Re: pgsql: Fix table rewrites that include a column without a default.

Hi,

On 2019-10-10 17:16:08 -0400, Tom Lane wrote:
> If you just want to verify that a rewrite happened or didn't happen,
> seems like you could check whether the table's relfilenode changed.
>
> regression=# select relfilenode as oldfilenode from pg_class where relname = 'rewrite_test'
> regression-# \gset
> regression=# select relfilenode != :oldfilenode as changed from pg_class where relname = 'rewrite_test';
> changed
> ---------
> f
> (1 row)
> regression=# alter table rewrite_test alter column notempty3_norewrite type bigint;
> ALTER TABLE
> regression=# select relfilenode != :oldfilenode as changed from pg_class where relname = 'rewrite_test';
> changed
> ---------
> t
> (1 row)

This felt verbose to me over a number of to-be-tested statements, so I
instead replaced it with a plpgsql function that EXECUTEs the DDL and
returns whether a rewrite happened. I'll assume/hope that that fixes the
occasional bf failures.

Greetings,

Andres Freund