db.py 文件源码

def get_cached_multiple_link_load(items, time_interval):
    """Cached version of get_multiple_link_load()"""
    item_map = {k: _cache_key(k, time_interval) for k in iterkeys(items)}
    # cache lookup
    cached = cache.get_many(item_map.values())
    _logger.debug(
        "get_cached_multiple_link_load: got %d/%d values from cache (%r)",
        len(cached), len(items), time_interval)

    # retrieve data for cache misses
    misses = {k: v
              for k, v in iteritems(items) if item_map[k] not in cached}
    if misses:
        get_multiple_link_load(misses, time_interval)

    # set data from cache
    reverse_item_map = {v: k for k, v in iteritems(item_map)}
    for cache_key, value in iteritems(cached):
        key = reverse_item_map[cache_key]
        properties = items[key]
        properties['load_in'], properties['load_out'] = value

    # add new data to cache
    missed_data = {item_map[key]: (properties['load_in'],
                                   properties['load_out'])
                   for key, properties in iteritems(misses)}
    _logger.debug("get_cached_multiple_link_load: caching %d values",
                  len(missed_data))
    cache.set_many(missed_data, CACHE_TIMEOUT)