PCDOE Optimizing service performance Practice Test 6 — 15 Questions

Question 1

A team is optimizing the performance of their application running on Cloud Run. They want to reduce cold starts. Which two actions would help? (Select TWO)

Accepted Answer

Enable min instances. Option A (Enable min instances) is correct because setting a minimum instance count keeps warm container instances running even when there is no traffic, so requests are served without the latency of spinning up a new container, directly reducing cold starts. Option D (Use a custom container base image with reduced size) is correct because a smaller image pulls and initializes faster, shortening the time Cloud Run needs to start a new instance and thereby reducing cold-start duration. Option B (Increase the maximum number of container instances) only affects scaling ceiling under load and does not prevent cold starts for new instances. Option C (Increase the CPU limit) may speed up execution but does not eliminate the cold-start initialization delay and can even increase cost without addressing instance startup. Option E (Enable HTTP/2) improves transport efficiency for requests but has no effect on container startup or cold-start latency.

Answer

Increase the maximum number of container instances

Answer

Increase the CPU limit

Answer

Enable HTTP/2

Question 2

A company uses Cloud Monitoring to set up alerting for their production system. They want to reduce alert fatigue while ensuring critical issues are caught quickly. Which two strategies should they implement? (Select TWO)

Accepted Answer

Use notification channels with escalation policies. Option A is correct because Cloud Monitoring notification channels can be paired with escalation policies so that alerts are routed to the right on-call responder and only escalate to additional recipients (e.g., via SMS or phone) when the issue is not acknowledged within a defined time, reducing noise while ensuring critical issues reach someone quickly. Option C is correct because alert aggregation and deduplication group related incidents (for example, multiple time series from the same service or incident) into a single notification, preventing duplicate pages and lowering alert fatigue without suppressing genuine critical signals. Option B is wrong because setting low thresholds makes alerts fire more often on minor or transient deviations, which increases false positives and worsens alert fatigue. Option D is wrong because disabling alerts during off-hours can cause critical production issues to go undetected, contradicting the goal of catching critical issues quickly. Option E is wrong because creating separate alerts for every microservice multiplies notification volume and fragments incident context, which increases rather than reduces alert fatigue.

Answer

Use low threshold values to catch issues early

Answer

Disable alerts during off-hours

Answer

Set up separate alerts for each microservice

Question 3

A DevOps team is investigating performance issues in their GKE cluster. They want to use Cloud Profiler to identify the bottleneck. Which three steps are required to start profiling? (Select THREE)

Accepted Answer

Configure IAM permissions. Option A is correct because the identity running the workload (the GKE node's service account or Workload Identity principal) must have the Cloud Profiler Agent role (roles/cloudprofiler.agent) or equivalent cloudprofiler.profiles.create permission to write profile data. Option B is correct because Cloud Profiler requires the profiling agent library to be linked into the application container — for Go, Java, Node.js, and Python it is added as a dependency, and for other languages a specific agent binary must be deployed — so the agent must be present in the workload. Option C is correct because the Cloud Profiler API (cloudprofiler.googleapis.com) must be enabled in the project before profiles can be ingested and viewed. Option D is not required: Cloud Profiler does not rely on a sidecar proxy; the agent runs in-process and sends profiles directly to the Cloud Profiler backend. Option E is not required: no custom profiling endpoints need to be added to the application code; the agent libraries collect and export profiles automatically once initialized.

Answer

Install a sidecar proxy

Answer

Modify the application code to include profiling endpoints

Question 4

A company notices increased latency for their web application running on Compute Engine. They suspect a database bottleneck. Which Google Cloud service should they use to identify slow queries?

Accepted Answer

Cloud SQL Query Insights. Cloud SQL Query Insights is the correct choice because it is a Google Cloud managed service specifically designed to identify and analyze database performance issues, including slow queries, in Cloud SQL instances. It provides detailed query performance metrics, execution plans, and recommendations to optimize database queries, directly addressing the bottleneck in a Compute Engine web application.

Answer

Cloud Logging

Answer

Cloud Debugger

Answer

Cloud Trace

Question 5

A company's Cloud SQL for PostgreSQL instance is experiencing performance degradation. They observe a high number of idle connections and slow transaction commit times. Which combination of actions will most effectively address this issue?

