MongoDB: Terrible MapReduce Performance

Question

I have a long history with relational databases, but I\'m new to MongoDB and MapReduce, so I\'m almost positive I must be doing something wrong. I\'ll jump right into the qu

Answer 1

excerpts from MongoDB Definitive Guide from O'Reilly:

The price of using MapReduce is speed: group is not particularly speedy, but MapReduce is slower and is not supposed to be used in “real time.” You run MapReduce as a background job, it creates a collection of results, and then you can query that collection in real time.

options for map/reduce:

"keeptemp" : boolean 
If the temporary result collection should be saved when the connection is closed. 

"output" : string 
Name for the output collection. Setting this option implies keeptemp : true.