Thread: Query to identify all collations in the current database that need to be refreshed

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/17/sql-altercollation.html
Description:

On the alter collation docs [1], it says "The following query can be used to
identify all collations in the current database that need to be refreshed
and the objects that depend on them"
```
SELECT pg_describe_object(refclassid, refobjid, refobjsubid) AS "Collation",
       pg_describe_object(classid, objid, objsubid) AS "Object"
  FROM pg_depend d JOIN pg_collation c
       ON refclassid = 'pg_collation'::regclass AND refobjid = c.oid
  WHERE c.collversion <> pg_collation_actual_version(c.oid)
  ORDER BY 1, 2;
```
This seems to be a bit optimistic, since in my postgres instance, the
`default` collation has `collversion` set to `NULL` which would not pass the
comparison. In addition, dependencies to `default` do not seem to be
encoded, as
```
SELECT pg_describe_object(refclassid, refobjid, refobjsubid) AS "Collation",
       pg_describe_object(classid, objid, objsubid) AS "Object"
  FROM pg_depend d JOIN pg_collation c
       ON refclassid = 'pg_collation'::regclass AND refobjid = c.oid
```
returns an empty row set. It seems like the description of the query is
inaccurate.
[1]
https://www.postgresql.org/docs/current/sql-altercollation.html#SQL-ALTERCOLLATION-NOTES