[Bug]: (Files) After uploading a file, the files list becomes empty

[lufer22]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

The files list becomes empty after uploading something to it.
I researched what was causing this and solved it by accessing the database and deleting some rows from the oc_filecache table.
When I ran the query DELETE FROM oc_filecache WHERE path LIKE '%preview%', the files appeared again, but sometimes I needed to run occ files:scan --all to completely solve the problem.

However, after some time, the list became empty again, probably due to a background job.

When I executed occ preview:repair, the problem reappeared.

Before uploading:

After uploading:

I managed to simulate the problem using the upload button, but it seems to occur when I run the files:scan or preview:repair commands.
I know it's confusing, but I don't know where to find the solution for this.

Steps to reproduce

1. Open the Files app.
2. Upload a file.
3. Observe that the files list becomes empty.

Expected behavior

Upload the files and see them listed normally.

Nextcloud Server version

30

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.3

Web server

Apache (supported)

Database engine version

MariaDB

Is this bug present after an update or on a fresh install?

Upgraded to a MAJOR version (ex. 28 to 29)

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

{
    "system": {
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "log_type": "file",
        "logfile": "\/var\/log\/groupware\/groupware_s4.log",
        "loglevel": 0,
        "logdateformat": "F d, Y H:i:s",
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "default_language": "pt",
        "default_locale": "pt_BR",
        "dbtype": "mysql",
        "overwrite.cli.url": "http:\/\/localhost",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "allow_local_remote_servers": true,
        "lost_password_link": "disabled",
        "simpleSignUpLink.shown": false,
        "updater.release.channel": "git",
        "upgrade.disable-web": true,
        "updatechecker": false,
        "has_internet_connection": false,
        "trashbin_retention_obligation": "auto,10",
        "knowledgebaseenabled": false,
        "profile.enabled": false,
        "allow_user_to_change_display_name": false,
        "auth.bruteforce.protection.enabled": false,
        "activity_expire_days": 30,
        "app.mail.verify-tls-peer": false,
        "auth.webauthn.enabled": false,
        "overwriteprotocol": "https",
        "appstoreenabled": false,
        "user_backends": [
            {
                "class": "\\OCA\\UserExternal\\IMAP",
                "arguments": [
                    "127.0.0.1",
                    143,
                    null,
                    null,
                    false,
                    false
                ]
            }
        ],
        "memcache.local": "\\OC\\Memcache\\APCu",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": "0",
            "password": "***REMOVED SENSITIVE VALUE***",
            "dbindex": 0,
            "timeout": 1.5,
            "read_timeout": 1.5
        },
        "memcached_server": [
            "localhost",
            "\/tmp\/memcached.sock"
        ],
        "theme": "",
        "trusted_domains": [
            "localhost",
            "devlucas.internetcontrolada.com"
        ],
        "mail_smtpmode": "smtp",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "587",
        "mail_smtpauth": true,
        "mail_smtpauthtype": "LOGIN",
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpstreamoptions": {
            "ssl": {
                "allow_self_signed": true,
                "verify_peer": false,
                "verify_peer_name": false
            }
        },
        "version": "30.0.4.1",
        "maintenance": false
    }
}

List of activated Apps

Enabled:
  - activity: 3.0.0
  - calendar: 5.0.6
  - calendar_resource_management: 0.8.0
  - cloud_federation_api: 1.13.0
  - comments: 1.20.1
  - contacts: 6.1.1
  - contactsinteraction: 1.11.0
  - dashboard: 7.10.0
  - dav: 1.31.1
  - deck: 1.14.2
  - federatedfilesharing: 1.20.0
  - files: 2.2.0
  - files_pdfviewer: 3.0.0
  - files_reminders: 1.3.0
  - files_sharing: 1.22.0
  - files_trashbin: 1.20.1
  - logreader: 3.0.0
  - lookup_server_connector: 1.18.0
  - notifications: 3.0.0
  - oauth2: 1.18.1
  - provisioning_api: 1.20.0
  - settings: 1.13.0
  - sharebymail: 1.20.0
  - snappymail: 2.38.2
  - spreed: 20.1.0
  - systemtags: 1.20.0
  - tasks: 0.16.1
  - theming: 2.5.0
  - theming_customcss: 1.17.0
  - twofactor_backupcodes: 1.19.0
  - updatenotification: 1.20.0
  - user_external: 3.4.0
  - user_status: 1.10.0
  - viewer: 3.0.0
  - weather_status: 1.10.0
  - webhook_listeners: 1.1.0-dev
  - workflowengine: 2.12.0
Disabled:
  - admin_audit: 1.20.0
  - encryption: 2.18.0
  - federation: 1.20.0 (installed 1.20.0)
  - files_external: 1.22.0
  - files_versions: 1.23.0 (installed 1.23.0)
  - notify_push: 0.7.0
  - profile: 1.0.0
  - testing: 1.20.0
  - twofactor_totp: 12.0.0-dev
  - user_ldap: 1.21.0
  - user_migration: 7.0.1

