PDE Storing the Data Practice Question
A company is migrating an on-premises PostgreSQL database to Google Cloud. They need a fully managed database that is compatible with PostgreSQL and can handle both transactional and analytical workloads with high performance. Which two database services meet these requirements? (Choose TWO.)
⚠ Common exam trap
Google often tests the distinction between general-purpose managed databases (Cloud SQL) and specialized high-performance databases (AlloyDB), and the trap here is that candidates may think BigQuery or Spanner are PostgreSQL-compatible because they support SQL, but they do not support the PostgreSQL dialect or transactional workloads natively.
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 SQL for PostgreSQL
Cloud SQL for PostgreSQL (B) is correct because it is a fully managed service that runs the native PostgreSQL engine, so it is directly compatible with the on-premises PostgreSQL database and supports transactional (OLTP) workloads. AlloyDB (D) is also correct because it is a fully managed, PostgreSQL-compatible database engine that is specifically designed for high-performance transactional workloads while also accelerating analytical queries through its columnar engine, making it well suited to mixed transactional and analytical use. Cloud Spanner (A) is not the right fit here because, although it is fully managed and highly scalable, it is not PostgreSQL-compatible in the native sense and is aimed at globally distributed OLTP rather than this migration scenario. BigQuery (C) is a fully managed analytical data warehouse optimized for OLAP, not a PostgreSQL-compatible transactional database. Firestore (E) is a fully managed NoSQL document database and is neither PostgreSQL-compatible nor designed for the transactional/analytical mix described.
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
Spanner is not PostgreSQL-compatible; it uses GoogleSQL or PostgreSQL dialect but is a different engine.
- ✓
Cloud SQL for PostgreSQL
Why this is correct
Fully managed, PostgreSQL-compatible, supports OLTP and some analytical queries.
- ✗
BigQuery
Why it's wrong here
BigQuery is not PostgreSQL-compatible and is purely analytical.
- ✓
AlloyDB
Why this is correct
PostgreSQL-compatible, with columnar engine for fast analytics, designed for hybrid workloads.
- ✗
Firestore
Why it's wrong here
Firestore is a NoSQL document database, not PostgreSQL-compatible.
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Written by Johnson Ajibi, MSc IT Security
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This PDE 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 PDE exam.