Adaface Sample MongoDB Questions

Consider the following indexes on "musk" collection and the written queries. Select the queries that will use an index:

A) db.musk.find( { title : "SpaceX" } )
            B) db.musk.find( { _id : 22, date: ISODate("2020-01-01" } ) 
            C) db.musk.find( { date: ISODate("2020-01-01"), biz : "ElonSpaceX" } )
            D) db.musk.find( { contact : "111-111-1111"), info : "000-000-0000" } )

Given the following movies document in MongoDB, What will be the output of the query:

Given the following sample document in Mongodb:
            
            { x: 5, y: 3, z: 2, w: 1 }

If the collection name is 'adaface' with a compound index { x: 1, y: 1, z: 1, w: 1}, which of the following queries will not use in-memory sorting?

Consider a MongoDB setup where you have a replica set consisting of three members: Primary, Secondary, and Arbiter. A client's read preference is set to 'secondaryPreferred' to improve read performance during heavy load periods. Now, consider the following pseudo code snippet for a MongoDB script designed to insert documents into a collection 'orders':

const orderDocument = {
                orderId: '001',
                customerName: 'John Doe',
                product: 'Laptop',
                status: 'shipped'
            };
            db.orders.insert(orderDocument);
            
            const readResult = db.orders.find({}).readPref('secondaryPreferred');
            console.log(readResult);

Given this setup, which of the following statements is correct about the read and write operations performed? Take into account concepts like replication lag, read preference, network partitioning, and failover scenarios.

A: Write to secondary in sync.
            B: Primary always reads first.
            C: Reads prefer secondary.
            D: Arbiters store data.
            E: Lag affects secondary read.
            F: Arbiter handles writes.

Read the following chunk and pick the correct statements that apply:

A: The shard key defined for "sessions" collection is {userId: 1, sessionId: 1}
            B: All documents in chunk "test.sessions-abc-yxz" are located in shard "sh-1"
            C: Documents with fields {"userId": 10, "sessionId": "AB01" } are located part of chunk "test.sessions-abc-yxz"