Nextcloud Signing status

Nextcloud Logs

Additional info

No response

[joshtrichards]

Anything notable about the filename?

What appears in your Nextcloud log?

Also, check your browser inspector Console and Network tab for possible clues.

[lufer22]

Hey!

Sorry for the delayed response.

Anything notable about the filename?
I tested files with '-' and '_' in their names.
This issue is a bit confusing because I simulated it with and without these characters, and it still occurred. Therefore, I don't believe the filename has any effect.

What appears in your Nextcloud log?
When I upload a file, I usually get this exception, but it doesn't happen every time:

However, this exception occurs more frequently:

Also, check your browser inspector Console and Network tab for possible clues.
I checked the browser Console and Network tabs, but no errors were found:

After uploading a file, the file list remains empty:

Hope it helps!

[edgarlemke]

Hi there.
For context I work in the same team as of @lufer22 .
After dwelling a long time on this bug, it seems to be a database-related thing. I've even opened an issue on MariaDB bug tracking. So not sure it's a Nextcloud bug.

To fix it, we've done the following:

diff --git a/lib/private/Files/Cache/CacheQueryBuilder.php b/lib/private/Files/Cache/CacheQueryBuilder.php
index 76eb2bfa5ca..00035b67494 100644
--- a/lib/private/Files/Cache/CacheQueryBuilder.php
+++ b/lib/private/Files/Cache/CacheQueryBuilder.php
@@ -94,7 +94,9 @@ class CacheQueryBuilder extends ExtendedQueryBuilder {
                        $alias = '';
                }
 
-               $this->andWhere($this->expr()->eq("{$alias}parent", $this->createNamedParameter($parent, IQueryBuilder::PARAM_INT)));
+               $this->createNamedParameter($parent, IQueryBuilder::PARAM_INT);
+               $eq = "CAST({$alias}parent AS SIGNED) = :dcValue1";
+               $this->andWhere($eq);
 
                return $this;
        }

It's hackish but it seems to work. Any suggestions would be appreciated.

However I find it very smelly that the parent column in the filecache table can receive -1 as a value. Is there a reason for using a negative value for signaling a missing parent? Why not just NULL? Assuming -2, -3... are not expected values, it also has the disadvantage of wasting half the space of the 64 bit representation space of the BIGINT. Even if it's probably not going to be used anyway, it kinda obscures the intention.

[joshtrichards]

Good catch, but according to your MariaDB bug report you're using MariaDB 11.1.2 which is not supported by MariaDB at this point (and Nextcloud Server never supported it).

11.1.2

This is short-term only release. And outdated even within the 11.1.x series, since the last bug fix release was 11.1.6.

We only support the usage of long-term MariaDB database versions with Nextcloud Server.

For what it's worth, the query as-is works for me in my test environments (in supported and up-to-date MariaDB versions).

So it does appear to have been a MariaDB bug, but also one that is (a) since fixed; (b) possibly avoidable by sticking with supported long-term releases. ;-)

Refs:

• https://docs.nextcloud.com/server/stable/admin_manual/installation/system_requirements.html#server
• https://mariadb.com/kb/en/mariadb-server-release-dates/
• https://mariadb.com/kb/en/release-notes-mariadb-11-1-series/

[nextcloud-command]

This issue has been automatically marked as stale because it has not had recent activity and seems to be missing some essential information. It will be closed if no further activity occurs. Thank you for your contributions.