The "Background Schedulers" screen registers and changes background schedulers. A background scheduler is a process that executes the background jobs requested by users. These jobs are based on [[Invantive Estate/Subjects/Advanced/Background Scripts|Background Scripts]]. The entry fields are: - "Code": The unique code. - "Description": The description. - "Activation Interval": The time in seconds between checks for jobs that are ready to start. A background scheduler that is not executing a job performs these checks regularly. - "Category": The skills that the scheduler offers. A [[Invantive Estate/Subjects/Advanced/Background Scripts|Background Script]] can only run on schedulers that have the required skills. - "Activate on Startup": When checked, the scheduler activates when the web server starts. The other fields are: - "Status": The status of the background scheduler. The possible statuses follow after this list. - "Database Session": The unique database session that belongs to this background scheduler. - "Java Object": The Java object that the background scheduler executes. - "Machine": The machine on which the background scheduler runs. - "Last Installed": The system time at which the background scheduler was last installed. - "Last Message": The last message of the scheduler. - "Old Messages": The earlier values of the last message that the scheduler gave. The field "Status" has these values: - Off: the background scheduler is not activated while starting the web server. - Initialising: the background scheduler is being initialised, but is not active yet. This status only occurs for a short moment while starting the web server. - Active: the background scheduler is actively checking whether there are background jobs to start. - Executing: the background scheduler is currently executing a background job. - Sleeping mode: the background scheduler sleeps until the end of the activation interval. - Error: the background scheduler is in error mode. Monitoring tools such as Probe also show the background schedulers, as threads in Apache Tomcat.