>Or, does the backend swallow the error, and return only the ReadyForQuery
(I hope not).
What is your backend version?
Here's a well-known case when the backend did swallow the error:
"Error on failed COMMIT"
https://www.postgresql.org/message-id/b9fb50dc-0f6e-15fb-6555-8ddb86f4aa71%40postgresfriends.org
I don't remember if the behavior has been fixed or not.
The expected behavior was "commit" returned "rollback" status without any
error.
Vladimir