Re: pg_upgrade and logical replication

On Tue, Jan 02, 2024 at 03:58:25PM +0530, Amit Kapila wrote:
> Pushed.

pg_upgrade/t/004_subscription.pl says

|my $mode = $ENV{PG_TEST_PG_UPGRADE_MODE} || '--copy';

..but I think maybe it should not.

When you try to use --link, it fails:
https://cirrus-ci.com/task/4669494061170688

|Adding ".old" suffix to old global/pg_control ok
|
|If you want to start the old cluster, you will need to remove
|the ".old" suffix from /tmp/cirrus-ci-build/build/testrun/pg_upgrade/004_subscription/data/t_004_subscription_old_sub_data/pgdata/global/pg_control.old.
|Because "link" mode was used, the old cluster cannot be safely
|started once the new cluster has been started.
|...
|
|postgres: could not find the database system
|Expected to find it in the directory "/tmp/cirrus-ci-build/build/testrun/pg_upgrade/004_subscription/data/t_004_subscription_old_sub_data/pgdata",
|but could not open file "/tmp/cirrus-ci-build/build/testrun/pg_upgrade/004_subscription/data/t_004_subscription_old_sub_data/pgdata/global/pg_control": No such file or directory
|# No postmaster PID for node "old_sub"
|[19:36:01.396](0.250s) Bail out! pg_ctl start failed

You could rename pg_control.old to avoid that immediate error, but that doesn't
address the essential issue that "the old cluster cannot be safely started once
the new cluster has been started."

--
Justin