RE: pg_upgrade and logical replication

Dear Justin,

Thanks for replying!

> What optimizations?  I can't see them, and since the patch is described
> as rearranging test cases (and therefore already difficult to read), I
> guess they should be a separate patch, or the optimizations described.

The basic idea was to reduce number of CREATE/DROP statement,
but it was changed for now - publications and subscriptions were created and
dropped per testcases.

E.g., In case of successful upgrade, below steps were done:

1. create two publications
2. create a subscription with failover = true
3. avoid further initial sync by setting max_logical_replication_workers = 0
4. create another subscription
5. confirm statuses of tables are either of 'i' or 'r'
6. run pg_upgrade
7. confirm table statuses are preserved
8. confirm replication origins are preserved.

New patch is available in [1].

[1]:
https://www.postgresql.org/message-id/TYCPR01MB12077B16EEDA360BA645B96F8F54C2%40TYCPR01MB12077.jpnprd01.prod.outlook.com

Best Regards,
Hayato Kuroda
FUJITSU LIMITED
https://www.fujitsu.com/