I think my oc_filecache is corrupted.
I started out with a migration from owncloud 9 to nextcloud 13. That went more or less ok. with some errors.
Just now - two weeks later - I found that my desktop client isn’t syncing anymore and I have trouble with Umlaute (ÄÜÖ).
In the web gui shows two folder “Pr?sentationen” and “Präsentationen”. “Pr?sentationen” doesn’t exist on the file system. The desktop client reports that the folder is deleted on the server. (The folder doesn’t existon the client as well. Because of the “?” in the name.
occ file:scan --all doesn’t solve the problem.
Checking the logs I found
Doctrine\DBAL\Exception\DriverException: An exception occurred while executing ' SELECT
fileid,
storage,
path,
parent,
name,
mimetype,
storage_mtime,
mimepart,
size,
mtime,
encrypted,
etag,
permissions,
checksumFROM
oc_filecacheWHERE
storage= ? AND
name COLLATE utf8mb4_general_ci LIKE ?' with params [1, "Oberjoch 2016.d1523202197\/\/Oberjoch 2016-2-_...gro\u00df wie die Berge..._.png.v%"]: SQLSTATE[42000]: Syntax error or access violation: 1253 COLLATION 'utf8mb4_general_ci' is not valid for CHARACTER SET 'utf8'
So I though converting the database to utf8mb4_general_ci would solve the problem. (occ db:convert-mysql-charset)
But that gives the following error message.
Doctrine\DBAL\Exception\DriverException: An exception occurred while executing 'ALTER TABLE
oc_filecache CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_bin;': SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 1000 bytes
When I truncate oc_filecache the folder “Pr?sentationen” is gone in the web gui. But also all my shared links.
Any idea how to fix that problem?