PolarDB-for-PostgreSQL VS walex

Disaggregated storage for Postgres is still a very new technology, both with NeonDB and PolarDB (https://github.com/ApsaraDB/PolarDB-for-PostgreSQL).

Amazing work by the Team. Congrats y'all. It was one of the best presentations in the PGcon22.

I did email Heikki the following questions, in case if someone from Neon is around here.

a) How does Neon compare to polardb https://github.com/ApsaraDB/PolarDB-for-PostgreSQL.

b) The readme mentions a component "Repository - Neon storage implementation". Does it use any special FileSystem? Any links to read more about it?

c) Heard the cold start is a second (IIRC), how does that value differ if one runs Neon on bare metal instead of k8s?

【Reference - Documentation】 https://github.com/alibaba/PolarDB-for-PostgreSQL#contributing

【GitHub - PolarDB for PostgreSQL】 Check Now >

PolarDB, yet another open source database system based on PostgreSQL\ (41 comments)

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

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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).