- A
Increase the maximum number of Cloud Run instances to 20 to handle more requests.
Why wrong: More instances increase the number of database connections, potentially exceeding the limit further.
- B
Upgrade the Cloud SQL instance to db-n1-standard-4 (15 GB memory) to handle more connections.
Why wrong: A larger machine provides more memory and CPU but does not automatically increase max_connections; also cost increases significantly.
- C
Increase the max_connections parameter on Cloud SQL to 500.
This directly addresses the connection limit issue with minimal cost and no code changes.
- D
Reduce the concurrency setting on Cloud Run from 80 to 40.
Why wrong: Reducing concurrency reduces throughput and may not fully solve the connection limit issue if the number of instances remains high.
Quick Answer
The answer is to increase the Cloud SQL max_connections parameter to 500. This directly resolves the intermittent 500 errors by ensuring the database can handle the combined connection load from Cloud Run’s 10 instances (100 connections), App Engine’s automatic scaling (5 connections per instance), and occasional batch jobs (10 connections), which together easily exceed the current 250 limit. On the Google Professional Cloud Architect exam, this scenario tests your understanding of database connection limits under concurrent serverless workloads—a common trap is to over-engineer a solution by scaling instances or upgrading hardware, when simply adjusting a configuration parameter is the cheapest and least complex fix. The key insight is that high CPU on Cloud SQL often signals connection exhaustion, not compute capacity. Memory tip: “250 is half of 500—don’t let your connections get cut short.”
Google PCA Ensure solution and operations reliability Practice Question
This PCA practice question tests your understanding of ensure solution and operations reliability. 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 company runs a multi-tier application on Google Cloud: a frontend on App Engine Standard, a backend on Cloud Run, and a Cloud SQL database. The application experiences intermittent 500 errors when users submit forms. The errors correlate with high CPU usage on the Cloud SQL instance (db-n1-standard-2, 7.5 GB memory). The Cloud Run service has a concurrency setting of 80 and a maximum of 10 instances. The App Engine service uses automatic scaling. The team has verified that the application code is not the issue. They suspect the database is hitting connection limits. Current max_connections on Cloud SQL is 250. The Cloud Run service uses a connection pool of 10 connections per instance. The App Engine service uses a connection pool of 5 connections per instance. They also have a few batch jobs that run occasionally, using up to 10 connections. The team wants to resolve the errors with minimal cost and complexity. Which course of action should they take?
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
Increase the max_connections parameter on Cloud SQL to 500.
The intermittent 500 errors are caused by the Cloud SQL instance hitting its max_connections limit of 250. With Cloud Run using 10 connections per instance and up to 10 instances (100 connections), App Engine using 5 connections per instance (unknown instance count but likely significant), and batch jobs using up to 10 connections, the total can easily exceed 250. Increasing max_connections to 500 directly addresses the connection limit without changing instance size or scaling behavior, which is the simplest and most cost-effective fix.
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.
- ✗
Increase the maximum number of Cloud Run instances to 20 to handle more requests.
Why it's wrong here
More instances increase the number of database connections, potentially exceeding the limit further.
- ✗
Upgrade the Cloud SQL instance to db-n1-standard-4 (15 GB memory) to handle more connections.
Why it's wrong here
A larger machine provides more memory and CPU but does not automatically increase max_connections; also cost increases significantly.
- ✓
Increase the max_connections parameter on Cloud SQL to 500.
Why this is correct
This directly addresses the connection limit issue with minimal cost and no code changes.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Reduce the concurrency setting on Cloud Run from 80 to 40.
Why it's wrong here
Reducing concurrency reduces throughput and may not fully solve the connection limit issue if the number of instances remains high.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that upgrading the instance tier (more memory/CPU) automatically increases connection limits, when in fact max_connections is a configurable parameter that can be increased independently without changing the instance size.
Detailed technical explanation
How to think about this question
Cloud SQL's max_connections default is calculated based on the instance's memory tier; for db-n1-standard-2 (7.5 GB), the default is 250. The connection pool sizes in Cloud Run and App Engine are per instance, so the total connections = (Cloud Run instances * 10) + (App Engine instances * 5) + batch jobs. With automatic scaling, App Engine can spin up many instances under load, easily exceeding 250. Increasing max_connections is a simple parameter change (via gcloud or console) that requires no downtime, unlike scaling or upgrading the instance.
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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this PCA question test?
Ensure solution and operations reliability — This question tests Ensure solution and operations reliability — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Increase the max_connections parameter on Cloud SQL to 500. — The intermittent 500 errors are caused by the Cloud SQL instance hitting its max_connections limit of 250. With Cloud Run using 10 connections per instance and up to 10 instances (100 connections), App Engine using 5 connections per instance (unknown instance count but likely significant), and batch jobs using up to 10 connections, the total can easily exceed 250. Increasing max_connections to 500 directly addresses the connection limit without changing instance size or scaling behavior, which is the simplest and most cost-effective fix.
What should I do if I get this PCA 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
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Last reviewed: Jun 30, 2026
This PCA 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 PCA exam.
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