Design innovative, scalable, and highly available cloud database solutions →mediumMultiple ChoiceObjective-mapped
PCDE Practice Question: Design innovative, scalable, and highly available cloud database solutions
A startup is building a real-time analytics dashboard that ingests 500,000 events per second and needs to query the last hour of data with sub-second latency. The data has a high write volume and the query pattern is time-range scans. Which Google Cloud database is most appropriate?
⚠ Common exam trap
It's easy for candidates to choose BigQuery for analytics workloads, but BigQuery is not designed for sub-second real-time queries on streaming data, whereas Cloud Bigtable is purpose-built for high-throughput, low-latency time-series access.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Cloud Bigtable
Cloud Bigtable is the correct choice because it is a fully managed, scalable NoSQL database designed for high-throughput writes and low-latency time-series data access. It supports sub-second latency on time-range scans by storing data in sorted order by row key, making it ideal for ingesting 500,000 events per second and querying the last hour of data.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Cloud Spanner
Why it's wrong here
Cloud Spanner offers strong transactional consistency and horizontal scalability across regions, but its write throughput is limited by per-node commit timestamps and lock contention, making it unsuitable for 500,000 events per second with sub-second time-range scans. It is tempting because it excels at globally distributed, strongly consistent OLTP workloads—such as a multi-region financial ledger—where ACID transactions across shards are required, not high-velocity time-series analytics.
- ✗
Cloud SQL (PostgreSQL)
Why it's wrong here
Cloud SQL cannot scale to 500K writes per second; it is not designed for such high throughput.
- ✗
BigQuery
Why it's wrong here
BigQuery is for analytics on large datasets with latency in seconds, not real-time sub-second queries.
- ✓
Cloud Bigtable
Why this is correct
Bigtable supports millions of writes per second and sub-second latency for time-range scans, perfect for this workload.
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Senior Network & Security Engineer · founder of Courseiva
This PCDE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCDE exam.