How many tags you have? If you have several number of tags, you'd better
create a Vector class to hold those tags. And define sum function to
increment the values of tags. Then the value class should be your new
Vector class. That's better and more decent than the Textpair approach.
Shi
On 2010-10-18 5:19, Matthew John wrote:
Hi all,
I had a small doubt regarding the reduce module. What I understand is that
after the shuffle / sort phase , all the records with the same key value
goes into a reduce function. If thats the case, what is the attribute of the
Writable key which ensures that all the keys go to the same reduce ?
I am working on a reduce side Join where I need to tag all the keys with a
bit which might vary but still want all those records to go into same
reduce. In Hadoop the Definitive Guide, pg. 235 they are using TextPair for
the key. But I dont understand how the keys with different tag information
goes into the same reduce.
Matthew
