pgstac seems to require globally unique item IDs contrary to STAC spec about pgstac

[bitner]

This is correct, currently pgstac is set to that items have a globally unique id. The key word in the spec is should as opposed to must. There is some level of overhead in keeping multi-column primary keys rather than single column and the use case / catalog that PGStac was initially created for prioritized reducing that overhead.

[robintw]

Thanks - that makes perfect sense.

[duckontheweb]

currently pgstac is set to that items have a globally unique id.

Actually, I don't think this is true. The example above shows that there is a uniqueness constraint on the combination of datetime and id. If someone inserted another Item with the same id but a different datetime then it would not violate the uniqueness constraint. This issue appears to have been raised for PgSTAC < 0.5.0; for versions of PgSTAC >= 0.5.0 the same would apply to unique combinations of collection and id.

This does not change the original response to this post, but does have implications for stac-utils/stac-fastapi#381.