- A
Use VPC firewall rules to block new connections until the issue resolves.
Why wrong: Firewall rules block new connections but do not resolve existing idle-in-transaction connections or CPU issues.
- B
Kill all idle-in-transaction connections using pg_terminate_backend.
Why wrong: Killing all idle-in-transaction connections indiscriminately may disrupt legitimate long-running transactions.
- C
Set the cloudsql.enable_idle_in_transaction_session_timeout flag to true and configure idle_in_transaction_session_timeout.
This flag automatically terminates idle-in-transaction sessions after a specified timeout, reducing CPU usage without manual intervention.
- D
Set a statement_timeout at the session level for new connections.
Why wrong: Setting statement_timeout affects new connections only and does not terminate existing idle-in-transaction connections.
Quick Answer
The answer is to set the `cloudsql.enable_idle_in_transaction_session_timeout` flag to true and configure `idle_in_transaction_session_timeout`. This is correct because idle-in-transaction connections hold locks and consume memory even when not executing queries, directly contributing to high CPU load in Cloud SQL for PostgreSQL; the timeout automatically terminates these sessions after a defined period, freeing resources without killing active transactions. On the Google Professional Cloud Database Engineer exam, this scenario tests your knowledge of Cloud SQL’s built-in, non-disruptive resource management flags versus manual `pg_terminate_backend` commands, which risk disrupting legitimate work. A common trap is choosing to manually kill connections, but the flag approach is safer and exam-preferred. Remember the mnemonic: “Idle transactions drain CPU—let the flag do the killing for you.”
PCDE Monitor and optimize database performance Practice Question
This PCDE practice question tests your understanding of monitor and optimize database performance. 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 managing a Cloud SQL for PostgreSQL instance that is experiencing high CPU usage and slow query performance. You notice that the database has a high number of idle-in-transaction connections. Which immediate action should you take to reduce CPU load without disrupting active transactions?
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 the cloudsql.enable_idle_in_transaction_session_timeout flag to true and configure idle_in_transaction_session_timeout.
Option C is correct because setting the `cloudsql.enable_idle_in_transaction_session_timeout` flag to true and configuring `idle_in_transaction_session_timeout` allows Cloud SQL to automatically terminate idle-in-transaction connections after a specified timeout, reducing CPU load without manually killing connections or disrupting active transactions. This is a built-in, non-disruptive mechanism that targets only connections that are holding resources while idle, freeing up CPU and memory for active queries.
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 VPC firewall rules to block new connections until the issue resolves.
Why it's wrong here
Firewall rules block new connections but do not resolve existing idle-in-transaction connections or CPU issues.
- ✗
Kill all idle-in-transaction connections using pg_terminate_backend.
Why it's wrong here
Killing all idle-in-transaction connections indiscriminately may disrupt legitimate long-running transactions.
- ✓
Set the cloudsql.enable_idle_in_transaction_session_timeout flag to true and configure idle_in_transaction_session_timeout.
Why this is correct
This flag automatically terminates idle-in-transaction sessions after a specified timeout, reducing CPU usage without manual intervention.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Set a statement_timeout at the session level for new connections.
Why it's wrong here
Setting statement_timeout affects new connections only and does not terminate existing idle-in-transaction connections.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the distinction between `statement_timeout` (which limits query execution time) and `idle_in_transaction_session_timeout` (which limits idle time within a transaction), and candidates mistakenly choose the session-level timeout thinking it will handle idle transactions, but it only applies to individual statements, not the idle period between statements within a transaction.
Detailed technical explanation
How to think about this question
Under the hood, `idle_in_transaction_session_timeout` is a PostgreSQL parameter (introduced in PostgreSQL 9.6) that specifies the maximum allowed idle time within a transaction before the session is forcibly terminated. When enabled in Cloud SQL via the `cloudsql.enable_idle_in_transaction_session_timeout` flag, the database backend periodically checks for sessions that have been idle in a transaction beyond the timeout and sends a `SIGTERM` to those backends, releasing locks and memory. In real-world scenarios, this is critical for preventing connection pool exhaustion and runaway CPU usage from applications that open transactions and then pause (e.g., waiting for user input or external API calls) without committing or rolling back.
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 healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
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.
- →
Monitor and optimize database performance — study guide chapter
Learn the concepts, then practise the questions
- →
Monitor and optimize database performance practice questions
Targeted practice on this topic area only
- →
All PCDE questions
503 questions across all exam domains
- →
Google Professional Cloud Database Engineer study guide
Full concept coverage aligned to exam objectives
- →
PCDE practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related PCDE practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Plan and manage database infrastructure practice questions
Practise PCDE questions linked to Plan and manage database infrastructure.
Define data structures and implement SQL for Business Intelligence practice questions
Practise PCDE questions linked to Define data structures and implement SQL for Business Intelligence.
Design and implement database schemas practice questions
Practise PCDE questions linked to Design and implement database schemas.
Monitor and optimize database performance practice questions
Practise PCDE questions linked to Monitor and optimize database performance.
PCDE fundamentals practice questions
Practise PCDE questions linked to PCDE fundamentals.
PCDE scenario practice questions
Practise PCDE questions linked to PCDE scenario.
PCDE troubleshooting practice questions
Practise PCDE questions linked to PCDE troubleshooting.
Practice this exam
Start a free PCDE practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this PCDE question test?
Monitor and optimize database performance — This question tests Monitor and optimize database performance — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Set the cloudsql.enable_idle_in_transaction_session_timeout flag to true and configure idle_in_transaction_session_timeout. — Option C is correct because setting the `cloudsql.enable_idle_in_transaction_session_timeout` flag to true and configuring `idle_in_transaction_session_timeout` allows Cloud SQL to automatically terminate idle-in-transaction connections after a specified timeout, reducing CPU load without manually killing connections or disrupting active transactions. This is a built-in, non-disruptive mechanism that targets only connections that are holding resources while idle, freeing up CPU and memory for active queries.
What should I do if I get this PCDE 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 →
Keep practising
More PCDE practice questions
- A company stores sensor data in BigQuery. They have a table 'sensor_readings' with columns: sensor_id, reading_time, val…
- Which THREE are valid considerations when designing BigQuery tables for BI reporting?
- A team is migrating an on-premises PostgreSQL database to Cloud SQL for PostgreSQL. The existing schema uses a large num…
- A company is designing a Cloud Firestore schema for a social media application. Users can follow other users, and the ap…
- Match each Cloud SQL tier to its description.
- A financial services company uses Cloud Spanner for a global transaction processing system. They notice that certain rea…
Last reviewed: Jun 30, 2026
This PCDE 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 PCDE exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.