我在sparkshell中编写了一个Dataframe到hdfs中，得到了下面的输出。我想了解的是，是什么决定了正在编写的Parquet文件的大小？my dfs.block.size设置为：

scala> spark.sparkContext.hadoopConfiguration.get("dfs.block.size")
res1: String = 134217728

这是128mb，那么为什么我的文件在20000000字节的范围内呢？

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