Re: pg_upgrade failing for 200+ million Large Objects

On Sat, Mar 20, 2021 at 11:23:19AM -0400, Tom Lane wrote:
> I wonder if pg_dump could improve matters cheaply by aggregating the
> large objects by owner and ACL contents. That is, do
>
> select distinct lomowner, lomacl from pg_largeobject_metadata;
>
> and make just *one* BLOB TOC entry for each result. Then dump out
> all the matching blobs under that heading.
>
> A possible objection is that it'd reduce the ability to restore blobs
> selectively, so maybe we'd need to make it optional.
>
> Of course, that just reduces the memory consumption on the client
> side; it does nothing for the locks. Can we get away with releasing the
> lock immediately after doing an ALTER OWNER or GRANT/REVOKE on a blob?

Well, in pg_upgrade mode you can, since there are no other cluster
users, but you might be asking for general pg_dump usage.

--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EDB https://enterprisedb.com

If only the physical world exists, free will is an illusion.