A transit desk uses Spark and Kafka to refresh arrival estimates every few seconds, then riders query those estimates through a fast document store. What role is NoSQL playing?
Select an answer to reveal the explanation.
Short Explanation
Streaming cooks the fresh arrival estimates; NoSQL is the counter where riders look them up. The document store serves what Spark and Kafka keep updating—it does not turn into Kafka or the JobTracker. You still need that serving layer for snappy queries.
Full Explanation
In Big Data ecosystems, NoSQL often acts as a low-latency serving store for results that streaming engines update continuously. Kafka and Spark handle ingestion and computation; the document store answers rider queries. NoSQL does not replace Kafka brokers or Hadoop JobTrackers, and streaming pipelines commonly still need a queryable serving tier.