[Bug]: "too many connections" database error when restoring lots of deleted files via web ui

⚠️ 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

Server becomes unresponsive for a while when attempting to restore many deleted files on the web ui. Based on the logs, it seems the server is opening a new database connection for each file at the same time, which the database refuses with "too many connections".

The server becomes responsive again after a while, but not all files will have been restored.

Steps to reproduce

1. (accidentally) delete lots of files, e.g. 500 (to be safe, make sure you delete 500 files and not just a directory containing 500 files)
2. Go to "Deleted files" on web ui, select all files and click on "Restore"
3. Notice how Nextcloud client loses connection to server and web ui freezes; refreshing the page returns "internal server error"
4. Wait a couple of minutes until server responds again
5. Check "Deleted files" and notice that some, but not all files have been restored

PS: The bug may be easier to reproduce on weaker hardware. For the record, my server was a Synology DS918+ with 4GB RAM and SSD cache.

Expected behavior

The server should remain responsive at all times even when restoring hundreds of deleted files via web ui. It also should restore all selected files and not just some of them.

Nextcloud Server version

31

Operating system

Other

PHP engine version

PHP 8.3

Web server

Apache (supported)

Database engine version

PostgreSQL

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

Fresh Nextcloud Server install

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": {
        "one-click-instance": true,
        "one-click-instance.user-limit": 100,
        "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
            }
        ],
        "check_data_directory_permissions": false,
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "password": "***REMOVED SENSITIVE VALUE***",
            "port": 6379
        },
        "overwritehost": "***REDACTED***",
        "overwriteprotocol": "https",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "localhost",
            "***REDACTED***"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "pgsql",
        "version": "31.0.8.1",
        "overwrite.cli.url": "https:\/\/***REDACTED***\/",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "maintenance": false,
        "updatechecker": false,
        "loglevel": 3,
        "log_type": "file",
        "logfile": "\/var\/www\/html\/data\/nextcloud.log",
        "log_rotate_size": 10485760,
        "log.condition": {
            "apps": [
                "admin_audit"
            ]
        },
        "preview_max_x": 2048,
        "preview_max_y": 2048,
        "jpeg_quality": 60,
        "enabledPreviewProviders": {
            "1": "OC\\Preview\\Image",
            "2": "OC\\Preview\\MarkDown",
            "3": "OC\\Preview\\MP3",
            "4": "OC\\Preview\\TXT",
            "5": "OC\\Preview\\OpenDocument",
            "6": "OC\\Preview\\Movie",
            "7": "OC\\Preview\\Krita",
            "0": "OC\\Preview\\Imaginary",
            "23": "OC\\Preview\\ImaginaryPDF"
        },
        "enable_previews": true,
        "upgrade.disable-web": true,
        "mail_smtpmode": "smtp",
        "trashbin_retention_obligation": "auto, 30",
        "versions_retention_obligation": "auto, 30",
        "activity_expire_days": 30,
        "simpleSignUpLink.shown": false,
        "share_folder": "\/Shared",
        "one-click-instance.link": "https:\/\/nextcloud.com\/all-in-one\/",
        "upgrade.cli-upgrade-link": "https:\/\/github.com\/nextcloud\/all-in-one\/discussions\/2726",
        "updatedirectory": "\/nc-updater",
        "maintenance_window_start": 100,
        "allow_local_remote_servers": true,
        "davstorage.request_timeout": 3600,
        "documentation_url.server_logs": "https:\/\/github.com\/nextcloud\/all-in-one\/discussions\/5425",
        "htaccess.RewriteBase": "\/",
        "dbpersistent": false,
        "auth.bruteforce.protection.enabled": true,
        "ratelimit.protection.enabled": true,
        "files_external_allow_create_new_local": true,
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "preview_imaginary_url": "***REMOVED SENSITIVE VALUE***",
        "preview_imaginary_key": "***REMOVED SENSITIVE VALUE***",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_sendmailmode": "smtp",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "587",
        "mail_smtpauth": true,
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "default_phone_region": "***REDACTED***"
    }
}

