Horton

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: pgsql-hackers@lists.postgresql.org
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Date: 2019-12-04T14:14:07Z
Lists: pgsql-hackers 
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.

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?

			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