- 
    Type:Improvement 
- 
    Resolution: Fixed
- 
    Priority:Major - P3 
- 
    Affects Version/s: None
- 
    Component/s: Aggregation Framework
- 
    None
- 
        Query
- 
        Fully Compatible
- 
        None
- 
        None
- 
        None
- 
        None
- 
        None
- 
        None
- 
        None
It should be possible to perform reads from a secondary node and send the writes to the primary. If the read part of a pipeline is expensive but the write is not so expensive, this could help decrease load on the primary.
- is depended on by
- 
                    DRIVERS-868 Support running $out or $merge from a secondary with writes to the primary -         
- Closed
 
-         
- is related to
- 
                    SERVER-8853 MapReduce jobs execute exclusively on primaries -         
- Closed
 
-         
- 
                    SERVER-18992 DBClientRS should check aggregation pipelines for $out before sending the command to secondaries -         
- Closed
 
-