The answer is to increase the memory allocated to the Cloud Function. This directly resolves the memory limit exceeded error by providing more RAM for processing larger Pub/Sub messages or handling concurrent Firestore writes during peak load, without altering the invocation rate or reducing throughput. On the Google Professional Cloud Architect exam, this scenario tests your understanding that Cloud Functions (2nd gen) scale horizontally by default, so a memory bottleneck—not a concurrency limit—is the root cause; the common trap is to overcomplicate the fix with batching or throttling, which would sacrifice throughput. Remember the memory tip: "RAM is the pipe, not the pump"—increasing memory expands the data capacity per invocation, while throughput stays driven by event triggers.
Google PCA Ensure solution and operations reliability Practice Question
This PCA practice question tests your understanding of ensure solution and operations reliability. 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.
An organization uses Cloud Functions (2nd gen) for event-driven processing. They notice that some functions fail with 'memory limit exceeded' errors during peak load. The function processes messages from Pub/Sub and writes to Firestore. What should they do to improve reliability without sacrificing throughput?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Increase the memory allocated to the Cloud Function.
The 'memory limit exceeded' error indicates that the function's allocated memory is insufficient for the workload during peak load. Increasing the memory allocation (Option B) directly resolves this by providing more RAM for processing larger messages or concurrent operations, without altering the invocation pattern or throughput. Cloud Functions (2nd gen) allow memory to be set up to 32 GiB, and this change does not reduce the number of events processed per second.
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 concurrent function instances.
Why it's wrong here
More instances do not increase memory per instance; the existing instances will still hit the limit.
✓
Increase the memory allocated to the Cloud Function.
Why this is correct
More memory allows the function to handle larger data per invocation without hitting the limit.
Related concept
Read the scenario before looking for a memorised answer.
✗
Enable Pub/Sub batching to reduce the number of function invocations.
Why it's wrong here
Batching reduces invocations but each invocation may still process a large message and exceed memory.
✗
Split the function into multiple smaller functions, each handling a subset of the data.
Why it's wrong here
Splitting functions increases complexity and may not solve the per-message memory issue if each message is large.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that scaling out (more instances) solves memory issues, but the trap here is that memory limits are per-instance, so only increasing the per-instance memory allocation directly resolves the error.
Detailed technical explanation
How to think about this question
Cloud Functions (2nd gen) run on Cloud Run infrastructure, where memory is allocated per container instance and includes overhead for the runtime and dependencies. The 'memory limit exceeded' error occurs when the function's heap or stack usage exceeds the configured limit, often due to large payloads or inefficient data handling (e.g., loading entire Firestore documents into memory). Increasing memory also increases CPU proportionally in some configurations, which can improve processing speed for memory-bound tasks.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this PCA question in full detail.
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 memory allocated to the Cloud Function. — The 'memory limit exceeded' error indicates that the function's allocated memory is insufficient for the workload during peak load. Increasing the memory allocation (Option B) directly resolves this by providing more RAM for processing larger messages or concurrent operations, without altering the invocation pattern or throughput. Cloud Functions (2nd gen) allow memory to be set up to 32 GiB, and this change does not reduce the number of events processed per second.
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.
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Question Discussion
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