Implement output option for aggregation pipelines only to unsharded collections. Input collections can be sharded.
This should be considered a part of SERVER-3253. SERVER-3253 dealt with commits that only dealt with unsharded clusters.
sharded map-reduce output should be parallelized and properly distribute chunks
support cursor based aggregation
$tee command for aggregation framework
Aggregate Command will support $out
Support $out aggregation pipeline operator
new aggregation framework