Question 108 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 company is migrating from a relational database to Cloud Bigtable. They have a table with a 'user_id' and 'login_timestamp'. Queries often filter by user_id and time range. What should be the row key?
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
✓
hash(user_id) + timestamp
hashing the user_id prevents hotspots, and appending timestamp enables range scans. 'user_id' alone may cause hotspots if sequential.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
timestamp
Why it's wrong here
Timestamp first causes write hotspots.
- ✓
hash(user_id) + timestamp
Why this is correct
Hash distributes, timestamp enables range queries.
- ✗
user_id + timestamp
Why it's wrong here
If user_id is sequential, hotspots occur.
- ✗
user_id
Why it's wrong here
Sequential user_id causes hotspots.
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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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