Explanation:In general, map-reduce operations have two phases: a map stage that processes each document and emits one or more objects for each input document, and reduce phase that combines the output of the map operation. 3. Running data aggregation on the ________ instance simplifies application code and limits resource requirements.
A. document
B. mongod
C. mongos
D. All of the mentioned
Answer:A
Explanation:In general, map-reduce operations have two phases: a map stage that processes each document and emits one or more objects for each input document, and reduce phase that combines the output of the map operation. 3. Running data aggregation on the ________ instance simplifies application code and limits resource requirements.
A. document B. mongod C. mongos D. All of the mentioned
Explanation:Like queries, aggregation operations in MongoDB use collections of documents as an input and return results in the form of one or more documents. 4. Documents enter a multi-stage __________ that transforms the documents into an aggregated result.