FAQ
Hi,
Which file contains all this code ? I am looking at the file TeraSort.java but
this contains code for creating a trie. Similarly the file MergeSort.java
contains code for simple sequential merge sort. Where is this map reduce code ?


Best Regards from Buffalo

Abhishek Agrawal

SUNY- Buffalo
(716-435-7122)

On Fri 02/19/10 5:06 PM , Gang Luo lgpublic@yahoo.com.cn sent:
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



----- ���件 ----
�件人� "aa225@buffa
lo.edu" <aa225@buffa
lo.edu>�件人� common-user@hadoop.apache.org����� 2010/2/19
(��) 2:25:50 ��主 �� Some information on
Hadoop Sort
Hello,
I was wondering if some one could me some information on hadoop does
thesorting. From what I have read there does not seem to be a map class and
reduceclass ? Where and how is the sorting parallelized ?


Best Regards from Buffalo

Abhishek Agrawal

SUNY- Buffalo
(716-435-7122)


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