Defaulting psql to ON_ERROR_ROLLBACK=interactive

All,

Ads and I were talking over breakfast about usability issues and he
mentioned transaction cancellation during interactive sessions as a serious
pain point.

I suggest we update the default of ON_ERROR_ROLLBACK to interactive for
10.0.

The last discussion I could find about this subject was in 2011 and while
there was concern about setting the default to "on" (as this would tamper
with the expected behaviour of scripts), I don't see any identification of
a problem that would be caused by setting it to "interactive" by default.

https://www.postgresql.org/message-id/CABwTF4V_J47GaryQcHD5Xe9gR57=shiYaKgRTjBCUsFQFvpByA@mail.gmail.com

It's quite clear to me that the current default behaviour costs the world
serious pain and heart-ache on a daily basis. I myself have made this
mistake in the middle of a long transaction (as my former colleague Will
describes in the previous thread) and I can only imagine others have as
well.

A few preemptive rejoinders to the obvious objections:

- We shouldn't optimize for people who make mistakes.

It may well be that you don't make mistakes, but I do, and I expect I am
hardly the less competent person using Postgres, so we should design our
system accordingly.

- Anyone who wants this can set it in their .psqlrc already.

Most people won't know about .psqlrc, and even fewer will set it. Worse, by
the time you realize you don't have it set, it will be too late to do
anything about.

If folks are comfortable with this change, I'll provide a patch for the
current commitfest.

--
Peter van Hardenberg
San Francisco, California
"Everything was beautiful, and nothing hurt."—Kurt Vonnegut