这是快速排序，之后排序的中间输出合并在一起.快速排序检查递归深度并在它太深时放弃.如果是这种情况，则使用堆排序.

It's Quicksort, afterwards the sorted intermediate outputs get merged together. Quicksort checks the recursion depth and gives up when it is too deep. If this is the case, Heapsort is used.

看看 Quicksort 类:

Have a look at the Quicksort class:

org.apache.hadoop.util.QuickSort

您可以通过 hadoop-default.xml.