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>, pgsql-hackers@lists.postgresql.org
Date: 2019-12-04T20:17:21Z
Lists: pgsql-hackers

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On 2019-12-04 15:14, Tom Lane wrote:
> Run the regression tests with "make installcheck", then:
> 
> $ pg_dump -Fc regression >r.dump
> $ createdb r2
> $ pg_restore -d r2 r.dump
> pg_restore: while PROCESSING TOC:
> pg_restore: from TOC entry 6005; 2604 24821 DEFAULT gtest1_1 b postgres
> pg_restore: error: could not execute query: ERROR:  column "b" of relation "gtest1_1" is a generated column
> Command was: ALTER TABLE ONLY public.gtest1_1 ALTER COLUMN b SET DEFAULT (a * 2);
> 
> 
> pg_restore: warning: errors ignored on restore: 1
> $
> 
> It looks like gtest1_1 inherits column "b" from gtest1, so possibly
> pg_dump is just confused about the combination of inheritance and
> generated columns.

Yeah, there was some stuff about the "separate" dumping of defaults that 
I apparently forgot to address.  The attached patch fixes it.  I'll see 
about adding a test case for it, too.

> I see this in v12 as well as HEAD.  One interesting question is how come
> the pg_upgrade test isn't failing --- maybe binary-upgrade mode handles
> this case differently?

Binary upgrade dumps out even inherited columns, so it won't run into 
the "separate" case that's the issue here.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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