Welcome to the club. The good news is that if you give the output collector a null key, it will just output the data in the value argument and ignore the key entirely.
Occasionally, the distinction is useful to avoid constructing yet another temporary data structure to hold a tuple. Word counting is the canonical example for this where outputting the word and the count naturally fits the API of the collector. You are right, however, that the key doesn't serve any key-like function when it comes out of the reduce. On 2/12/08 12:21 PM, "Yuri Pradkin" <[EMAIL PROTECTED]> wrote: > I don't understand why the key/value assumption is preserved AFTER the > reduce operation, in other words why the output of a reducer is > expected as <key,value> instead of arbitrary, possibly binary bytes?
