Date: Thu, 28 Mar 2019 12:39:18 -0300
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Simon Riggs <simon@2ndquadrant.com>
Cc: Pg Hackers <pgsql-hackers@lists.postgresql.org>,
	David Fetter <david@fetter.org>,
	Robert Haas <robertmhaas@gmail.com>,
	Rahila Syed <rahila.syed@2ndquadrant.com>,
	Pavan Deolasee <pavan.deolasee@gmail.com>,
	Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
Subject: Re: monitoring CREATE INDEX [CONCURRENTLY]
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On 2019-Mar-28, Simon Riggs wrote:

> On Thu, 28 Mar 2019 at 14:56, Alvaro Herrera <alvherre@2ndquadrant.com>
> wrote:
> 
> > I have not reinstated phase numbers; I have Rahila's positive vote for
> > them.  Do I hear any more votes on this issue?
> 
> If there is a specific technical issue, I'd like to understand that more.

There's no technical issue -- that's pretty straightforward.  Earlier
versions of the patch had them, and removing them only meant editing
strings in a couple of places.

> If it is just a usability preference, then I say we should have numbers.
> 
> Numbering is natural for people. If we say "It's currently doing phase
> XYZ", they will say "Is that the 3rd phase?", we'll say "No, actually the
> 5th", and then they will say "Why didn't you just number them?"

There are eight phases.  If you run normal CREATE INDEX (not concurrent)
then you get phases 1, then 3, done.  If you run CIC you get phases from
1 to 8.  Phase 3 "building index" has arbitrary subphases (they depend
on AM) in both cases.

I think the lack of phase numbering comes from the fact that the first
command we did (VACUUM) sometimes jumps backwards in phase numbers, so
it would be a bit absurd from users's POV.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services