Horton

Re: Dumping/restoring fails on inherited generated column

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Cc: Masahiko Sawada <masahiko.sawada@2ndquadrant.com>, Daniel Gustafsson <daniel@yesql.se>, andrewbille@gmail.com, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2020-09-29T16:46:46Z
Lists: pgsql-hackers 
I wrote:
> The situation is different for GENERATED columns, since we disallow
> a child having a different GENERATED property than the parent.

BTW, that alleged prohibition is pretty damn leaky:

d3=# create table pp1 (a int, b int GENERATED ALWAYS AS (a * 2) STORED);
CREATE TABLE
d3=# create table cc1 (a int, b int GENERATED ALWAYS AS (a * 3) STORED);
CREATE TABLE
d3=# alter table cc1 inherit pp1;
ALTER TABLE

Maybe the *real* fix here is to give up on this idea that they
can't be different?

			regards, tom lane

Commits

  1. Fix ALTER TABLE / INHERIT with generated columns

  2. pg_dump: Fix dumping of inherited generated columns

  3. Disallow ALTER TABLE ONLY / DROP EXPRESSION

  4. Fix several DDL issues of generated columns versus inheritance