text: -- Name: BackgroundersByDateRange
  -- Schema: posda_files
  -- Columns: ['operation_name', 'num_invocations']
  -- Args: ['from', 'to']
  -- Tags: ['invoking_user']
  -- Description: Get a list of collections and sites
  -- 
  
  select
    distinct operation_name, count(distinct subprocess_invocation_id) as num_invocations
  from
    background_subprocess natural join subprocess_invocation
  where
    when_script_ended is not null and operation_name is not null and
    when_script_started > ? and when_script_ended < ? and
    when_script_ended is not null
  group by operation_name
  order by num_invocations desc