Given the below statement, please choose the most probable reason:- "You have a web application with mongodb as a backend. A query returns a resultset, however when called a second time the result set is empty."

Choose the type of query where indexes can result in slower query response time.

For the query below db.collection.find( { x: 5 } ).sort( { z: 1} ) Choose the best index to support the query

how indexing improve query response time

Which method will shut down replica set?

How many members a replica set can have?

What is the maximum number of Indexes per collection allowed?

Best statement that describes: 'why aggregation queries outperform mapreduce for small datasets'.

Which expression can not be used with aggregation?

What will be the output of two command in MongoDB: db.mycol.insert({'_id':1}) db.mycol.insert({'_id':1})

Choose the best description of the output for the query below var weekAgo = Date.now() - (1000*60*60*24*7); db.visits_calc.group( { key:{date:true}, cond:{date:{$gt:weekAgo}}, reduce:function(obj, out) {out.day += obj.total}, initial:{day:0} });