Re: Duplicate history file?

On Fri, Jun 11, 2021 at 03:32:28PM +0900, Kyotaro Horiguchi wrote:
> At Fri, 11 Jun 2021 10:48:32 +0800, Julien Rouhaud <rjuju123@gmail.com> wrote in
>> "far from perfect" is a strong understatement for "appears to work but will
>> randomly and silently breaks everything without a simple way to detect it".

Yeah.  Users like unplugging their hosts, because that's *fast* and
easy to do.

> I think it's overstating. It sounds like a story of a mission critical
> world.  How perfect archive_command should be depends on the
> requirements of every system.  Simple cp is actually sufficient in
> certain log? range of usages, maybe.
>
>> We should document a minimum workable setup, but cp isn't an example of that,
>> and I don't think that there will be a simple example unless we provide a
>> dedicated utility.
>
> I think cp can be an example as far as we explain the limitations. (On
> the other hand "test !-f" cannot since it actually prevents server
> from working correctly.)

Disagreed.  I think that we should not try to change this area until
we can document a reliable solution, and a simple "cp" is not that.
Hmm.  A simple command that could be used as reference is for example
"dd" that flushes the file by itself, or we could just revisit the
discussions about having a pg_copy command, or we could document a
small utility in perl that does the job.
--
Michael