[rand_r]

Yes, exactly! We found out the hard way just how unreliable Redis-based locks are, and switched to Postgres locks. It works reliably since our code is already in a Postgres transaction.

Created a “lock” table with a single string key column, so you can “select key for update” on an arbitrary string key (similar UX to redis lock). I looked at advisory locks, but they don’t work when the lock key needs to be dynamically generated.

[quectophoton]

After reading the current[1] top comment about Redlock, this was literally the next low-effort thing that came to mind, so I'm glad to find some else's experiences with using a PostgreSQL table as a lock.

I will need a distributed lock soon, but I've never used one before so I'm taking this chance to learn about them.

[1]: https://news.ycombinator.com/item?id=41315621