Slow queries till Nextcloud 30.0.1

Steps to reproduce

1. migrate from 29.0.x to 30.0.1
2. display files page
3. show processes list in mariadb

Expected behaviour

No delay as previous version

Actual behaviour

The page is loading for a long time, nearly 20sec.
It seems to be caused by slow queries in mariadb (example below)

Server configuration

**Operating system: Ubuntu 22.04

**Web server: nginx

**Database: mariadb 10.6.18

**PHP version: 8.3

**Nextcloud version: 30.0.1

**Group folders version: 18.0.3

**Are you using external storage, if yes which one: no

**Are you using encryption: no

**Are you using an external user-backend, if yes which one: LDAP

Client configuration

**Browser: all (Chrome, firefox, safari...)

**Operating system: all (Mac, Windows, Linux)

Logs

example of slow query:
SELECT f.folder_id, f.mount_point, f.quota, f.acl, c.fileid, c.storage, c.path, c.name, c.mimetype, c.mimepart, c.size, c.mtime, c.storage_mtime, c.etag, c.encrypted, c.parent, a.permissions AS group_permissions, c.permissions AS permissions FROM oc_group_folders f INNER JOIN oc_group_folders_groups a ON f.folder_id = a.folder_id LEFT JOIN oc_filecache c ON (c.name = CONCAT(f.folder_id, '')) AND (c.parent = '12345') LEFT JOIN oc_circles_membership w_j ON (w_j.single_id = 'abcdefghijklmnopqrstuvwxyz12345') AND (w_j.circle_id = a.circle_id) LEFT JOIN oc_circles_circle w_j_k ON w_j.circle_id = w_j_k.unique_id WHERE w_j.level >= 1;

Start with the listed migration and files-page reproduction, then inspect the slow query in the MariaDB process list under the reported configuration. Compare behavior with Nextcloud 29.0.x and trace the group-folders query shown in the report. Done means the files page no longer incurs the reported nearly 20-second delay.