Dropping behavior for unique CONSTRAINTs

From: Conner Bean <conner(dot)bean(at)icloud(dot)com>
To: pgsql-general(at)postgresql(dot)org
Subject: Dropping behavior for unique CONSTRAINTs
Date: 2023-03-02 20:30:41
Message-ID: 3d7d49f0-7eef-4d6d-8dc3-1993ba2fc2cb@me.com
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Hi folks,I'm curious if there are any docs supporting the functionality behind dropping unique constraints. For context, I am interested in enforcing uniqueness on a column. This table is heavily used, and I plan on dropping the constraint in the future. I wanted to avoid using a unique index since dropping them requires an exclusive lock and cannot be done concurrently. My thought was to then use a unique constraint, since I've read unofficial docs[0] that say these can be dropped safely with no lock.However, since a unique index would be the backing index to the unique constraint, I'm curious how this would work in practice (or if it even does!). Specifically if my theory of: "I can use a unique constraint to avoid obtaining an exclusive lock on my table" actually works.Thanks for any and all information, it's greatly appreciated, and apologies if I missed any existing documentation.Best, CSB0: https://leopard.in.ua/2016/09/20/safe-and-unsafe-operations-postgresql#.ZAEFpezMJLR 

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