Likely caused by corruption in database "QLogs". As this database is for centralized logging only, dropping it should not affect Qlik Sense's functionality. The exact mechanism / cause / trigger is unknown at the moment.
Please review the supported method of purging the database as documented on the Qlik Help Site.
The database admin can use the manual purge option offered through the Qlik Logging Service.
Open a command prompt with administrator privileges.
Go to C:\Program Files\Qlik\Sense\Logging.
Run Qlik.Logging.Service.exe archive --cutoff X (where X is the number of days).
Run Qlik.Logging.Service.exe purge --cutoff X (where X is the number of days, Specify zero to purge all the entries.).
If presented with a message stating the system is too busy, retry the command.
If the second try generates the same message, try again at a less busy time on the server.
Restart the Qlik Logging Service.
NOTE: Purging log entries: Purges all the archived log entries that are older than specified cutoff. Usage: Qlik.Logging.Service.exe purge [<options>] OPTIONS --cutoff or -c (Required) cutoff in days; unless the --hours option is used in which case the value is interpreted as hours. Specify zero to purge all the entries. --hours (Optional) Causes the value given for the purge cutoff (--cutoff) to be interpreted as hours instead of the default interpretation as days
Should this method not be possible, the database could be entirely dropped. Note that logging still takes place on disk and is archived to a central folder, so no loss of data logging is expected from this step. If you wish to leave the logging database off after this, be sure to stop the logging service on each node in the environment. Otherwise, follow the steps below to re-set it up.
Follow these steps:
Backup first. Either use pg_dump.exe command or, in the case of Virtual Machine, do a full snapshot of the machine.