Hi, You would find it easier to use the Java API's MultipleOutputs (and/or MultipleOutputFormat, which directly works on a configured key field), to write each key-partition out in its own file.
On Mon, Feb 20, 2012 at 7:38 AM, Piyush Kansal <piyush.kan...@gmail.com> wrote: > Hi Friends, > > I have to sort huge amount of data in minimum possible time probably using > partitioning. The key is composed of 3 fields(partition, text and number). > This is how partition is defined: > > Partition "1" for range 1-10 > Partition "2" for range 11-20 > Partition "3" for range 21-30 > > I/P file format: partition[tab]text[tab]range-start[tab]range-end > > [cloudera@localhost kMer2]$ cat input1 > > 1 chr1 1 10 > 1 chr1 2 8 > 2 chr1 11 18 > > [cloudera@localhost kMer2]$ cat input2 > > 1 chr1 3 7 > 2 chr1 12 19 > > [cloudera@localhost kMer2]$ cat input3 > > 3 chr1 22 30 > > [cloudera@localhost kMer2]$ cat input4 > > 3 chr1 22 30 > 1 chr1 9 10 > 2 chr1 15 16 > > Then I ran following command: > > hadoop jar > /usr/lib/hadoop/contrib/streaming/hadoop-streaming-0.20.2-cdh3u2.jar \ > -D stream.map.output.field.separator='\t' \ > -D stream.num.map.output.key.fields=3 \ > -D map.output.key.field.separator='\t' \ > -D mapred.text.key.partitioner.options=-k1 \ > -D mapred.reduce.tasks=3 \ > -input /usr/pkansal/kMer2/ip \ > -output /usr/pkansal/kMer2/op \ > -mapper /home/cloudera/kMer2/kMer2Map.py \ > -file /home/cloudera/kMer2/kMer2Map.py \ > -reducer /home/cloudera/kMer2/kMer2Red.py \ > -file /home/cloudera/kMer2/kMer2Red.py > > Both mapper and reducer scripts just contain one line of code: > > for line in sys.stdin: > line = line.strip() > print "%s" % (line) > > Following is the o/p: > > [cloudera@localhost kMer2]$ hadoop dfs -cat /usr/pkansal/kMer2/op/part-00000 > > 2 chr1 12 19 > 2 chr1 15 16 > 3 chr1 22 30 > 3 chr1 22 30 > > [cloudera@localhost kMer2]$ hadoop dfs -cat /usr/pkansal/kMer2/op/part-00001 > > 1 chr1 2 8 > 1 chr1 3 7 > 1 chr1 9 10 > 2 chr1 11 18 > > [cloudera@localhost kMer2]$ hadoop dfs -cat /usr/pkansal/kMer2/op/part-00002 > > 1 chr1 1 10 > 3 chr1 22 29 > > This is not the o/p which I expected. I expected all records with: > > partition 1 in one single file eg part-m-00000 > partition 2 in one single file eg part-m-00001 > partition 3 in one single file eg part-m-00002 > > Can you please suggest if I am doing it in a right way? > > -- > Regards, > Piyush Kansal > -- Harsh J Customer Ops. Engineer Cloudera | http://tiny.cloudera.com/about
