Re: pg_rewind and log messages

Heikki Linnakangas wrote:
> On 04/07/2015 05:59 AM, Michael Paquier wrote:

> >Fix inconsistent handling of logs in pg_rewind
> >
> >pg_rewind was handling a couple of things differently compared to the
> >other src/bin utilities:
> >- Logging output needs to be flushed on stderr, not stdout
>
> Agreed in general. But there's also precedent in printing some stuff to
> stdout: pg_ctl does that for the status message, like "server starting". As
> does initdb.
>
> I'm pretty unclear on what the rule here is.

One principle that sometimes helps is to consider what happens if you
use the command as part of a larger pipeline; progress messages can be
read by some other command further down (and perhaps report them in a
dialog box, if you embed the program in a GUI, say), but error messages
should probably be processed differently; normally the pipeline would be
aborted as a whole.

--
Álvaro Herrera http://www.2ndQuadrant.com/
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