Type: New Feature
Affects Version/s: 2.0.0-alpha
Fix Version/s: None
Some people on the mailing lists have requested having read access in reducers to counters that were set by mappers. I propose that we provide a new interface for doing this. The counter data in addition to being set periodically to the Application Master would be put into the intermediate output of the mapper for each reducer and be specially marked as such. When the reducers fetch that data they can combine it together and provide a read only interface to it.
This allows users to potentially optimize their code on the reducer side if they know some special metadata before hand.
|Field||Original Value||New Value|
|Summary||Allow for metrics to be exchanged between mapps and reduces||Allow for metrics to be exchanged between maps and reduces|
|Affects Version/s||2.0.0-alpha [ 12320354 ]|
|Affects Version/s||0.24.0 [ 12317654 ]|