Re: Renaming of pg_xlog and pg_clog

Andres Freund <andres@anarazel.de>

From: Andres Freund <andres@anarazel.de>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Magnus Hagander <magnus@hagander.net>, Michael Paquier <michael.paquier@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2016-08-26T21:20:15Z
Lists: pgsql-hackers
On 2016-08-26 17:11:00 -0400, Peter Eisentraut wrote:
> On 8/26/16 12:28 PM, Tom Lane wrote:
> > Also, I'd just as soon not move/rename things
> > that don't really need it.
>
> I'm just as happy with not changing anything.  But if we're going to
> rename stuff, let's at least think about something slightly more
> comprehensive.  Any rename is going to break a bunch of stuff.  But if
> we break it in a way that reduces the need for future discussion or
> changes, it would at least be a small win in the long run.

I do think there's an order of magnitude between the impact between
moving some and moving everything. And that's going to impact
cost/benefit calculations.

Moving e.g. all ephemeral files into a (possibly configurable) directory
is going to hardly impact anyone.  Renaming pg_logical into something
different (FWIW, it was originally named differently...) will hopefully
impact nobody, excepting some out of date file exclusion lists possibly.

But moving config files, and even pg_xlog (which we document to be
symlinkable somewhere else) imo is different.

The other thing is that the likelihood of getting anywhere by doing
radical one-off redesigns is approximately 0.


Commits

  1. Rename "pg_clog" directory to "pg_xact".

  2. Improve error reporting in pg_upgrade's file copying/linking/rewriting.