- A
Set max_connections = 8 * vCPU_count.
Why wrong: This formula is not used in Cloud SQL. max_connections is based on memory, not vCPU.
- B
Set max_connections = RAM_MB / 16.
Correct. Cloud SQL derives max_connections from memory: RAM_MB / 16.
- C
Set max_connections = 10 * IOPS.
Why wrong: IOPS does not determine max_connections.
- D
Set max_connections = vCPU_count * 1000.
Why wrong: This is not a standard Cloud SQL formula.
Question 132 of 1,000
PCDOE Design and Plan Database Solutions Practice Question
This PCDOE practice question tests your understanding of design and plan database solutions. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 company is migrating an on-premises OLTP application to Cloud SQL. The current database runs on a server with 64 GB RAM and 16 vCPUs, and handles thousands of write-heavy transactions per second. The team wants to size the Cloud SQL instance appropriately. Which sizing approach is correct for estimating max_connections?
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
✓
Set max_connections = RAM_MB / 16.
Cloud SQL for MySQL and PostgreSQL uses the formula `max_connections = RAM_MB / 16` as a default heuristic to prevent memory exhaustion from connection overhead. Each connection consumes approximately 16 MB of RAM for buffers and state, so dividing total RAM by 16 provides a safe upper bound. This approach directly ties connection limits to available memory, which is critical for write-heavy OLTP workloads that may open many concurrent connections.
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.
- ✗
Set max_connections = 8 * vCPU_count.
Why it's wrong here
This formula is not used in Cloud SQL. max_connections is based on memory, not vCPU.
- ✓
Set max_connections = RAM_MB / 16.
Why this is correct
Correct. Cloud SQL derives max_connections from memory: RAM_MB / 16.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Set max_connections = 10 * IOPS.
Why it's wrong here
IOPS does not determine max_connections.
- ✗
Set max_connections = vCPU_count * 1000.
Why it's wrong here
This is not a standard Cloud SQL formula.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that vCPU count or IOPS should drive connection limits, but the correct approach for Cloud SQL is always memory-based because connection overhead is the primary constraint in multi-tenant managed databases.
Detailed technical explanation
How to think about this question
Under the hood, each database connection in Cloud SQL allocates a private memory region for session state, temporary tables, and sort buffers — typically around 16 MB per connection in MySQL. The `max_connections` parameter is a hard limit; exceeding it causes new connections to be rejected. In write-heavy OLTP scenarios, high connection counts can also lead to contention on internal locks (e.g., the `LOCK_thread_count` mutex in MySQL), so setting `max_connections` too high degrades performance even if RAM is sufficient. Cloud SQL automatically adjusts this value based on instance tier, but manual sizing should always start from the RAM-based formula.
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 PCDOE question test?
Design and Plan Database Solutions — This question tests Design and Plan Database Solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Set max_connections = RAM_MB / 16. — Cloud SQL for MySQL and PostgreSQL uses the formula `max_connections = RAM_MB / 16` as a default heuristic to prevent memory exhaustion from connection overhead. Each connection consumes approximately 16 MB of RAM for buffers and state, so dividing total RAM by 16 provides a safe upper bound. This approach directly ties connection limits to available memory, which is critical for write-heavy OLTP workloads that may open many concurrent connections.
What should I do if I get this PCDOE 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.
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Last reviewed: Jul 4, 2026
This PCDOE 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 PCDOE exam.
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