Thanks very much, Chris! Cheers, John
-----Original Message----- From: Chris Douglas [mailto:[EMAIL PROTECTED] Sent: Friday, August 08, 2008 1:57 PM To: core-user@hadoop.apache.org Subject: Re: "Join" example The contrib/data_join framework is different from the map-side join framework, under o.a.h.mapred.join. To see what the example is doing in an outer join, generate a few sample, text input files, tab-separated: join/a.txt: AAAAAAAA a0 BBBBBBBB a1 CCCCCCCC a2 CCCCCCCC a3 join/b.txt: AAAAAAAA b0 BBBBBBBB b1 BBBBBBBB b2 BBBBBBBB b3 join/c.txt: AAAAAAAA c0 BBBBBBBB c1 DDDDDDDD c2 DDDDDDDD c3 Run the example with each as an input: host$ bin/hadoop jar hadoop-*-examples.jar join \ -inFormat org.apache.hadoop.mapred.KeyValueTextInputFormat \ -outKey org.apache.hadoop.io.Text \ -joinOp outer \ join/a.txt join/b.txt join/c.txt joinout Examine the result in joinout/part-00000: host$ bin/hadoop fs -text joinout/part-00000 | less AAAAAAAA [a0,b0,c0] BBBBBBBB [a1,b1,c1] BBBBBBBB [a1,b2,c1] BBBBBBBB [a1,b3,c1] CCCCCCCC [a2,,] CCCCCCCC [a3,,] DDDDDDDD [,,c2] DDDDDDDD [,,c3] -C On Aug 7, 2008, at 11:39 PM, Wei Wu wrote: > There are some examples in $HADOOPHOME/src/contrib/data_join, which > I hope > would help. > > Wei > > -----Original Message----- > From: John DeTreville [mailto:[EMAIL PROTECTED] > Sent: Friday, August 08, 2008 2:34 AM > To: core-user@hadoop.apache.org > Subject: "Join" example > > Hadoop ships with a few example programs. One of these is "join," > which > I believe demonstrates map-side joins. I'm finding its usage > instructions a little impenetrable; could anyone send me instructions > that are more like "type this" then "type this" then "type this"? > > Thanks in advance. > > Cheers, > John >
