[Bug]: Generating previews: General error: 1205 Lock wait timeout exceeded

[thomasmerz]

⚠️ 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

I did this:

# occ preview:generate-all -p "/thomas/files/Photos"

And I got that:

2026-03-11T11:52:31+00:00 Scanning folder /thomas/files/Photos
2026-03-11T11:52:31+00:00 Scanning folder /thomas/files/Photos/.stfolder
2026-03-11T11:52:31+00:00 Scanning folder /thomas/files/Photos/.stversions
2026-03-11T11:52:31+00:00 Scanning folder /thomas/files/Photos/Benutzerkonten
2026-03-11T11:59:29+00:00
2026-03-11T11:59:29+00:00 In DbalException.php line 56:
2026-03-11T11:59:29+00:00
2026-03-11T11:59:29+00:00   An exception occurred while executing a query: SQLSTATE[HY000]: General error: 1205 Lock wait timeout exceeded; try restarting transaction
2026-03-11T11:59:29+00:00
2026-03-11T11:59:29+00:00
2026-03-11T11:59:29+00:00 In ExceptionConverter.php line 44:
2026-03-11T11:59:29+00:00
2026-03-11T11:59:29+00:00   An exception occurred while executing a query: SQLSTATE[HY000]: General error: 1205 Lock wait timeout exceeded; try restarting transaction
2026-03-11T11:59:29+00:00
2026-03-11T11:59:29+00:00
2026-03-11T11:59:29+00:00 In Exception.php line 24:
2026-03-11T11:59:29+00:00
2026-03-11T11:59:29+00:00   SQLSTATE[HY000]: General error: 1205 Lock wait timeout exceeded; try restarting transaction
2026-03-11T11:59:29+00:00
2026-03-11T11:59:29+00:00
2026-03-11T11:59:29+00:00 In Statement.php line 130:
2026-03-11T11:59:29+00:00
2026-03-11T11:59:29+00:00   SQLSTATE[HY000]: General error: 1205 Lock wait timeout exceeded; try restarting transaction
2026-03-11T11:59:29+00:00
2026-03-11T11:59:29+00:00
2026-03-11T11:59:29+00:00 preview:generate-all [-p|--path [PATH]] [-w|--workers [WORKERS]] [--] [<user_id>...]
2026-03-11T11:59:29+00:00

Before this I cleaned up previews:

# occ preview:cleanup -vv

Preview folder deleted
Preview folder recreated
Previews removed

Steps to reproduce

occ preview:generate-all -p … does reproduce this.

Expected behavior

When generating previews it should not get a General error: 1205 Lock wait timeout exceeded.

Nextcloud Server version

33

Operating system

Other

PHP engine version

PHP 8.4

Web server

Nginx

Database engine version

MariaDB

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

Upgraded to a MAJOR version (ex. 31 to 32)

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

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

Configuration report

{
    "system": {
        "memcache.local": "\\OC\\Memcache\\APCu",
        "apps_paths": [
            {
                "path": "\/var\/www\/html\/apps",
                "url": "\/apps",
                "writable": false
            },
            {
                "path": "\/var\/www\/html\/custom_apps",
                "url": "\/custom_apps",
                "writable": true
            }
        ],
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": 6379
        },
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "my.domain.com",
            "myother.domain2.de"
        ],
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "forwarded_for_headers": [
            "HTTP_X_FORWARDED",
            "HTTP_FORWARDED_FOR"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "33.0.0.16",
        "overwrite.cli.url": "https:\/\/my.domain.com",
        "overwriteprotocol": "https",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "3306",
        "dbtableprefix": "",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "updater.release.channel": "stable",
        "mail_smtpmode": "smtp",
        "mail_smtpsecure": "ssl",
        "mail_sendmailmode": "smtp",
        "mail_smtpauth": 1,
        "mail_smtpauthtype": "LOGIN",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "465",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "twofactor_enforced": "false",
        "twofactor_enforced_groups": [],
        "twofactor_enforced_excluded_groups": [],
        "maintenance": false,
        "loglevel": 2,
        "app_install_overwrite": [
            "quota_warning",
            "occweb",
            "memories",
            "maps"
        ],
        "theme": "",
        "default_phone_region": "GER",
        "trashbin_retention_obligation": "auto,31",
        "maintenance_window_start": 1,
        "memories.exiftool": "\/var\/www\/html\/custom_apps\/memories\/bin-ext\/exiftool-amd64-musl",
        "memories.vod.path": "\/var\/www\/html\/custom_apps\/memories\/bin-ext\/go-vod-amd64",
        "enabledPreviewProviders": [
            "OC\\Preview\\Image"
        ],
        "preview_max_x": 2048,
        "preview_max_y": 2048,
        "memories.index.path.blacklist": ".hetzner|.pixx|\\\/Music|\\\/My .*|\\\/Videos",
        "memories.db.triggers.fcu": true
    }
}

