PostgreSQL conditional upserts

So in order to do an "upsert" we use an INSERT command with a CONFLICT statement. Then if we need to do some conditional setting in the case of existing data then we can use the "temp table" EXCLUDED that PostgreSQL provide to us. They have a nice example how to use that in their docs and here's mine example:

implementation d’une hashchain in sqlite

The Unreasonable Effectiveness of SKIP LOCKED in PostgreSQL

Using SKIP LOCKED to distribute work across machines in a distributed system is a popular pattern. We explore why, the alternatives, and a real world example from our own codebase.
Nadeesha Cabral on 17-12-2024

When building distributed systems that need to process jobs or tasks concurrently, one of the most challenging problems is ensuring that work is distributed efficiently without duplication. PostgreSQL's SELECT FOR UPDATE SKIP LOCKED feature provides an elegant and performant solution to this problem that almost feels too good to be true. We're big believers in the just use postgres ethos, as our source code might tell you.