What is the purpose of using the 'sparse' option when creating an index in MongoDB?
To compress the index data for reduced storage space.
To limit the index to only documents containing the indexed field.
To distribute the index data across multiple shards.
To create a case-insensitive index for text search.
Which component of MongoDB's architecture is responsible for managing data access and concurrency?
Query Engine
Router
Config Server
Storage Engine
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.
Avoiding the use of indexes within transactions as they can negatively impact performance.
Including as many operations as possible within a single transaction to simplify code logic.
Which write concern level ensures that a write operation is durable even if the primary node fails?
w: 1
w: all
w: majority
w: 0
Which of the following is NOT a built-in authentication mechanism in MongoDB?
API Key Authentication
LDAP
x.509 Certificate Authentication
SCRAM-SHA-1
Which stage of the explain plan indicates that an index was effectively used to limit the number of documents scanned?
FETCH
SHARD_MERGE
COLLSCAN
IXSCAN
What is the purpose of 'write concern' in MongoDB?
To control how many nodes must acknowledge a write operation.
To limit the number of writes per second.
To manage data compression for write operations.
To specify the level of security for write operations.
What is a key difference between single-document writes and multi-document transactions in MongoDB?
Multi-document transactions can only update a single document at a time.
Single-document writes offer ACID guarantees, while multi-document transactions do not.
Multi-document transactions provide atomicity across multiple documents, while single-document writes do not.
Single-document writes are only supported in sharded clusters, while multi-document transactions work in both standalone and sharded environments.
In WiredTiger, what data structure is used to store data on disk?
Skip List
Hash Table
Log-Structured Merge Tree
B-Tree
Which stage allows for conditional execution of pipeline stages in MongoDB's aggregation framework?
$ifNull
$cond
$switch
$case