Explanation:It includes reads from the input collection, executions of the map function, executions of the reduce function, writes to a temporary collection during processing, and writes to the output collection. 3. If the ______ field for mapReduce has the sharded value, MongoDB shards the output collection using the _id field as the shard key.
A. input
B. $in
C. $out
D. None of the mentioned
Answer:A
Explanation:It includes reads from the input collection, executions of the map function, executions of the reduce function, writes to a temporary collection during processing, and writes to the output collection. 3. If the ______ field for mapReduce has the sharded value, MongoDB shards the output collection using the _id field as the shard key.
A. input B. $in C. $out D. None of the mentioned
Explanation:During the post-processing, each shard will pull the results for its own chunks from the other shards, run the final reduce/finalize, and write locally to the output collection. 4. In MongoDB ______ ,mongos retrieves the results from each shard, performs a merge sort to order the results