core/homeassistant/components/recorder/purge.py

71 lines
2.7 KiB
Python

"""Purge old data helper."""
from datetime import timedelta
import logging
import homeassistant.util.dt as dt_util
from .util import session_scope
_LOGGER = logging.getLogger(__name__)
def purge_old_data(instance, purge_days, repack):
"""Purge events and states older than purge_days ago."""
from .models import States, Events
from sqlalchemy import func
purge_before = dt_util.utcnow() - timedelta(days=purge_days)
_LOGGER.debug("Purging events before %s", purge_before)
with session_scope(session=instance.get_session()) as session:
delete_states = session.query(States) \
.filter((States.last_updated < purge_before))
# For each entity, the most recent state is protected from deletion
# s.t. we can properly restore state even if the entity has not been
# updated in a long time
protected_states = session.query(func.max(States.state_id)) \
.group_by(States.entity_id).all()
protected_state_ids = tuple(state[0] for state in protected_states)
if protected_state_ids:
delete_states = delete_states \
.filter(~States.state_id.in_(protected_state_ids))
deleted_rows = delete_states.delete(synchronize_session=False)
_LOGGER.debug("Deleted %s states", deleted_rows)
delete_events = session.query(Events) \
.filter((Events.time_fired < purge_before))
# We also need to protect the events belonging to the protected states.
# Otherwise, if the SQL server has "ON DELETE CASCADE" as default, it
# will delete the protected state when deleting its associated
# event. Also, we would be producing NULLed foreign keys otherwise.
if protected_state_ids:
protected_events = session.query(States.event_id) \
.filter(States.state_id.in_(protected_state_ids)) \
.filter(States.event_id.isnot(None)) \
.all()
protected_event_ids = tuple(state[0] for state in protected_events)
if protected_event_ids:
delete_events = delete_events \
.filter(~Events.event_id.in_(protected_event_ids))
deleted_rows = delete_events.delete(synchronize_session=False)
_LOGGER.debug("Deleted %s events", deleted_rows)
# Execute sqlite vacuum command to free up space on disk
_LOGGER.debug("DB engine driver: %s", instance.engine.driver)
if repack and instance.engine.driver == 'pysqlite':
from sqlalchemy import exc
_LOGGER.debug("Vacuuming SQLite to free space")
try:
instance.engine.execute("VACUUM")
except exc.OperationalError as err:
_LOGGER.error("Error vacuuming SQLite: %s.", err)