Default date style to "dmy" (or something less ambiguous)

[allenap]

The default "mdy" (month, day, year) configuration is appropriate for the US, but that's about it. It's confusing for everyone else. It would be nice to find a default that is not ambiguous/confusing for everyone. Failing that, "dmy" might be a more appropriate default than "mdy". This may equally be a non-issue if clients like psql do something locale-specific already.

[allenap]

There is a "ymd" option – see the docs – which might be the least ambiguous of all except that the year is only two digits 🤦

At this point I'm pretty sure it's better to avoid anything that must be disambiguated with the DateStyle setting. There are ways of inputting dates that are unambiguous which folks should absolutely use, and thus avoid DateStyle-related shenanigans – see those docs – and the principle of least surprise suggests sticking with the default date style of "mdy" otherwise, despite being perhaps the least suitable choice for most people.

Display of dates is unaffected: that's governed by the first part of the DateStyle setting, and that defaults to ISO, which is thankfully well recognised and I assume unambiguous in any region.

I'm going to leave this issue open for a bit in case I think of something new, or someone else comments, but it's likely that this is going to get closed without any change being made. Perhaps it's useful to put this in the documentation though.