MCQ Collection
Big Data Analytics MCQs
Practice Big Data Analytics questions with answers and explanations.
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Correct Answer: C. Free resources exist but are divided in a way that cannot satisfy pending container requests
Explanation:
For example, nodes may have spare memory but insufficient CPU for a requested container.
Better sizing and scheduling can improve packing.
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Correct Answer: C. The compiler determines a value's type from its expression
Explanation:
Scala is statically typed even when annotations are omitted.
The compiler infers types where sufficient information exists.
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Correct Answer: C. A value that may be present or absent
Explanation:
Some(value) represents presence and None represents absence.
Option reduces direct reliance on null.
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Correct Answer: C. A function that captures variables from its surrounding scope
Explanation:
The function carries references to external values it uses.
Spark must serialize captured values when sending closures to executors.
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Correct Answer: D. They create many small tasks and excessive scheduling overhead
Explanation:
Task startup cost can dominate actual processing for tiny inputs.
Container files or combined input formats can improve efficiency.
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Correct Answer: D. Placing a container near the input data when possible
Explanation:
Local or rack-local execution reduces network traffic.
The scheduler may balance locality against waiting time.
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Correct Answer: D. The absence of a meaningful return value
Explanation:
Unit is similar to void in other languages.
Its sole value is written as ().
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Correct Answer: D. An Option containing the value x
Explanation:
Some wraps an existing value in the Option type.
Code can safely distinguish it from None.
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Correct Answer: D. The object may be serialized and sent to every executor task
Explanation:
Unnecessary closure capture increases network and memory overhead.
Extracting only required fields produces smaller serialized functions.
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Correct Answer: A. It groups multiple small files into larger logical input splits
Explanation:
Fewer, larger splits reduce mapper count and scheduling overhead.
The underlying small files remain separate.
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Correct Answer: A. A task runs on a node containing its required HDFS block
Explanation:
Node locality provides the lowest network cost for reading HDFS input.
It is preferred when resources are available.
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Correct Answer: A. Code that evaluates to a value
Explanation:
Most Scala constructs, including if blocks, are expressions.
This supports concise functional composition.
