r2dbc-postgresql VS walex

Now that we have an application, let's turn it into a reactive application. For this, we will replace Spring Web dependency with Spring WebFlux, Spring Data JPA with Spring Data R2DBC. We will also add R2DBC dependency for our H2 database. R2DBC works with a reactive driver so it will integrate nicely with the rest of our application to allow us database access in a non-blocking way.

However, if you really expect a lot of users (especially concurrent ones) to use your API, you should delve into the world of reactive programming. Use tools like RxJS (JS/TS) or Project Reactor (Java) in such a case, preferably in combination with a broker like Kafka or RabbitMQ. R2DBC is also great for a data store. Then of course if you want to go one step further, there also exists the less popular but very interesting Actor model which Akka easily has ported into Java.

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).