boolean isChunkInPool(int chunkId) {
    Chunk c = getChunk(chunkId);
    if (c == null) {
      return false;
    }

    // chunks that are from pool will return true chunk reference not null
    if (dataChunksPool != null && dataChunksPool.reclaimedChunks.contains(c)) {
      return true;
    } else if (indexChunksPool != null && indexChunksPool.reclaimedChunks.contains(c)) {
      return true;
    }
    return false;
  }
Add the chunks to the pool, when the pool achieves the max size, it will skip the remaining
chunks
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/ChunkCreator.java