List of activated Apps

Enabled:
  - activity: 4.0.0
  - admin_audit: 1.21.0
  - bruteforcesettings: 4.0.0
  - circles: 31.0.0
  - cloud_federation_api: 1.14.0
  - comments: 1.21.0
  - contactsinteraction: 1.12.0
  - dashboard: 7.11.0
  - dav: 1.33.0
  - federatedfilesharing: 1.21.0
  - federation: 1.21.0
  - files: 2.3.1
  - files_downloadlimit: 4.0.0
  - files_external: 1.23.0
  - files_pdfviewer: 4.0.0
  - files_reminders: 1.4.0
  - files_sharing: 1.23.1
  - files_trashbin: 1.21.0
  - files_versions: 1.24.0
  - firstrunwizard: 4.0.0
  - logreader: 4.0.0
  - lookup_server_connector: 1.19.0
  - nextcloud-aio: 0.8.0
  - nextcloud_announcements: 3.0.0
  - notifications: 4.0.0
  - notify_push: 1.2.0
  - oauth2: 1.19.1
  - password_policy: 3.0.0
  - photos: 4.0.0
  - privacy: 3.0.0
  - profile: 1.0.0
  - provisioning_api: 1.21.0
  - recommendations: 4.0.0
  - related_resources: 2.0.0
  - serverinfo: 3.0.0
  - settings: 1.14.0
  - sharebymail: 1.21.0
  - support: 3.0.0
  - survey_client: 3.0.0
  - systemtags: 1.21.1
  - text: 5.0.0
  - theming: 2.6.1
  - twofactor_backupcodes: 1.20.0
  - twofactor_totp: 13.0.0-dev.0
  - updatenotification: 1.21.0
  - user_status: 1.11.0
  - viewer: 4.0.0
  - weather_status: 1.11.0
  - webhook_listeners: 1.2.0
  - workflowengine: 2.13.0
Disabled:
  - app_api: 5.0.2 (installed 5.0.2)
  - encryption: 2.19.0
  - suspicious_login: 9.0.1
  - twofactor_nextcloud_notification: 5.0.0
  - user_ldap: 1.22.0

