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References: <57950.1266607550@buffalo.edu>
Date: Sat, 20 Feb 2010 06:06:15 +0800 (CST)
From: Gang Luo <lgpublic@yahoo.com.cn>
Subject: Re: Some information on Hadoop Sort
To: common-user@hadoop.apache.org, aa225@buffalo.edu
In-Reply-To: <57950.1266607550@buffalo.edu>
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Hi,=0Athe sorting is done by the MapReduce framework. At map side, the outp=
ut record will first go to a sorting buffer where the sorting, partitioning=
 and combining (if there is combiner) happen. If necessary, multi-phase sor=
ting is done to make a single sorted result for each map task. At reduce si=
de, all the data from multiple map tasks will be merged (each of them is so=
rted at the map side, you only need merge sort here). It goes multiple roun=
ds if necessary.=0A=0A-Gang=0A=0A=0A=0A----- =D4=AD=CA=BC=D3=CA=BC=FE ----=
=0A=B7=A2=BC=FE=C8=CB=A3=BA "aa225@buffalo.edu" <aa225@buffalo.edu>=0A=CA=
=D5=BC=FE=C8=CB=A3=BA common-user@hadoop.apache.org=0A=B7=A2=CB=CD=C8=D5=C6=
=DA=A3=BA 2010/2/19 (=D6=DC=CE=E5) 2:25:50 =CF=C2=CE=E7=0A=D6=F7   =CC=E2=
=A3=BA Some information on Hadoop Sort=0A=0AHello,=0A      I was wondering =
if some one could me some information on hadoop does the=0Asorting. From wh=
at I have read there does not seem to be a map class and reduce=0Aclass ? W=
here and how is the sorting parallelized ?=0A=0A=0ABest Regards from Buffal=
o=0A=0AAbhishek Agrawal=0A=0ASUNY- Buffalo=0A(716-435-7122)=0A=0A=0A      _=
__________________________________________________________ =0A  =BA=C3=CD=
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=C9=CF=CF=DF=A3=A1 =0Ahttp://card.mail.cn.yahoo.com/