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Ensuring successful operation of a cloud solution →hardMultiple ChoiceObjective-mapped

Quick Answer

The immediate fix is to terminate the long-running table scan queries, as this directly stops the CPU-intensive sequential scans and restores service, while the root cause fix is to add indexes on the frequently queried columns of the 500 GB unindexed table. This works because missing indexes force PostgreSQL to perform full table scans, which consume excessive CPU and lock resources, especially on large tables; killing those queries drops CPU utilization instantly, and adding indexes eliminates the need for future scans. On the Google Associate Cloud Engineer exam, this scenario tests your ability to prioritize immediate incident response over permanent solutions, with a common trap being to add indexes first (which takes too long during an outage) or to scale up the instance (which only masks the problem). Remember the memory tip: “Kill first, index later” — stop the bleeding before applying the bandage.

Google ACE Practice Question: Ensuring successful operation of a cloud solution

This ACE practice question tests your understanding of ensuring successful operation of a cloud solution. 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.

You are on-call and receive a PagerDuty alert: `Cloud SQL CPU utilization > 90% for 15 minutes`. Checking `pg_stat_activity`, you find 200 connections with many in `idle` state and 15 queries running for > 5 minutes each. The long queries are table scans on a 500 GB unindexed table. What should you do IMMEDIATELY to restore service, and what is the root cause fix?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

Clue: "immediately / without restart"
Why it matters: Time or reboot constraint — the correct answer must take effect right away without requiring a reboot or reload.

Question 1hardmultiple choice

Full question →

A
Restart the Cloud SQL instance to clear all connections and queries.
Why wrong: Restarting causes full database downtime (60–120 seconds) and doesn't fix the root cause. Terminating specific long-running queries is faster and less disruptive.
B
Terminate the long-running table scan queries immediately, then add indexes on the frequently queried columns as the root cause fix.
pg_terminate_backend(pid) kills the specific long-running queries to restore CPU. Adding indexes addresses the root cause: full table scans due to missing indexes.
C
Increase Cloud SQL's CPU to a larger machine type to handle the current load.
Why wrong: Scaling up may provide temporary relief but doesn't fix full table scans — they'll still be slow and consume disproportionate resources. Root cause is missing indexes.
D
Reduce `max_connections` to prevent new connections from adding load.
Why wrong: Reducing max_connections would block legitimate new connections without helping the running long queries. The problem is long-running queries, not connection count.

Full breakdown with real-world context →

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

✓

Terminate the long-running table scan queries immediately, then add indexes on the frequently queried columns as the root cause fix.

Option B is correct because terminating the long-running table scans immediately stops the CPU-intensive queries, restoring service. The root cause is the missing index on the 500 GB table, which forces sequential scans and high CPU usage. Adding indexes on frequently queried columns eliminates the need for full table scans, preventing recurrence.

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.

✗
Restart the Cloud SQL instance to clear all connections and queries.
Why it's wrong here
Restarting causes full database downtime (60–120 seconds) and doesn't fix the root cause. Terminating specific long-running queries is faster and less disruptive.
✓
Terminate the long-running table scan queries immediately, then add indexes on the frequently queried columns as the root cause fix.
Why this is correct
pg_terminate_backend(pid) kills the specific long-running queries to restore CPU. Adding indexes addresses the root cause: full table scans due to missing indexes.
Clue confirmation
The clue word "immediately / without restart" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Increase Cloud SQL's CPU to a larger machine type to handle the current load.
Why it's wrong here
Scaling up may provide temporary relief but doesn't fix full table scans — they'll still be slow and consume disproportionate resources. Root cause is missing indexes.
✗
Reduce `max_connections` to prevent new connections from adding load.
Why it's wrong here
Reducing max_connections would block legitimate new connections without helping the running long queries. The problem is long-running queries, not connection count.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Google Cloud often tests the distinction between immediate mitigation (terminating bad queries) and root cause fix (adding indexes), tempting candidates to choose a scaling or restart option that avoids addressing the fundamental indexing problem.

Detailed technical explanation

How to think about this question

In PostgreSQL (Cloud SQL), `pg_stat_activity` shows queries in `active` state with `wait_event` indicating CPU or I/O wait. Long-running table scans on a 500 GB table cause high CPU due to sequential page reads and tuple processing. Terminating queries with `pg_cancel_backend()` or `pg_terminate_backend()` sends a SIGINT or SIGTERM, rolling back the transaction. The root fix is creating a B-tree index on the WHERE clause columns, which reduces query cost from sequential scan to index scan, drastically lowering CPU and I/O.

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 ACE question test?

Ensuring successful operation of a cloud solution — This question tests Ensuring successful operation of a cloud solution — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Terminate the long-running table scan queries immediately, then add indexes on the frequently queried columns as the root cause fix. — Option B is correct because terminating the long-running table scans immediately stops the CPU-intensive queries, restoring service. The root cause is the missing index on the 500 GB table, which forces sequential scans and high CPU usage. Adding indexes on frequently queried columns eliminates the need for full table scans, preventing recurrence.

What should I do if I get this ACE question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

Are there clue words in this question I should notice?

Yes — watch for: "immediately / without restart". Time or reboot constraint — the correct answer must take effect right away without requiring a reboot or reload.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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