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

Andres Freund <andres(at)anarazel(dot)de> writes:
> Fix table rewrites that include a column without a default.

This patch added use of an event trigger in alter_table.sql.
As we have learned the hard way, it's not acceptable to create event
triggers in test scripts that run in parallel with anything else,
because they will intermittently screw up DDL happening in the
parallel scripts. As seen just now on clam:

https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=clam&dt=2019-10-10%2020%3A16%3A19

diff -U3 /home/pgbfarm/buildroot/HEAD/pgsql.build/src/test/regress/expected/plpgsql.out /home/pgbfarm/buildroot/HEAD/pgsql.build/src/test/regress/results/plpgsql.out
--- /home/pgbfarm/buildroot/HEAD/pgsql.build/src/test/regress/expected/plpgsql.out 2019-05-09 09:00:10.653795677 +0100
+++ /home/pgbfarm/buildroot/HEAD/pgsql.build/src/test/regress/results/plpgsql.out 2019-10-10 21:21:46.406007734 +0100
@@ -5419,6 +5419,7 @@
-- now change 'name' to an integer to see what happens...
ALTER TABLE alter_table_under_transition_tables
ALTER COLUMN name TYPE int USING name::integer;
+WARNING: rewriting table alter_table_under_transition_tables
UPDATE alter_table_under_transition_tables
SET name = (name::text || name::text)::integer;
WARNING: old table = 1=11,2=22,3=33, new table = 1=1111,2=2222,3=3333

Do you *really* need an event trigger to test this?

regards, tom lane