Postgres LISTEN/NOTIFY does not scale

Right, plus there's character limitations (column size). This is why I prefer listening to the Postgres WAL for database changes:

https://github.com/cpursley/walex?tab=readme-ov-file#walex (there's a few useful links in here)

I found recently that you can write directly to the WAL with transactional guarantees, without writing to an actual table. This sounds like it would be amazing for queue/outbox purposes, as the normal approaches of actually inserting data in a table cause a lot of resource usage (autovacuum is a major concern for these use cases).

Can’t find the function that does that, and I’ve not seen it used in the wild yet, idk if there’s gotchas

Edit: found it, it’s pg_logical_emit_message

pg_logical_emit_message() is how I recommend users on Postgres to implement the outbox pattern [1]. No table overhead as you say, no need for housekeeping, etc. It has some other cool applications, e.g. providing application-specific metadata for CDC streams or transactional logging, wrote about it at [2] a while ago. Another one is making sure replication slots can advance also if there's no traffic in the database they monitor [3].

[1] https://speakerdeck.com/gunnarmorling/ins-and-outs-of-the-ou...

[2] https://www.infoq.com/articles/wonders-of-postgres-logical-d...

[3] https://www.morling.dev/blog/mastering-postgres-replication-...

You know, this would be a great talk at the 2026 Carolina Code Conference...