Re: Horribly slow pg_upgrade performance with many Large Objects

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>

To: Hannu Krosing <hannuk@google.com>

Cc: Nathan Bossart <nathandbossart@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>

Date: 2025-04-08T16:37:43Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

pg_upgrade: Use COPY for large object metadata.
- 161a3e8b682e 19 (unreleased) landed
pg_dump: Fix object-type sort priority for large objects.
- fb6c860bbd1f 19 (unreleased) landed
- e43fae199e50 17.6 landed
- 36026b0fe3ab 18.0 landed
pg_upgrade: Mention that we preserve database OIDs in a comment.
- e2665efd0f4d 18.0 landed
pg_upgrade: Preserve database OIDs.
- aa01051418f1 15.0 cited
Fix pg_upgrade for oid removal.
- 12a53c732ced 12.0 cited

Hannu Krosing <hannuk@google.com> writes:
> I think we do preserve role oids

Oh ... I'd been looking for mentions of "role" in
pg_upgrade_support.c, but what I should have looked for was
"pg_authid".  So yeah, we do preserve role OIDs, and maybe that's
enough to make this workable, at least with source versions that
share the same rules for what goes into pg_largeobject_metadata and
pg_shdepend.  It's not something I'd risk back-patching though.

			regards, tom lane