Hive query execution issue

Question

When executing a hive query, here is the output, wondering for "Map 1" and "Reducer 2", what does the 1 and 2 mean?

Map 1: 21/27    Reducer 2: 0/1
Map 1: 22/27    Reducer 2: 0/1
Map 1: 23/27    Reducer 2: 0/1
Map 1: 24/27    Reducer 2: 0/1
Map 1: 26/27    Reducer 2: 0/1
Map 1: 27/27    Reducer 2: 0/1
Map 1: 27/27    Reducer 2: 1/1

thanks in advance, Lin

Answer 1

The hive query is interpreted by the MapReduce framework as a Map-Reduce task. The task gets assigned mappers and reducers based on the input. When the task is in progress you can see the output displayed in terms of mappers and reducers progress.