That is true. Mandating UTC is not the only way to eliminate ambiguity. Apologies for appearing to suggest that this is case.
Fair point.
The domain approach is what has been implemented and has been running in production for some time without a problem (that we know of).
The cost of this appears to be quite trivial in Postgres - there are 2 lines of DDL in the OP that describe the implementation and it seems to work.
The reason why I started this thread is because somebody on a JDBC related list told me that I was crazy for trying to do this and that I had most likely misunderstood how Postgres works. So respecting their opinion, I decided to ask the Postgres experts.
It is heartening to hear Tom say that the idea is not completely insane, but questions the business value of mandating UTC, given there are other ways to ensure timezone explicitness across the app(s) and the database.
I’m also somewhat wiser about Postgres works now as well.
The bit I’m ignorant of is that the domain approach appears to work with the timestampz wire representation. Apps seem to bind using the platform timestampz representation and the server barfs if the app forgets to enforce UTC.
