Horton

Re: Renaming of pg_xlog and pg_clog

Stephen Frost <sfrost@snowman.net>

View thread View on postgr.es
From: Stephen Frost <sfrost@snowman.net>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Michael Paquier <michael.paquier@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Thomas Munro <thomas.munro@enterprisedb.com>, Craig Ringer <craig.ringer@2ndquadrant.com>, Jim Nasby <Jim.Nasby@bluetreble.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Andres Freund <andres@anarazel.de>
Date: 2016-10-14T11:35:23Z
Lists: pgsql-hackers 
* Peter Eisentraut (peter.eisentraut@2ndquadrant.com) wrote:
> On 10/12/16 11:22 AM, Tom Lane wrote:
> > The main problem we're trying to fix here is people thinking that
> > something with "log" in the name contains discardable data.  Just
> > relocating the directory without renaming it won't improve that.
> 
> I think it would help if we moved it to something like
> "internal/pg_xlog" and "internal/pg_clog".  Keep the name but move it
> out of sight.

I disagree that this will materially help with the issue.

> We have a tool called pg_xlogdump in the standard installation.  initdb
> has an option --xlogdir, pg_basebackup has --xlog and others.  Renaming
> the xlog directory would make this all a bit confusing, unless we're
> prepared to rename the programs and options as well.

pg_xlogdump is not a user-facing tool, frankly, so I don't believe we
should be terribly concerned about either leaving it named as-is or
renaming it.  I agree that we should consider adding alternative names
to the options for initdb and pg_basebackup.

Thanks!

Stephen

Commits

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

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