The "-d, --dbname=DBNAME" option is mentioned in --help output, but pg_isready ignores nonexistent databases.
Is this an application bug, a minor doc bug or am I missing something?
It’s documented in the Notes section.
That seems odd. Why mention an option in --help if the option isn't needed?
Because it exists - and I figure most people should use it to not put spurious errors into the logs.
The person on the client side isn't thinking about what's going in the PG server's logs.
This is something that should be fixed. Very low priority, after the data corruption and feature bugs, and useful new features added, but either return an error code if the client user doesn't have access to that database, or remove the option.
It reports whether the cluster is ready, not any specific database or for any specific user. It works just fine for its intent. Sure, it could be modified to also do something different. But you haven't explained why that would be a worthwhile use of effort. All I'm seeing it admittedly a slightly non-intuitative specification that does require reading and some degree of caring on the part of the user. And probably some recognition that it works this way because the backend protocol doesn't allow for those values to be made optional and so the current implementation is a bit of a hack to get around that fact.
"Option exists, is mentioned in --help, but doesn't do anything" is a (very low priority) bug. That's plain and simple.
You'd say the same thing about a non-Postgresql program that you use, but you resist it in the system you're invested in.
