Hi, the sorting is done by the MapReduce framework. At map side, the output record will first go to a sorting buffer where the sorting, partitioning and combining (if there is combiner) happen. If necessary, multi-phase sorting is done to make a single sorted result for each map task. At reduce side, all the data from multiple map tasks will be merged (each of them is sorted at the map side, you only need merge sort here). It goes multiple rounds if necessary.
-Gang ----- 原始邮件 ---- 发件人： "[email protected]" <[email protected]> 收件人： [email protected] 发送日期： 2010/2/19 (周五) 2:25:50 下午 主 题： Some information on Hadoop Sort Hello, I was wondering if some one could me some information on hadoop does the sorting. From what I have read there does not seem to be a map class and reduce class ? Where and how is the sorting parallelized ? Best Regards from Buffalo Abhishek Agrawal SUNY- Buffalo (716-435-7122) ___________________________________________________________ 好玩贺卡等你发，邮箱贺卡全新上线！ http://card.mail.cn.yahoo.com/
