public double getAverageLoadPenalty() {
    return lruCache.stats().averageLoadPenalty();
  }
This class is used to cache <code>TimeSeriesMetadata</code> in IoTDB. The caching strategy is
LRU.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/buffer/TimeSeriesMetadataCache.java