Horton

Re: Dumping/restoring fails on inherited generated column

Peter Eisentraut <peter.eisentraut@2ndquadrant.com>

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From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, Masahiko Sawada <masahiko.sawada@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-02-03T19:18:33Z
Lists: pgsql-hackers

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On 2021-01-29 17:41, Tom Lane wrote:
> Also, in the example from [2],
> 
> 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
> 
> pg_dump now omits to dump cc1's generation expression, which seems
> strictly worse than before.  Admittedly, the backend likely ought to
> be rejecting this scenario, but it doesn't do so today.
> 
> [2]https://www.postgresql.org/message-id/661371.1601398006%40sss.pgh.pa.us

Here is a WIP patch to address this.  Probably needs another look for 
column number mapping and all the usual stuff, but the basic idea should 
be okay.

-- 
Peter Eisentraut
2ndQuadrant, an EDB company
https://www.2ndquadrant.com/

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