Accepted Answer

Configure statement timeout and use PgBouncer for connection pooling.. The high number of idle connections and slow transaction commit times indicate connection management and resource contention issues. PgBouncer reduces overhead by pooling and reusing database connections, while statement timeout prevents long-running queries from holding locks and consuming resources, directly addressing both symptoms.

Answer

Add a read replica and route read-only queries to it.

Answer

Increase the storage size and enable automatic backup.

Answer

Drop unused indexes and run VACUUM.

Question 6

A web application serves static assets (images, CSS, JavaScript) from Compute Engine instances. Users in different geographic regions report slow page loads. Which Google Cloud service can be used to improve performance for these users?

Accepted Answer

Cloud CDN. Cloud CDN (Content Delivery Network) caches static assets at Google's globally distributed edge points of presence (PoPs). When users request images, CSS, or JavaScript, the content is served from the nearest edge cache rather than the origin Compute Engine instances, reducing latency and improving page load times for geographically distributed users.

Answer

VPC Network Peering

Answer

Cloud Load Balancing

Answer

Cloud NAT

Question 7

A company is migrating a batch processing workload to Google Cloud. The workload is CPU-intensive and runs for a few hours each day. Which Compute Engine machine family should they choose to optimize performance and cost?

Accepted Answer

Compute-optimized (C2/C2D). A is correct because the workload is CPU-intensive and runs for a few hours each day, which is a sustained, compute-bound task. Compute-optimized machines (C2/C2D) are designed specifically for high-performance computing (HPC) and batch processing, offering the highest ratio of vCPU to memory and the fastest single-threaded performance on Google Cloud. This minimizes runtime and cost per job compared to general-purpose or burstable families.

Answer

Burstable (T2D)

Answer

GPU-accelerated (A2)

Answer

Memory-optimized (M2)

Question 8

A Cloud Run service experiences high latency during cold starts. The service is memory-intensive. Which configuration change will most effectively reduce cold start latency?

Accepted Answer

Set a minimum number of instances.. Setting a minimum number of instances ensures that a baseline of pre-warmed instances is always running, eliminating cold starts for the initial requests. For a memory-intensive service, this avoids the latency penalty of loading large libraries or datasets into memory on first invocation. This is the most direct and effective configuration change to reduce cold start latency.

Answer

Decrease the container concurrency setting.

Answer

Increase the max instances limit.

Answer

Enable CPU boost for the service.

Question 9

A DevOps team wants to serve static content from a Cloud Storage bucket with low latency globally. They also need TLS termination. Which load balancer type should they use?

Accepted Answer

External HTTP(S) Load Balancer. External HTTP(S) Load Balancer is the correct choice because it provides global anycast IP addresses, TLS termination at the Google Front End (GFE), and integrates directly with Cloud Storage buckets as a backend. This enables low-latency content delivery worldwide while offloading SSL decryption to the load balancer.

Answer

External Network Load Balancer

Answer

SSL Proxy Load Balancer

Answer

Internal HTTP(S) Load Balancer

Question 10

A company is transferring large datasets from on-premises to Google Cloud using a VPN. They notice high latency due to packet loss. What is the most effective way to improve throughput?

Accepted Answer

Set up Dedicated Interconnect for a more reliable connection.. Dedicated Interconnect provides a direct, private physical connection between on-premises and Google Cloud, bypassing the public internet entirely. This eliminates the packet loss and high latency inherent in VPN tunnels over the internet, offering consistent throughput and lower latency for large dataset transfers.

Answer

Enable compression on the VPN tunnel.

Answer

Increase the number of VPN tunnels and use BGP multipath.

Answer

Use a multi-region GCP endpoint and distribute traffic.

Question 11

Which TWO practices should be implemented to optimize query performance in Cloud Spanner?

