Horton

Re: Schema variables - new implementation for Postgres 15

Alvaro Herrera <alvherre@alvh.no-ip.org>

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Dmitry Dolgov <9erthalion6@gmail.com>
Cc: Pavel Stehule <pavel.stehule@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, Sergey Shinderuk <s.shinderuk@postgrespro.ru>, Tomas Vondra <tomas.vondra@enterprisedb.com>, Julien Rouhaud <rjuju123@gmail.com>, dean.a.rasheed@gmail.com, er@xs4all.nl, joel@compiler.org, pgsql-hackers@lists.postgresql.org
Date: 2024-05-18T11:29:09Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Allow underscores in integer and numeric constants.

  2. Remove special outfuncs/readfuncs handling of RangeVar.catalogname.

  3. Remove extra space from dumped ALTER DEFAULT PRIVILEGES.

  4. Create FKs properly when attaching table as partition

  5. psql: improve tab-complete's handling of variant SQL names.

On 2024-Jan-30, Dmitry Dolgov wrote:

> Yep, in this constellation the implementation holds much better (in
> terms of memory) in my create/let/drop testing.
> 
> I've marked the CF item as ready for committer, but a note for anyone
> who would like to pick up it from here -- we're talking about first 5
> patches here, up to the memory cleaning after DROP VARIABLE. It doesn't
> mean the rest is somehow not worth it, but I believe it's a good first
> step.

Hmm, I think patch 16 is essential, because the point of variable shadowing
is a critical aspect of how the whole thing works.  So I would say that
a first step would be those first five patches plus 16.

I want to note that when we discussed this patch series at the dev
meeting in FOSDEM, a sort-of conclusion was reached that we didn't want
schema variables at all because of the fact that creating a variable
would potentially change the meaning of queries by shadowing table
columns.  But this turns out to be incorrect: it's _variables_ that are
shadowed by table columns, not the other way around.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"No hay ausente sin culpa ni presente sin disculpa" (Prov. francés)