- A
Use Cloud Spanner change streams to sync data to Cloud SQL
Why wrong: This provides eventual consistency, not strong consistency.
- B
Eventual consistency with conflict resolution
Why wrong: Eventual consistency may not meet the strong consistency requirement.
- C
Migrate all data to Cloud Spanner to avoid cross-database transactions
Why wrong: While possible, the question asks for a pattern to use with existing heterogeneous databases.
- D
Saga pattern with orchestration and compensating transactions
Saga pattern coordinates distributed transactions and provides consistency via compensations.
Question 200 of 980
PCD Practice Question: Manage a Solution that Can Span Multiple Database Systems
This PCD practice question tests your understanding of manage a solution that can span multiple database systems. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A financial services company is architecting a multi-database solution. They need strong consistency across Cloud Spanner and Cloud SQL for a critical transaction flow. However, two-phase commit (2PC) across heterogeneous databases is not supported. Which pattern should they adopt to maintain data integrity?
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
✓
Saga pattern with orchestration and compensating transactions
The Saga pattern with orchestration and compensating transactions is correct because it maintains data integrity across heterogeneous databases like Cloud Spanner and Cloud SQL without relying on distributed transactions (2PC). In this pattern, each local transaction commits independently, and if a subsequent transaction fails, a compensating transaction is executed to undo the previous committed changes, ensuring eventual consistency and business-level rollback.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use Cloud Spanner change streams to sync data to Cloud SQL
Why it's wrong here
This provides eventual consistency, not strong consistency.
- ✗
Eventual consistency with conflict resolution
Why it's wrong here
Eventual consistency may not meet the strong consistency requirement.
- ✗
Migrate all data to Cloud Spanner to avoid cross-database transactions
Why it's wrong here
While possible, the question asks for a pattern to use with existing heterogeneous databases.
- ✓
Saga pattern with orchestration and compensating transactions
Why this is correct
Saga pattern coordinates distributed transactions and provides consistency via compensations.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume change streams or eventual consistency can substitute for strong consistency, but Cisco tests the understanding that only a saga with compensating transactions can provide business-level atomicity across unsupported heterogeneous databases.
Detailed technical explanation
How to think about this question
The Saga pattern avoids the need for a global coordinator by breaking the transaction into a sequence of local transactions, each with a compensating action. Under the hood, the orchestration service (e.g., using Cloud Workflows or a custom service) tracks state and invokes compensating transactions in reverse order if any step fails. A real-world scenario is a payment transfer between a Cloud Spanner ledger and a Cloud SQL user balance, where a failure after debiting the ledger requires a compensating credit to restore consistency.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this PCD question test?
Manage a Solution that Can Span Multiple Database Systems — This question tests Manage a Solution that Can Span Multiple Database Systems — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Saga pattern with orchestration and compensating transactions — The Saga pattern with orchestration and compensating transactions is correct because it maintains data integrity across heterogeneous databases like Cloud Spanner and Cloud SQL without relying on distributed transactions (2PC). In this pattern, each local transaction commits independently, and if a subsequent transaction fails, a compensating transaction is executed to undo the previous committed changes, ensuring eventual consistency and business-level rollback.
What should I do if I get this PCD question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jul 4, 2026
This PCD 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 PCD exam.
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