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Re: Primary keys and composite unique keys(basic question)

From:	Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>
To:	Merlin Moncure <mmoncure(at)gmail(dot)com>, Mohan Radhakrishnan <radhakrishnan(dot)mohan(at)gmail(dot)com>
Cc:	pgsql-general <pgsql-general(at)lists(dot)postgresql(dot)org>
Subject:	Re: Primary keys and composite unique keys(basic question)
Date:	2021-04-02 08:40:00
Message-ID:	69a5b7b83689ab456dd4b3cd7eb08e9573652039.camel@cybertec.at
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On Thu, 2021-04-01 at 21:28 -0500, Merlin Moncure wrote:
> I would never use UUIDS for keys though.

That makes me curious for your reasons.

I see the following disadvantages:

- A UUID requires twice as much storage space as a bigint.

- B-tree indexes are space optimized for inserting at the
rightmost leaf page, but UUIDs are random.

- UUIDs are more expensive to generate.

On the other hand, many processes trying to insert into
the same index page might lead to contention.

Is there anything I have missed?

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