DATABRICKS-CERTIFIED-ASSOCIATE-DEVELOPER-FOR-APACHE-SPARK · Question #104
Which of the following best describes the similarities and differences between the MEMORY_ONLY storage level and the MEMORY_AND_DISK storage level?
The correct answer is D. The MEMORY_ONLY storage level will store as much data as possible in memory and will. MEMORY_ONLY stores RDD partitions as deserialized Java/JVM objects in heap memory. If not all partitions fit in memory, the ones that don't fit are simply dropped and will be recomputed from scratch when needed - they are never persisted anywhere. MEMORY_AND_DISK also stores…
Question
Which of the following best describes the similarities and differences between the MEMORY_ONLY storage level and the MEMORY_AND_DISK storage level?
Options
- AThe MEMORY_ONLY storage level will store as much data as possible in memory and will store
- BThe MEMORY_ONLY storage level will store as much data as possible in memory on two cluster
- CThe MEMORY_ONLY storage level will store as much data as possible in memory on two cluster
- DThe MEMORY_ONLY storage level will store as much data as possible in memory and will
- EThe MEMORY_ONLY storage level will store as much data as possible in memory and will
How the community answered
(50 responses)- A2% (1)
- B6% (3)
- D90% (45)
- E2% (1)
Explanation
MEMORY_ONLY stores RDD partitions as deserialized Java/JVM objects in heap memory. If not all partitions fit in memory, the ones that don't fit are simply dropped and will be recomputed from scratch when needed - they are never persisted anywhere. MEMORY_AND_DISK also stores data in memory first, but partitions that do not fit in memory are serialized and written to disk instead of being discarded. This is the critical difference: MEMORY_ONLY recomputes overflow partitions; MEMORY_AND_DISK spills overflow partitions to disk. Answer D correctly captures this distinction.
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