walex VS electric

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).

I'm interested in this problem also!

I think there is a large overlap with projects that market/focus on offline-first experiences.

AFAIK this problem can be solved by:

1) Considering a client-side copy of the database that gets synced with the remote DB. This is an approach [PowerSync](https://www.powersync.com/) and [ElectricSql](https://electric-sql.com/) and [rxdb](https://rxdb.info/) take!

Yeah I agree with it being an exaggeration. They are certainly riding the admittedly dated perception that realtime is so hard it's only available to the Googles and Figmas. But there's now some amazing open source solutions available like Y.js and ElectricSQL[1]. The barrier has certainly come down.

[1] https://github.com/electric-sql/electric

https://github.com/electric-sql/electric :

> ElectricSQL is a local-first software platform that makes it easy to develop high-quality, modern apps with instant reactivity, realtime multi-user collaboration and conflict-free offline support.

> Local-first is a new development paradigm where your app code talks directly to an embedded local database and data syncs in the background via active-active database replication. Because the app code talks directly to a local database, apps feel instant. Because data syncs in the background via active-active replication it naturally supports multi-user collaboration and conflict-free offline

"SQLedge: Replicate Postgres to SQLite on the Edge" (2023)

Yup, this is correct.

We have had some requests / discussions around adding hooks to the sync service that will support custom logic on the write path (as per https://github.com/electric-sql/electric/discussions/565). This seems like a good idea but they don't exist yet.