On Thu, 2020-08-27 at 10:10 +0530, Hemil Ruparel wrote: > I was playing with Advisory locks. I opened three connections to the database And obtained > a lock with the same key. I noticed that the locks were obtained in the order of requests. > I was wondering whether the locks are guaranteed to be First Come First Serve and can this > behaviour be relied upon.
Yes - lock requests that block are queued, with later lock requests queued behind previous ones. Once a lock gets free, the first in line gets it.
This is the same for all heavyweight locks in PostgreSQL.
