Cloud Digital Leader Google Cloud Products and Services Practice Question
A company wants to migrate its on-premises Oracle database to Google Cloud. They need PostgreSQL compatibility with high performance for transaction processing and built-in support for AI-driven optimisations. Which database service should they choose?
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
✓
AlloyDB
AlloyDB is a PostgreSQL-compatible database with 4x faster transaction processing than standard PostgreSQL and AI-powered features for performance optimization.
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 is a horizontally scalable relational database service, but it is not PostgreSQL-compatible. It uses its own SQL dialect (GoogleSQL or Spanner SQL) and does not support PostgreSQL-specific features such as PL/pgSQL stored procedures, native data types, or the PostgreSQL wire protocol. While it handles distributed transactions and strong consistency, migrating an Oracle database to Spanner would require extensive SQL rewriting and schema redesign, making it a poor fit for a PostgreSQL-compatibility requirement.
- ✗
Bigtable
Why it's wrong here
Bigtable is a fully managed NoSQL wide-column database designed for low-latency, high-throughput analytical and operational workloads. It does not support relational schemas, SQL queries, joins, or transactions across rows, all of which are essential when migrating from an Oracle relational database. Since Bigtable also lacks the PostgreSQL wire protocol and compatibility layer, it is fundamentally unsuitable for a migration that demands PostgreSQL compatibility.
- ✗
Cloud SQL for PostgreSQL
Why it's wrong here
Cloud SQL for PostgreSQL is a managed, fully PostgreSQL-compatible service, but it does not include the AI-driven performance optimizations that the company expects for its Oracle migration. Cloud SQL relies on standard PostgreSQL storage and query execution, offering limited scalability and slower analytical performance compared to AlloyDB, which features a columnar engine and adaptive caching. For a workload that needs high performance and intelligent optimization, Cloud SQL is a valid but less capable alternative.
- ✓
AlloyDB
Why this is correct
AlloyDB is a fully managed, PostgreSQL-compatible database service engineered for high performance and scalability, with AI-driven optimizations such as adaptive caching and an integrated columnar engine. It provides up to 4x faster transactional performance and 10x faster analytical queries than standard PostgreSQL, and its compatibility layer supports Oracle-like data types, functions, and SQL syntax, easing migration from Oracle. These capabilities directly align with the company's requirement for a PostgreSQL-compatible database with intelligent performance enhancements.
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Key term
Google Cloud
Google Cloud is a suite of cloud computing services offered by Google that provides infrastructure, platform, and software solutions over the internet.
Key term
Service
A service is a software component or system that performs a specific function and is available to be used by other programs or users over a network.
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