Method 'clear_variability' renamed to 'clear_modified'.
Redis server updates only updated data, if you change the metadata, not all of the metadata.
Change the 'completed' attribute sets 'failed' to 0, the change 'failed' sets 'completed' to 0. The attributes 'completed' and 'failed' are mutually exclusive.
Method 'update_job' accesses the Redis server only if there is some data to update. FIXES:
$@ is localized before we attempt to catch an exception.