog/supabase-realtime-multiplayer-gene...

As a minor note, one of the linked articles talks about having used RethinkDB for its changefeeds and I made a mental note a bit back that if I ever want that supabase's realtime ( https://github.com/supabase/realtime ) provides something rather like that atop Postgres and I should try that before doing anything clever.

The WAL CDC approach: https://github.com/cpursley/walex?tab=readme-ov-file#publica...

CREATE PUBLICATION news_item FOR TABLE news WHERE (topic IS "AAPL");

What do you mean testing with processes?

I won't suggest these are the best written tests, but I test various processes, supervisors, etc like this:

https://github.com/cpursley/walex/blob/master/test/walex/sup...

You don’t send the entire WAL, just what you subscribe to - and you can even filter via SQL: https://github.com/cpursley/walex?tab=readme-ov-file#publica...

What we do is much if the business logic in Postgres. But then there’s all the other stuff like external integrations, etc.

We handled that by having an Even system built on the Postgres WAL that we use like a callback system.

I put together a little library in Elixir (that originally started out as forked Supabase realtime) for this:

https://github.com/cpursley/walex

Recently added the ability to configure WalEx to forward events to webhooks or EventRelay (so you don’t need to know Elixir).

If you're using Elixir, check out https://github.com/cpursley/walex

I've actually been thinking about turning this idea into a product where you can just point it at your postgres database and select the tables you want to listen to (with filters, like you describe). And have that forwarded to a webhook (with possibility of other protocols).

I'd love to hear folks thoughts on that (and if it would be something people would pay for).

Neat, this is the pattern I've been thinking about for a while now. Also glad to see this is Elixir based.

I've been using https://github.com/cpursley/walex (basically a fork of cainophile via a fork for subabase) to listen to Postgres changes in Elixir.

https://github.com/cpursley/walex

Which is based on WAL logs and doesnt have the same limitations.

Great writeup, just added this to the WalEx readme:

https://github.com/cpursley/walex

(WalEx is an Elixir lib for listening to the WAL and perform callback-like actions with the data)

Very cool.

I'm using Elixir to listen to change events via https://github.com/cpursley/walex (which I basically ripped off from Supabase).