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

{"reqId":"FqZX9BzTUMOLKNKB8e4g","level":3,"time":"2025-09-04T10:17:16+00:00","remoteAddr":"82.136.69.152","user":"--","app":"core","method":"MOVE","url":"/remote.php/dav/trashbin/***REDACTED***/trash/***REDACTED***.pdf.d1756978385","message":"Failed to connect to the database: An exception occurred in the driver: SQLSTATE[08006] [7] connection to server at \"nextcloud-aio-database\" (172.21.0.4), port 5432 failed: FATAL:  sorry, too many clients already","userAgent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/139.0.0.0 Safari/537.36 Edg/139.0.0.0","version":"31.0.8.1","exception":{"Exception":"Doctrine\\DBAL\\Exception","Message":"Failed to connect to the database: An exception occurred in the driver: SQLSTATE[08006] [7] connection to server at \"nextcloud-aio-database\" (172.21.0.4), port 5432 failed: FATAL:  sorry, too many clients already","Code":7,"Trace":[{"file":"/var/www/html/3rdparty/doctrine/dbal/src/Connection.php","line":458,"function":"connect","class":"OC\\DB\\Connection","type":"->","args":[]},{"file":"/var/www/html/3rdparty/doctrine/dbal/src/Connection.php","line":416,"function":"getDatabasePlatformVersion","class":"Doctrine\\DBAL\\Connection","type":"->","args":[]},{"file":"/var/www/html/3rdparty/doctrine/dbal/src/Connection.php","line":323,"function":"detectDatabasePlatform","class":"Doctrine\\DBAL\\Connection","type":"->","args":[]},{"file":"/var/www/html/lib/private/DB/Connection.php","line":903,"function":"getDatabasePlatform","class":"Doctrine\\DBAL\\Connection","type":"->","args":[]},{"file":"/var/www/html/lib/private/DB/ConnectionAdapter.php","line":235,"function":"getDatabaseProvider","class":"OC\\DB\\Connection","type":"->","args":[]},{"file":"/var/www/html/lib/private/DB/QueryBuilder/QueryBuilder.php","line":96,"function":"getDatabaseProvider","class":"OC\\DB\\ConnectionAdapter","type":"->","args":[]},{"file":"/var/www/html/lib/private/AppConfig.php","line":1253,"function":"expr","class":"OC\\DB\\QueryBuilder\\QueryBuilder","type":"->","args":[]},{"file":"/var/www/html/lib/private/AppConfig.php","line":270,"function":"loadConfig","class":"OC\\AppConfig","type":"->","args":[null,false]},{"file":"/var/www/html/lib/private/AppConfig.php","line":1393,"function":"searchValues","class":"OC\\AppConfig","type":"->","args":["enabled",false,2]},{"file":"/var/www/html/lib/private/App/AppManager.php","line":136,"function":"getValues","class":"OC\\AppConfig","type":"->","args":[false,"enabled"]},{"file":"/var/www/html/lib/private/App/AppManager.php","line":157,"function":"getInstalledAppsValues","class":"OC\\App\\AppManager","type":"->","args":[]},{"file":"/var/www/html/lib/private/legacy/OC_App.php","line":188,"function":"getInstalledApps","class":"OC\\App\\AppManager","type":"->","args":[]},{"file":"/var/www/html/lib/private/AppFramework/Bootstrap/Coordinator.php","line":48,"function":"getEnabledApps","class":"OC_App","type":"::","args":[]},{"file":"/var/www/html/lib/base.php","line":676,"function":"runInitialRegistration","class":"OC\\AppFramework\\Bootstrap\\Coordinator","type":"->","args":[]},{"file":"/var/www/html/lib/base.php","line":1192,"function":"init","class":"OC","type":"::","args":[]},{"file":"/var/www/html/remote.php","line":91,"args":["/var/www/html/lib/base.php"],"function":"require_once"}],"File":"/var/www/html/lib/private/DB/Connection.php","Line":237,"message":"Failed to connect to the database: An exception occurred in the driver: SQLSTATE[08006] [7] connection to server at \"nextcloud-aio-database\" (172.21.0.4), port 5432 failed: FATAL:  sorry, too many clients already","exception":{},"CustomMessage":"Failed to connect to the database: An exception occurred in the driver: SQLSTATE[08006] [7] connection to server at \"nextcloud-aio-database\" (172.21.0.4), port 5432 failed: FATAL:  sorry, too many clients already"}}
