Horton

Re: Improvements in psql hooks for variables

Daniel Verite <daniel@manitou-mail.org>

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From: "Daniel Verite" <daniel@manitou-mail.org>
To: "Tom Lane" <tgl@sss.pgh.pa.us>
Cc: "Ashutosh Sharma" <ashu.coek88@gmail.com>,"Rahila Syed" <rahilasyed90@gmail.com>,"Stephen Frost" <sfrost@snowman.net>,"Ashutosh Bapat" <ashutosh.bapat@enterprisedb.com>,"pgsql-hackers" <pgsql-hackers@postgresql.org>
Date: 2017-01-24T16:54:09Z
Lists: pgsql-hackers 
	Tom Lane wrote:

> However, it only really works if psql never overwrites the values
> after startup, whereas I believe all of these are overwritten by
> a \c command.

Yes, there are reset to reflect the properties of the new connection.

> So maybe it's more user-friendly to make these variables fully
> reserved, even at the risk of breaking existing scripts.  But
> I don't think it's exactly an open-and-shut question.

You mean if we make that fail:	\set ENCODING UTF8
it's going to make that fail too:
  SELECT something AS "ENCODING"[,...]	\gset
and I agree it's not obvious that this trade-off has to be
made. Personally I'm fine with the status quo and will
not add that hook into the patch unless pressed to.

Best regards,
-- 
Daniel Vérité
PostgreSQL-powered mailer: http://www.manitou-mail.org
Twitter: @DanielVerite

Commits

  1. Clean up psql's behavior for a few more control variables.

  2. Make psql's \set display variables in alphabetical order.

  3. Improve psql's behavior for \set and \unset of its control variables.

  4. Make psql reject attempts to set special variables to invalid values.