private long getCacheCompactedBlocksOnWriteThreshold(Configuration conf) {
    long cacheCompactedBlocksOnWriteThreshold =
      conf.getLong(CACHE_COMPACTED_BLOCKS_ON_WRITE_THRESHOLD_KEY,
        DEFAULT_CACHE_COMPACTED_BLOCKS_ON_WRITE_THRESHOLD);

    if (cacheCompactedBlocksOnWriteThreshold < 0) {
      LOG.warn(
        "cacheCompactedBlocksOnWriteThreshold value : {} is less than 0, resetting it to: {}",
        cacheCompactedBlocksOnWriteThreshold, DEFAULT_CACHE_COMPACTED_BLOCKS_ON_WRITE_THRESHOLD);
      cacheCompactedBlocksOnWriteThreshold = DEFAULT_CACHE_COMPACTED_BLOCKS_ON_WRITE_THRESHOLD;
    }

    return cacheCompactedBlocksOnWriteThreshold;
  }
Returns the block cache.
@return the block cache, or null if caching is completely disabled
hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/CacheConfig.java