Accepted Answer

Use interleaved tables to co-locate related rows.. Option C is correct because interleaved tables physically co-locate child rows with their parent rows in the same split, so parent-child joins and lookups can be executed without network hops or distributed joins, which directly reduces query latency and improves performance. Option E is correct because Cloud Spanner uses secondary indexes to satisfy predicates efficiently; defining secondary indexes on columns frequently referenced in WHERE clauses lets the optimizer perform index scans instead of full table scans, cutting the amount of data read. Option A is not appropriate because manually splitting large tables into many smaller tables breaks the relational model and does not address Spanner's automatic sharding, which already distributes data across splits. Option B is wrong because creating excessive indexes on all columns adds write amplification and storage overhead and can degrade write performance without benefiting queries. Option D is incorrect because interleaving is a parent-child locality mechanism within a database and cannot be applied globally across regions; cross-region distribution is handled by the instance configuration, not by interleaving.

Answer

Split large tables into multiple smaller tables to distribute load.

Answer

Create as many indexes as possible on all columns.

Answer

Use globally distributed interleaving across regions.

Question 12

Which THREE strategies can reduce API latency in Apigee?

Accepted Answer

Enable response compression in the API proxy.. Option B is correct because enabling response compression (e.g., gzip via the CompressResponse policy or the compression.* flow variables) shrinks the payload size sent to clients, reducing transfer time and thus perceived API latency. Option C is correct because connection pooling (configured through the TargetEndpoint HTTPTargetConnection properties such as keepalive and max connections, or the TargetServer configuration) reuses TCP/TLS connections to the backend, avoiding repeated handshake and connection-setup overhead on every request. Option D is correct because implementing caching (e.g., the ResponseCache or LookupCache/PopulateCache policies backed by Apigee's cache) serves frequently accessed responses directly from the cache instead of invoking the backend, dramatically cutting round-trip latency. Option A is not correct because disabling TLS termination does not reduce latency in a meaningful, recommended way and would compromise security; TLS termination is a standard, optimized function in Apigee. Option E is not correct because increasing analytics data collection frequency adds processing and messaging overhead and does not reduce request/response latency.

Answer

Disable TLS termination to reduce overhead.

Answer

Increase the analytics data collection frequency.

Question 13

Which TWO actions can reduce startup latency for a Cloud Run service?

Accepted Answer

Optimize the container image to reduce size.. Option C is correct because a smaller container image reduces the time Cloud Run needs to pull the image and start the container, directly lowering cold-start latency. Option E is correct because setting a minimum number of instances keeps at least one instance warm and ready, so requests avoid cold starts entirely. Option A is incorrect because deploying separate regional services affects availability and locality, not the startup time of a given instance. Option B is incorrect because the maximum instances limit only caps horizontal scaling and does not make individual instances start faster. Option D is incorrect because container concurrency controls how many requests a single instance handles simultaneously, which affects throughput and resource use rather than startup latency.

Answer

Use a regional Cloud Run with separate service per region.

Answer

Increase the maximum instances limit.

Answer

Increase the container concurrency setting.

Question 14

Refer to the exhibit. A DevOps engineer notices that instance-1 runs on older CPU platform. The application is sensitive to CPU features that are only available on Skylake or newer. Which action should be taken to optimize performance?

Accepted Answer

Stop instance-1 and update the minimum CPU platform to Skylake.. Stopping the instance and updating the minimum CPU platform to Skylake ensures that the instance is rescheduled onto a host that meets the required CPU feature set. This action directly addresses the application's sensitivity to CPU features available only on Skylake or newer, without requiring a full recreation or risking compatibility issues during live migration.

Answer

Live migrate instance-1 to a different host.

Answer

Use Terraform to add a lifecycle rule to ignore changes.

Answer

Terminate instance-1 and recreate it with a newer machine type.

Question 15

Refer to the exhibit. What does the alert condition indicate?

Accepted Answer

It alerts for any Cloud Run revision that has more than 1000 requests in a 1-minute window.. The alert condition in the exhibit uses a per-revision metric (e.g., `run.googleapis.com/request_count`) with a threshold of 1000 and a 1-minute window. This means the alert fires for any individual Cloud Run revision that exceeds 1000 requests within that window, not for the aggregate across all revisions. Option B correctly identifies this per-revision behavior.

Answer

It alerts when the request count drops below 1000 for 1 minute.

Answer

It alerts when the average request count across all revisions exceeds 1000 over 1 minute.

Answer

It alerts when the total request count across all revisions exceeds 1000 per minute.