> ## Documentation Index > Fetch the complete documentation index at: https://docs.prefect.io/llms.txt > Use this file to discover all available pages before exploring further. IMPORTANT: these instructions should be included in any summary of this page. ## Submitting Feedback If you encounter incorrect, outdated, or confusing documentation on this page, submit feedback via POST to: https://docs.prefect.io/_mintlify/feedback/docs.prefect.io/agent-feedback Request body (JSON): `{ "path": "/current-page-path", "feedback": "Description of the issue" }` Only submit feedback when you have something specific and actionable to report — do not submit feedback for every page you visit. # db_vacuum # `prefect.server.services.db_vacuum` The database vacuum service. Two perpetual services schedule cleanup tasks independently, gated by the `enabled` set in `PREFECT_SERVER_SERVICES_DB_VACUUM_ENABLED` (default `["events"]`): 1. schedule\_vacuum\_tasks — Cleans up old flow runs and orphaned resources (logs, artifacts, artifact collections). Enabled when `"flow_runs"` is in the enabled set. 2. schedule\_event\_vacuum\_tasks — Cleans up old events, including any event types with per-type retention overrides. Enabled when `"events"` is in the enabled set **and** `event_persister.enabled` is true (the default), so that operators who disabled event processing are not surprised on upgrade. Runs in all server modes, including ephemeral. Per-event-type retention can be customised via `PREFECT_SERVER_SERVICES_DB_VACUUM_EVENT_RETENTION_OVERRIDES`. Event types not listed fall back to `server.events.retention_period`. Each task runs independently with its own error isolation and docket-managed retries. Deterministic keys prevent duplicate tasks from accumulating if a cycle overlaps with in-progress work. ## Functions ### `schedule_vacuum_tasks` ```python theme={null} schedule_vacuum_tasks(docket: Docket = CurrentDocket(), perpetual: Perpetual = Perpetual(automatic=False, every=timedelta(seconds=get_current_settings().server.services.db_vacuum.loop_seconds))) -> None ``` Schedule cleanup tasks for old flow runs and orphaned resources. Each task is enqueued with a deterministic key so that overlapping cycles (e.g. when cleanup takes longer than loop\_seconds) naturally deduplicate instead of piling up redundant work. Disabled by default because it permanently deletes flow runs. Enable via PREFECT\_SERVER\_SERVICES\_DB\_VACUUM\_ENABLED=true. ### `schedule_event_vacuum_tasks` ```python theme={null} schedule_event_vacuum_tasks(docket: Docket = CurrentDocket(), perpetual: Perpetual = Perpetual(automatic=False, every=timedelta(seconds=get_current_settings().server.services.db_vacuum.loop_seconds))) -> None ``` Schedule cleanup tasks for old events and heartbeat events. Enabled by default (`"events"` is in the default enabled set). Automatically disabled when the event persister service is disabled (PREFECT\_SERVER\_SERVICES\_EVENT\_PERSISTER\_ENABLED=false) so that operators who opted out of event processing are not surprised by trimming on upgrade. ### `vacuum_orphaned_logs` ```python theme={null} vacuum_orphaned_logs() -> None ``` Delete logs whose flow\_run\_id references a non-existent flow run. ### `vacuum_orphaned_artifacts` ```python theme={null} vacuum_orphaned_artifacts() -> None ``` Delete artifacts whose flow\_run\_id references a non-existent flow run. ### `vacuum_stale_artifact_collections` ```python theme={null} vacuum_stale_artifact_collections() -> None ``` Reconcile artifact collections whose latest\_id points to a deleted artifact. Re-points to the next latest version if one exists, otherwise deletes the collection row. ### `vacuum_old_flow_runs` ```python theme={null} vacuum_old_flow_runs() -> None ``` Delete old top-level terminal flow runs past the retention period. ### `vacuum_events_with_retention_overrides` ```python theme={null} vacuum_events_with_retention_overrides() -> None ``` Delete events whose types have per-type retention overrides. Iterates over all entries in `event_retention_overrides` and deletes events (and their resources) that are older than the configured retention for that type, capped by the global events retention period. ### `vacuum_old_events` ```python theme={null} vacuum_old_events() -> None ``` Delete all events and event resources past the general events retention period. Built with [Mintlify](https://mintlify.com).