List of activated Apps

Enabled:
  - activity: 6.0.0-dev.0
  - admin_audit: 1.23.0
  - app_api: 33.0.0
  - bruteforcesettings: 6.0.0-dev.0
  - calendar: 6.2.1
  - circles: 33.0.0
  - cloud_federation_api: 1.17.0
  - contacts: 8.4.0
  - dav: 1.36.0
  - event_update_notification: 2.8.0
  - federatedfilesharing: 1.23.0
  - files: 2.5.0
  - files_downloadlimit: 5.1.0-dev.0
  - files_external: 1.25.1
  - files_reminders: 1.6.0
  - files_sharing: 1.25.2
  - files_trashbin: 1.23.0
  - firstrunwizard: 6.0.0-dev.0
  - forms: 5.2.5
  - logreader: 6.0.0
  - lookup_server_connector: 1.21.0
  - memories: 7.8.2
  - nextcloud_announcements: 5.0.0
  - notifications: 6.0.0
  - notify_push: 1.3.0
  - oauth2: 1.21.0
  - occweb: 0.2.3
  - password_policy: 5.0.0-dev.0
  - previewgenerator: 5.13.0
  - privacy: 5.0.0-dev.0
  - profile: 1.2.0
  - provisioning_api: 1.23.0
  - quota_warning: 1.23.0
  - related_resources: 4.0.0-dev.0
  - serverinfo: 5.0.0-dev.0
  - settings: 1.16.0
  - sharebymail: 1.23.0
  - spreed: 23.0.1
  - survey_client: 5.0.0-dev.0
  - theming: 2.8.0
  - twofactor_backupcodes: 1.22.0
  - twofactor_totp: 15.0.0-dev.0
  - updatenotification: 1.23.0
  - viewer: 6.0.0-dev.0
  - webhook_listeners: 1.5.0
  - workflowengine: 2.15.0
Disabled:
  - comments: 1.23.0 (installed 1.5.0)
  - contactsinteraction: 1.14.1 (installed 1.1.0)
  - dashboard: 7.13.0 (installed 6.0.0)
  - encryption: 2.21.0
  - federation: 1.23.0 (installed 1.5.0)
  - files_pdfviewer: 6.0.0-dev.0 (installed 4.0.0)
  - files_retention: 4.0.0 (installed 4.0.0)
  - files_versions: 1.26.0 (installed 1.17.0)
  - maps: 1.6.0 (installed 1.6.0)
  - photos: 6.0.0-dev.0 (installed 5.0.0-dev.1)
  - recognize: 11.0.1 (installed 11.0.1)
  - recommendations: 6.0.0-dev.0 (installed 0.8.0)
  - support: 5.0.0 (installed 1.0.0)
  - suspicious_login: 11.0.0-dev.0 (installed 7.0.0)
  - systemtags: 1.23.0 (installed 1.5.0)
  - text: 7.0.0-dev.3 (installed 3.1.0)
  - twofactor_nextcloud_notification: 7.0.0
  - user_ldap: 1.24.0
  - user_status: 1.13.0 (installed 1.1.1)
  - weather_status: 1.13.0 (installed 1.0.0)

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

Additional info

No response

[thomasmerz]

After some more tries I'm currently getting no such errors again - but it's totally slow'ish: about 1,5 minutes for one single (low-res) image 😢

Due to my photos are on external storage (Hetzner Storage Box via SFTP or WebDAV) I currently suspect an ongoing issue at Hetzner regarding Storage Boxes in FSN… 🤔 But serving the same dirs mounted via sshfs on the same VPS via copyparty is very fast!

[SystemKeeper]

Can you try to apply #58431 and check if it’s better ?

[thomasmerz]

Hi @SystemKeeper , I applied the mentioned patch/change from linked PR and voila: Generating previews for all images runs much more smoother than before! (many to some images per second via SFP/WebDAV external storage) 👍🏼

[SystemKeeper]

Perfect, then I'll close here, the patch is included in the next release :)