Explanation:For sharded collections these unique indexes cannot enforce uniqueness because insert and indexing operations are local to each shard. 3. ________ tests to see if the mongo shell is connected to a mongos instance.
A. sh._checkMongos()
B. sh.addShard()
C. sh._lastMigration()
D. All of the mentioned
Answer:A
Explanation:For sharded collections these unique indexes cannot enforce uniqueness because insert and indexing operations are local to each shard. 3. ________ tests to see if the mongo shell is connected to a mongos instance.
A. sh._checkMongos() B. sh.addShard() C. sh._lastMigration() D. All of the mentioned
Explanation:The sh._checkMongos() method throws an error message if the mongo shell is not connected to a mongos instance. 4. _______ reports on the active balancer lock, if it exists.