Re: Horribly slow pg_upgrade performance with many Large Objects

Hannu Krosing <hannuk@google.com>

From: Hannu Krosing <hannuk@google.com>

To: Nathan Bossart <nathandbossart@gmail.com>

Cc: Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>

Date: 2025-04-08T19:41:06Z

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

On Tue, Apr 8, 2025 at 8:39 PM Nathan Bossart <nathandbossart@gmail.com> wrote:
>
...
>
> I've also verified that the dependency information is carried over in
> upgrades to later versions (AFAICT all the supported ones).

If I remember correctly the change to not copying
pg_largeobject_metadata data file but instead moving LOs as part of
schema was done in v12 when oid,, which had been a system column in
v11, became a user column, so upgrade to v11 is likely also missing
the dependencies