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Posted to common-user@hadoop.apache.org by Andreas Kostyrka <an...@kostyrka.org> on 2008/06/06 17:07:27 UTC

key assignment to reducers

Hi!

I just wondered what semantics I can rely on concerning reducing:

-) All key/value pairs with a given key end up in the same reducer.

-) What I now wonder, do all key/value pairs for a given key end up in one 
sequence?

So basically, do reducers get something like file-a or file-b?

file-a:

k1 v1
k1 v2
k1 v3
k2 v1
k2 v2
k2 v3
k3 v1
k3 v2
k3 v3

file-b:

k1 v1
k1 v2
k2 v3
k3 v1
k2 v1
k1 v3
k3 v2
k2 v2
k3 v3

Andreas