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

On Wed, Mar 31, 2021 at 3:36 AM Mohan Radhakrishnan
<radhakrishnan(dot)mohan(at)gmail(dot)com> wrote:
>
> Hello,
> We have UUIDs in our tables which are primary keys. But in some cases
> we also identify a composite unique key apart from the primary key.
>
> My assumption is that there should be a unique key index created by us using the composite key. And when we fetch using this composite key instead of the primary key we have a performance boost due to the index.
>
> Is this right ? Are there more details I should read to understand this better ? Please point. If I should use the query planner to look at the statistics I will.

This is one of the great debates in computer science and it is not
settled. There are various tradeoffs around using a composite key
derived from the data (aka natural key) vs generated identifiers. It's
a complex topic with many facets: performance, organization,
validation, and correctness are all relevant considerations. I would
never use UUIDS for keys though.

merlin