Re: Duplicate history file?

At Fri, 11 Jun 2021 10:48:32 +0800, Julien Rouhaud <rjuju123@gmail.com> wrote in 
> On Fri, Jun 11, 2021 at 11:25:51AM +0900, Kyotaro Horiguchi wrote:
> > 
> > Nevertheless I agree to it, still don't we need a minimum workable
> > setup as the first step? Something like below.
> > 
> > ===
> > The following is an example of the minimal archive_command.
> > 
> > Example: cp %p /blah/%f
> > 
> > However, it is far from perfect. The following is the discussion about
> > what is needed for archive_command to be more reliable.
> > 
> > <the long list of the requirements>
> > ====
> 
> "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".

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 actualy 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.

It looks somewhat strange like "Well, you need a special track to
drive your car, however, we don't have one. It's your responsibility
to construct a track that protects it from accidents perfectly.".

"Yeah, I'm not going to push it so hard and don't care it gets some
small scratches, couldn't I drive it on a public road?"

(Sorry for the bad analogy).

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.)

> It could however be something along those lines:
> 
> Example: archive_program %p /path/to/%d
> 
> archive_program being a script ensuring that all those requirements are met:
> <the long list of the requirements>

Isn't it almost saying that anything less than pgBackRest isn't
qualified as archive_program?


regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center