[onphonenow]

You can actually get pretty fancy and lightweight with listen / notify as well if desired (use select for a notify instead of endless queries)

https://www.psycopg.org/docs/advanced.html#asynchronous-noti...

[phoe-krk]

Yes, that too! I'd like to see how different Postgres techniques compare in general.

[jpgvm]

I'm not sure of anyone covering all the approaches in depth but by far the best solution is to use advisory locks. Take a look at Que, there are implementations in Ruby/Go that I'm aware of but you could easily port it to anything else as it's just a bunch of pretty simple PostgreSQL + some session features.