[enhancement]: Automated deletion of completed instances after n days

[rallen2010]

Feature description

We've added automations for purging process instance archives and process statistics after fixed periods. Our assumption had been that administrators would delete completed processes themselves - but maybe we should also create an automation to delete completed or terminated process instances after a configurable number of days. Would be fairly simple to add.

Describe alternatives you've considered

No response

Additional context

No response

[rallen2010]

We could have a instance_retention_period (in days) then have an automation that deletes process instances where
prcs_complete_ts < systimestamp - instance_retention_period. The instance completion is currently stored as a timestamp for each instance (prcs_complete_ts) and records completion for normal and termination completions.

Simplest option would be to have this as a system wide parameter, stored in flow_configurations.

More elaborate solution would be to allow a diagram-level parameter, stored for each diagram in a new column in flow_diagrams. say dgrm_process_retention. If this is not specified, the system wide parameter would be used.

Updated - July 2024 - Changed parameter from 'retention_period to instance_retention_period in case we want to do anything separate for tasks in future...