Which stage of the explain plan indicates that an index was effectively used to limit the number of documents scanned?
COLLSCAN
FETCH
SHARD_MERGE
IXSCAN
The 'Attribute Pattern' in MongoDB schema design is most suitable for...
Representing historical data with frequent changes
Storing arrays of simple, non-repeating values
Modeling relationships between documents in different collections
Optimizing queries that require aggregation of data
Which component of MongoDB's architecture is responsible for managing data access and concurrency?
Router
Config Server
Storage Engine
Query Engine
What is a common reason for slow query performance despite having an index on the queried field?
The collection has a large number of documents
The indexed field has low cardinality (many documents share the same value)
The query uses a projection to select only a subset of fields
The index is too large to fit entirely in RAM
What is the role of SSL/TLS in securing MongoDB deployments?
Encrypting communication between MongoDB clients and servers
Encrypting data at rest within the database files
Providing a mechanism for user authentication
Auditing and logging database access
What is a shard key in MongoDB's sharding system?
A unique identifier assigned to each shard server
A password used to authenticate connections to the cluster
A field or set of fields used to distribute data across shards
An encryption key used for securing data on shards
Which operator within the $lookup stage specifies the field in the 'joined' collection that should match the 'localField'?
foreignField
as
from
localField
Which of the following is a recommended practice when using transactions in MongoDB?
Keeping transactions as long-running as possible to maximize the number of operations covered.
Keeping transactions short-lived and focused to minimize locking overhead and potential for conflicts.
Including as many operations as possible within a single transaction to simplify code logic.
Avoiding the use of indexes within transactions as they can negatively impact performance.
What does the 'Extended Reference' pattern in MongoDB schema design aim to achieve?
Creating a denormalized view of data for specific queries
Enforcing data integrity rules across multiple collections
Storing an entire referenced document within the main document
Combining embedding and referencing for optimal performance
In MongoDB, which data modeling concept allows for representing one-to-many relationships without joins?
Embedded documents
Data duplication
Junction tables
Foreign keys