Tracker timestamps map

This quick map summarizes which tracker timestamp fields are updated by which services and how they are used in the fetch + geofence pipelines.

Summary table

Field	Updated by	Used by	Primary purpose	Notes
`last_report_received`	`services/tracker_fetcher_2/taskiq_service.py` (`_update_last_report_received`)	`app/api/routes/trackers/listing.py`, `app/crud/tracker.py`	Track the latest report timestamp per tracker	Used for listing sort/filter and "active trackers" query.
`last_processed_at`	`services/tracker_fetcher_2/taskiq_service.py` (`_update_tracker_processed_timestamp`), `services/unified_geofence_service/taskiq_service.py` (`_update_tracking_fields`)	Fetcher queue logic	Fair scheduling and staleness tracking	Used for batch ordering and queue scoring.
`last_status_check`	`services/tracker_status_service/service.py` (status updates), `services/unified_geofence_service/taskiq_service.py` (`_update_tracking_fields`)	`services/tracker_status_service/service.py`	Track when status was last evaluated	Used to skip reprocessing older location data.
`current_state_start`	`services/tracker_status_service/service.py`, `services/unified_geofence_service/taskiq_service.py`	Analytics + status history	When the current status began	Set to triggering location timestamp.
`last_report_requested`	No current writers found	No current readers found	Legacy or future use	Field exists in model/schema; not referenced in services.
`last_position_report`	No current writers found	No current readers found	Legacy or future use	Field exists in model/schema; not referenced in services.

Pipeline sketch (text diagram)

FindMy fetcher (tracker_fetcher_2)
  -> inserts location_reports
  -> updates trackers.last_report_received
  -> updates trackers.last_processed_at (fair scheduling)
  -> schedules unified geofence processing

Unified geofence service
  -> reads location_reports
  -> determines tracker status + geofence events
  -> updates trackers.current_status, current_state_start
  -> updates trackers.last_status_check, last_processed_at
  -> writes status_history + geofence_events

Tracker status service (legacy batch path)
  -> reads location_history (materialized view)
  -> updates trackers.current_status, current_state_start
  -> updates trackers.last_status_check
  -> writes status_history

Key takeaways

Operationally active fields: last_report_received, last_processed_at, last_status_check, current_state_start.
last_report_requested and last_position_report appear unused in current services.