{"reqId":"FqZX9BzTUMOLKNKB8e4g","level":3,"time":"2025-09-04T10:17:16+00:00","remoteAddr":"82.136.69.152","user":"--","app":"core","method":"MOVE","url":"/remote.php/dav/trashbin/***REDACTED***/trash/***REDACTED***.pdf.d1756978385","message":"Failed to connect to the database: An exception occurred in the driver: SQLSTATE[08006] [7] connection to server at \"nextcloud-aio-database\" (172.21.0.4), port 5432 failed: FATAL:  remaining connection slots are reserved for roles with the SUPERUSER attribute","userAgent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/139.0.0.0 Safari/537.36 Edg/139.0.0.0","version":"31.0.8.1","exception":{"Exception":"Doctrine\\DBAL\\Exception","Message":"Failed to connect to the database: An exception occurred in the driver: SQLSTATE[08006] [7] connection to server at \"nextcloud-aio-database\" (172.21.0.4), port 5432 failed: FATAL:  remaining connection slots are reserved for roles with the SUPERUSER attribute","Code":7,"Trace":[{"file":"/var/www/html/3rdparty/doctrine/dbal/src/Connection.php","line":458,"function":"connect","class":"OC\\DB\\Connection","type":"->","args":[]},{"file":"/var/www/html/3rdparty/doctrine/dbal/src/Connection.php","line":416,"function":"getDatabasePlatformVersion","class":"Doctrine\\DBAL\\Connection","type":"->","args":[]},{"file":"/var/www/html/3rdparty/doctrine/dbal/src/Connection.php","line":323,"function":"detectDatabasePlatform","class":"Doctrine\\DBAL\\Connection","type":"->","args":[]},{"file":"/var/www/html/lib/private/DB/Connection.php","line":903,"function":"getDatabasePlatform","class":"Doctrine\\DBAL\\Connection","type":"->","args":[]},{"file":"/var/www/html/lib/private/DB/ConnectionAdapter.php","line":235,"function":"getDatabaseProvider","class":"OC\\DB\\Connection","type":"->","args":[]},{"file":"/var/www/html/lib/private/DB/QueryBuilder/QueryBuilder.php","line":96,"function":"getDatabaseProvider","class":"OC\\DB\\ConnectionAdapter","type":"->","args":[]},{"file":"/var/www/html/lib/private/AppConfig.php","line":1253,"function":"expr","class":"OC\\DB\\QueryBuilder\\QueryBuilder","type":"->","args":[]},{"file":"/var/www/html/lib/private/AppConfig.php","line":270,"function":"loadConfig","class":"OC\\AppConfig","type":"->","args":[null,false]},{"file":"/var/www/html/lib/private/legacy/OC_App.php","line":653,"function":"searchValues","class":"OC\\AppConfig","type":"->","args":["installed_version"]},{"file":"/var/www/html/lib/private/TemplateLayout.php","line":202,"function":"getAppVersions","class":"OC_App","type":"::","args":[]},{"file":"/var/www/html/lib/private/legacy/OC_Template.php","line":120,"function":"__construct","class":"OC\\TemplateLayout","type":"->","args":["error",""]},{"file":"/var/www/html/lib/private/Template/Base.php","line":113,"function":"fetchPage","class":"OC_Template","type":"->","args":[]},{"file":"/var/www/html/lib/private/legacy/OC_Template.php","line":297,"function":"printPage","class":"OC\\Template\\Base","type":"->","args":[]},{"file":"/var/www/html/remote.php","line":60,"function":"printExceptionErrorPage","class":"OC_Template","type":"::","args":[{"__class__":"Doctrine\\DBAL\\Exception"},500]},{"file":"/var/www/html/remote.php","line":147,"function":"handleException","args":[{"__class__":"Doctrine\\DBAL\\Exception"}]}],"File":"/var/www/html/lib/private/DB/Connection.php","Line":237,"message":"Failed to connect to the database: An exception occurred in the driver: SQLSTATE[08006] [7] connection to server at \"nextcloud-aio-database\" (172.21.0.4), port 5432 failed: FATAL:  remaining connection slots are reserved for roles with the SUPERUSER attribute","exception":{},"CustomMessage":"Failed to connect to the database: An exception occurred in the driver: SQLSTATE[08006] [7] connection to server at \"nextcloud-aio-database\" (172.21.0.4), port 5432 failed: FATAL:  remaining connection slots are reserved for roles with the SUPERUSER attribute"}}

Additional info

Nextcloud server installed on Synology NAS via Docker via Nextcloud AIO

Reproduce the web UI restore of hundreds of deleted files, then trace the MOVE request from remote.php through lib/private/DB/Connection.php, ConnectionAdapter.php, QueryBuilder/QueryBuilder.php, and AppConfig.php. Use the PostgreSQL error and the listed stack trace as the starting evidence; done means all selected files restore while the server remains responsive without exhausting database connections.