Application Administration

An application uses a compound index on `{ 'status': 1, 'priority': -1 }`. Which query will efficiently use this index?

Refer to the exhibit. What is the primary cause of the performance issue seen in this query plan?

Refer to the exhibit. An aggregation pipeline is failing with an error. How can you modify the pipeline to allow it to process the large dataset?

Which connection string parameter should be used to ensure an application driver automatically discovers all members of a replica set?

What is the primary function of the 'wtimeout' setting in write concern?

Which mechanism ensures an application receives an error if a write is not persisted to the majority of nodes in a replica set?

A development team is building a Node.js application that connects to a MongoDB replica set. They want the driver to automatically retry certain write operations once if they fail due to a transient network error, without requiring custom retry logic in their code. Which connection string option should they enable?

A database administrator wants to configure a read preference that directs all read operations to the primary node of a replica set, ensuring the most up-to-date data. Which read preference mode should be used?

An application needs to perform a series of reads and writes across multiple documents in two collections atomically. The deployment is a replica set running MongoDB 4.2. Which feature should the application use?

A financial application requires that read operations never return data that could later be rolled back, even if it means reading from a secondary. The application connects to a replica set with readPreference=secondary. Which read concern level should be used to guarantee that the data read has been acknowledged by a majority of replica set members and cannot be rolled back?

An application is using a capped collection for logging. What happens when the collection reaches its configured size limit?

An application needs to update a user's balance. Which method ensures the operation is atomic for a single document?

An application uses a MongoDB driver that supports retryable writes. A write operation is sent to the primary, which applies the write but crashes before sending the acknowledgment. The driver receives a network error. What will the driver do by default?

Which MongoDB feature allows an application to receive real-time updates when data changes in a collection?

A MongoDB application requires that reads never see data that could be rolled back, even in the event of a replica set failover. The application also needs to read from secondary nodes to distribute load. Which read concern should be used with a secondary read preference?

An application uses a time-series collection. What is the benefit of using the TTL (Time-To-Live) index feature?

A developer is using the MongoDB Node.js driver and wants to ensure that a write operation is acknowledged by a majority of replica set members and is also written to the on-disk journal before returning success. Which write concern should be specified?

A MongoDB DBA is configuring a new application to connect to a sharded cluster. The application requires that reads are distributed across shards and that the driver automatically routes queries to the appropriate shard based on the shard key. Which component must be included in the connection string to enable this routing?

An application is performing many updates to a document. Which strategy is most effective to avoid fragmentation in the data files?

A database administrator is configuring a MongoDB replica set. The application requires that writes are acknowledged by a majority of voting members before being considered successful, and that the write is also written to the on-disk journal before acknowledgment. Which write concern specification achieves this?

A financial application must ensure that once a transaction is committed, the data will never be rolled back, even if the primary node crashes immediately after the write is acknowledged. Which write concern should be used?

Which TWO of the following are essential for maintaining performance in a sharded cluster?

When designing an application, what is the best practice for handling connection pools?

Which connection string parameter should be used to ensure that an application only reads data from nodes that are considered current and consistent?

What is the purpose of the 'write concern' in MongoDB?

Which read concern provides the strongest consistency guarantee by ensuring the data returned has been acknowledged by a majority of the replica set?

Which read preference allows the application to read from the closest member of the replica set to minimize network latency?