I suggest you go look at https://www.postgresql.org/docs/9.4/explicit-locking.html https://www.postgresql.org/docs/9.4/explicit-locking.html. TLDR as you didn'

I suggest you go look at https://www.postgresql.org/docs/9.4/explicit-locking.html https://www.postgresql.org/docs/9.4/explicit-locking.html. TLDR as you didn't even bother to Google: Allows you to create application defined locks. Useful for building job queues and other systems where row locks aren't ideal.