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PCDE Practice Question: Design innovative, scalable, and highly available cloud database solutions
A gaming company uses Cloud Bigtable to store player session data. The row key is player_id (UUID) and they have a column family 'sessions' with multiple columns per session. They want to query all sessions for a specific player in a given time range efficiently. Which row key design improvement should they consider?
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
✓
Append a reverse timestamp to the row key
Including a timestamp in the row key after the player_id allows scanning rows with a prefix of player_id and then filtering or scanning within a time range. Using a reverse timestamp helps get recent data first.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Add a hash prefix to player_id
Why it's wrong here
Already a UUID, adding hash is redundant and doesn't help time-range queries.
- ✓
Append a reverse timestamp to the row key
Why this is correct
This allows efficient scanning of recent sessions by scanning rows with player_id prefix and then reading sequentially.
- ✗
Create a secondary index on timestamp
Why it's wrong here
Bigtable does not have secondary indexes; row key design is the primary mechanism.
- ✗
Use a separate table for time-range queries
Why it's wrong here
Not necessary; row key design can handle it.
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Written by Johnson Ajibi, MSc IT Security
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.