Re: Can we get rid of repeated queries from pg_dump?

On Mon, Aug 30, 2021 at 10:11:22AM -0400, Tom Lane wrote:
> I don't suppose you could send me a schema-only dump of that
> database, off-list? I'm now quite curious.

Asked the owners for their permission.

> > The thing is - even though it was called 1804 times, dump contains data only
> > about 107 functions (pg_restore -l schema.dump | grep -c FUNCTION), so it kinda
> > seems that 94% of these calls is not needed.

> Hm. It's not doing that for *every* row in pg_proc, at least.
> I speculate that it is collecting and then not printing the info
> about functions that are in extensions --- can you check on
> how many there are of those?
> (Actually, if you've got a whole lot of objects inside extensions,
> maybe that explains the 5000 calls?)

Well, not sure if that's a lot, but:
there are 15 extensions, including plpgsql.

SELECT
count(*)
FROM
pg_catalog.pg_depend
WHERE
refclassid = 'pg_catalog.pg_extension'::pg_catalog.regclass
AND deptype = 'e';

return 2110 objects:

SELECT
classid::regclass,
count(*)
FROM
pg_catalog.pg_depend
WHERE
refclassid = 'pg_catalog.pg_extension'::pg_catalog.regclass
AND deptype = 'e'
GROUP BY
1
ORDER BY
1;

classid │ count
─────────────────────────┼───────
pg_type │ 31
pg_proc │ 1729
pg_class │ 61
pg_foreign_data_wrapper │ 1
pg_cast │ 30
pg_language │ 1
pg_opclass │ 73
pg_operator │ 111
pg_opfamily │ 73
(9 rows)

Best regards,

depesz