Dear Hou,
Thanks for posting the patch! I want to open a question to gather opinions from others.
> > It was primarily for upgrade purposes only. So, as we can't see a good reason to
> > go via pg_dump let's do it in upgrade unless someone thinks otherwise.
>
> Removed the new option in pg_dump and modified the pg_upgrade
> directly use the slot info to restore the slot in new cluster.
In this version, creations of logical slots are serialized, whereas old ones were
parallelised per db. Do you it should be parallelized again? I have tested locally
and felt harmless. Also, this approch allows to log the executed SQLs.
Best Regards,
Hayato Kuroda
FUJITSU LIMITED