Where is the best place to generate a uuid for a base? In code or in sql query?

Question

PostgreSQL

Well, the whole question is in the title. You need to generate uuid for primary keys. It is better to generate in the code or in the request by the function.
In general, one gets the feeling that there is no difference, but still decided to clarify.

Answer 1

In code, because it's easier to unit test or bind entities

Answer 2

By and large, it doesn't matter.
But it strongly depends on how the UUID is generated on the client.
For example, when using rand based on time, I encountered a uniqueness problem when inserting records densely into the database (with a record density of more than 10K per sec, this error will manifest itself stably).

Answer 3

On the client. This is probably the main reason why to use uuid. You can generate it not centrally.