Hit data loss due to cache expiration before persistence

Hits stored in memcache expire after HITCOUNT_CACHE_TIMEOUT (default 600 seconds) but persistence runs every HITCOUNT_PERSIST_SCHEDULE (default 15 minutes). Hits that remain unpersisted for more than 10 minutes are lost when cache expires before the periodic persistence task runs.

Ensure HITCOUNT_PERSIST_SCHEDULE is less than HITCOUNT_CACHE_TIMEOUT to prevent data loss. Either decrease persist schedule to under 10 minutes or increase cache timeout above 15 minutes. Run 'python manage.py persist_hits' manually to force immediate persistence if data loss is suspected.