Question 177 of 1,446
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 team is designing a Spanner schema for an online gaming leaderboard. The leaderboard stores player scores and requires high write throughput. Which primary key design is BEST to avoid write hotspots?
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
✓
Primary key: (HashOfPlayerId, Timestamp)
Monotonically increasing keys (like score or timestamp) cause hotspotting. Using a random prefix (e.g., hash of player ID) ensures writes are distributed across splits. Player ID alone might also cause hotspotting if many players write simultaneously.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Primary key: (HashOfPlayerId, Timestamp)
Why this is correct
Hash prefix distributes writes evenly. Timestamp as second part allows ordering.
- ✗
Primary key: (PlayerId, Timestamp)
Why it's wrong here
PlayerId alone may still cause hotspotting if many players are active simultaneously.
- ✗
Primary key: (Score, PlayerId)
Why it's wrong here
Score is monotonically increasing, causing writes to concentrate on a single split.
- ✗
Primary key: (Timestamp, PlayerId)
Why it's wrong here
Timestamp leads to hotspotting as all writes happen at increasing times.
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Last reviewed: Jul 4, 2026
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.
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