from threading import Timer
from hydrus.data.db_models import Modification
from sqlalchemy.orm import scoped_session
def remove_stale_modification_records(session: scoped_session,
stale_records_removal_interval: int=900):
"""
Remove modification records which are older than last 1000 records.
:param session: sqlalchemy session.
:param stale_records_removal_interval: Interval time to run the removal job.
"""
timer = Timer(stale_records_removal_interval,
remove_stale_modification_records, [session])
timer.daemon = True
timer.start()
# Get all valid records.
valid_records = session.query(Modification).order_by(
Modification.job_id.desc()).limit(1000).all()
# If number of returned valid records is less than set limit then
# there is nothing to clean up.
if len(valid_records) < 1000:
return
else:
# Get the job_id of last (oldest) valid record.
job_id_of_last_valid_record = valid_records[-1].job_id
# Get all records which are older than the oldest valid record.
stale_records = session.query(Modification).filter(
Modification.job_id < job_id_of_last_valid_record).all()
for record in stale_records:
session.delete(record)
session.commit()
session.remove()
