我们知道在mapper阶段之前，文件被分割，recordreader开始向mapper发出输入。我的问题是reducer是否使用recordreader类来读取Map器发出的数据？因为减速机也需要输入！！请解释！！！
cqoc49vn1#
mapreduce步骤概述如下
1) InputFormat : - Validates the Input. - Splits the input files. - Gives Record Reader Implementation to give input to Mapper.2)Mapper Phase3)Shuffle and Sort Phase4)Reducer Phase5) OutputFormat - Validates the Output Specification. - Provides Record Writer Implementation used to write the output files.
1) InputFormat :
- Validates the Input.
- Splits the input files.
- Gives Record Reader Implementation to give input to Mapper.
2)Mapper Phase
3)Shuffle and Sort Phase
4)Reducer Phase
5) OutputFormat
- Validates the Output Specification.
- Provides Record Writer Implementation used to write the output files.
reducer不使用记录读取器。。。
1条答案
按热度按时间cqoc49vn1#
mapreduce步骤概述如下
reducer不使用记录读取器。。。