Remove Non-Existent Background Jobs

Introduction

During the lifecycle of ownCloud, some background jobs may get removed as they are either superseded by another job or completely obsolete. It can also happen, that an app providing a background job was removed and the job therefore is no longer present. These jobs can be removed manually.

Identification

If the ownCloud log files contain errors like:

"Exception: {"Exception":"OCP\AppFramework\QueryException","Message":"Could not resolve OCA\User_LDAP\Jobs\UpdateGroups! Class OCA\User_LDAP\Jobs\UpdateGroups does not exist","Code":0,"Trace":"

"Exception: {"Exception":"OCP\AppFramework\QueryException","Message":"Could not resolve OCA\User_LDAP\Jobs\CleanUp! Class OCA\User_LDAP\Jobs\CleanUp does not exist","Code":0,"Trace":"

"Exception: {"Exception":"OCP\AppFramework\QueryException","Message":"Could not resolve OCA\Federation\SyncJob! Class OCA\Federation\SyncJob does not exist","Code":0,"Trace":"

these background jobs can safely be removed as they no longer exist.

Removal Process

There is an occ command set for managing background jobs triggered by ownCloud. The following steps are necessary to remove a background job:

  1. Identify the Job-ID of the background job to be removed

  2. Remove the background job based on the Job-ID

It is also possible that a background job is triggered manually by the admin when the job has been added to eg. crontab.

Identify the Job-ID of the Background Job to Be Removed

Use the following command to list all active background jobs triggered by ownCloud:

sudo -u www-data php occ background:queue:status

The output may look like the following:

+----+---------------------------------------------------+---------------------------+---------------+
| Id | Job                                               | Last run                  | Job Arguments |
+----+---------------------------------------------------+---------------------------+---------------+
| 1  | OCA\Files\BackgroundJob\ScanFiles                 | 2022-01-23T14:00:02+00:00 |               |
| 2  | OCA\Files\BackgroundJob\DeleteOrphanedItems       | 2022-01-23T14:00:02+00:00 |               |
| 3  | OCA\Files\BackgroundJob\CleanupFileLocks          | 2022-01-23T14:00:02+00:00 |               |
| 4  | OCA\DAV\CardDAV\SyncJob                           | 2022-01-23T14:00:02+00:00 |               |
...
+----+---------------------------------------------------+---------------------------+---------------+

Remove the Background Job

When you have identified the ID of the background job to be removed, run following command to remove it, replace ID with the job number of the list:

sudo -u www-data php occ background:queue:delete ID
Deleting a job cannot be undone. Be sure that you want to delete the job before doing so.

Remove Jobs Manually Added via Crontab

If an erroring job as been added manually in crontab, remove the job from the crontab queue list. First, list the entries of crontab for the web server user:

sudo -uwww-data crontab -l

Then edit the crontab job list to remove the job by invoking following command:

sudo -uwww-data crontab -e