Paul Jungwirth <pj@xxxxxxxxxxxxxxxxxxxxxxxx> writes: > I noticed that Postgres takes an AccessExclusiveLock (a lock on the > whole table) against the *referenced* table when dropping a foreign key. Yeah, that's because it involves removing a trigger. Adding a trigger used to require AEL as well, but it was successfully argued that that end of things could use a weaker lock. I find the reasoning rather dubious myself. regards, tom lane
