PDE Ensuring solution quality Practice Test 2 — 15 Questions

Question 1

A data platform uses Cloud Spanner for transactional data. They are experiencing high latency during write-heavy periods. To maintain solution quality, what configuration change is most effective?

Accepted Answer

Use interleaved tables to reduce the number of split operations.. Option A is correct because interleaved tables improve data locality, reducing the number of splits and distributed commits, thus reducing write latency. Option B (increasing nodes) can increase throughput but may increase latency due to more distributed transactions. Option C (online schema changes) does not directly affect write performance. Option D (manual splitting) is not recommended and may worsen performance.

Answer

Enable online schema changes.

Answer

Increase the number of nodes in the Cloud Spanner instance.

Answer

Manually split the table using ALTER TABLE statements.

Question 2

A company uses Cloud Functions to process events from Cloud Storage. They notice that occasionally functions are not triggered. What should they check first to ensure solution quality?

Accepted Answer

Verify that the Cloud Storage bucket has notifications configured for the correct event type.. Option C is correct because the first step is to verify the Cloud Storage bucket notification configuration, as a misconfigured trigger will cause missed events. Option A (function timeout) does not cause missing triggers. Option B (memory) is unrelated. Option D (logs) are helpful but after verifying trigger configuration.

Answer

Check the logs for function execution.

Answer

Increase the function memory allocation.

Answer

Increase the function timeout.

Question 3

A financial services company uses Dataflow pipelines with late data handling. They need to ensure that all late-arriving data is processed correctly but also want to control costs. What is the best configuration?

Accepted Answer

Use fixed windows with allowed lateness set to the maximum expected delay (e.g., 2 days) and a trivial watermark.. Option D is correct because using fixed windows with allowed lateness set to the maximum expected delay and a trivial watermark balances completeness and cost. Option A (global window with long allowed lateness) can cause high state cost. Option B (session windows) may merge late data incorrectly. Option C (sliding windows with short allowed lateness and side input) is complex and may miss data.

Answer

Use a global window with a very long allowed lateness (e.g., 7 days).

Answer

Use session windows with a gap duration of 1 hour and allowed lateness of 2 days.

Answer

Use sliding windows with a short allowed lateness (e.g., 10 minutes) and a side input containing historical data.

Question 4

A team is deploying a model on AI Platform Prediction. They want to monitor for data drift to maintain model quality. Which service should they use?

Accepted Answer

AI Platform Continuous Evaluation. Option B is correct because AI Platform Continuous Evaluation is designed to monitor model performance and detect data drift. Option A (Cloud Monitoring) is for infrastructure metrics. Option C (Cloud Audit Logs) is for API activity. Option D (Cloud DLP) is for data loss prevention.

Answer

Cloud DLP

Answer

Cloud Monitoring

Answer

Cloud Audit Logs

Question 5

A data engineer needs to monitor the performance of BigQuery queries to identify opportunities for optimization. Which TWO metrics should they focus on? (Choose two.)

Accepted Answer

Slot usage. Options A and E are correct: Slot usage indicates resource consumption, and data scanned per query directly correlates with cost and performance. Option B (number of tables joined) is not a direct metric. Option C (execution time) is important but can be affected by many factors. Option D (number of users) is irrelevant.

Answer

Query execution time

Answer

Number of tables joined

Answer

Number of users

Question 6

A company uses Cloud Build to deploy containerized applications. They want to ensure build and deployment quality. Which THREE steps should they include in their CI/CD pipeline? (Choose three.)

Accepted Answer

Scan container images for vulnerabilities using Container Analysis.. Options B, D, and E are correct: Container scanning catches vulnerabilities, canary deployments reduce risk, and pinning base image digests ensures reproducibility. Option A (unit tests after deployment) is too late. Option C (direct deployment to production) bypasses safety checks.

Answer

Run unit tests after deployment.

Answer

Deploy directly to production on every commit.

Question 7

A company wants to ensure high availability for their Cloud SQL instance. Which TWO actions are most appropriate? (Choose two.)

Accepted Answer

Create a read replica in a different region.. Options A and B are correct: A read replica in a different region provides disaster recovery, and automatic backups allow point-in-time recovery. Option C (failover replica in same region) provides HA but not DR. Option D (increased memory) does not improve availability. Option E (horizontal scaling with read replicas) does not provide failover for writes.

Answer

Configure a failover replica in the same region.

Answer

Increase the instance's memory and storage size.

Answer

Set up horizontal scaling with multiple read replicas.

Question 8

Refer to the exhibit. A team configured a Cloud Monitoring alerting policy as shown. They recently started receiving false positive alerts. What is the most likely cause?

Accepted Answer

The duration of 60 seconds is too short, making the alert sensitive to brief spikes.. Option C is correct because the duration is set to 60 seconds, meaning any 60-second window with a rate >10 will trigger an alert. If the error count is bursty, brief spikes cause false positives. Increasing the duration would smooth out transient spikes. Option A (alignment period) affects granularity but does not cause false positives. Option B (threshold) might be low, but the primary issue is the short duration. Option D (aligner) is appropriate for rate.

Answer

The alignment period of 60 seconds is too short, causing noise.

Answer

The threshold of 10 is too low.

Answer

The aggregator should be ALIGN_SUM instead of ALIGN_RATE.

Question 9

Refer to the exhibit. A team received this error when running a query. Which optimization should they apply first?

Accepted Answer

Add a WHERE clause on a partitioning column.. Option A is correct because adding a WHERE clause on a partitioning column (if the table is partitioned by date) would allow BigQuery to prune partitions, significantly reducing data scanned. Option B (clustering) is helpful but less effective than partitioning for date-range queries. Option C (batch job) does not reduce resource usage. Option D (reducing rows early) is a good practice but not as impactful as partition pruning.

Answer

Use clustering on the date column.

Answer

Reduce the number of rows by aggregating in a subquery.

Answer

Run the query as a batch job.

Question 10

Refer to the exhibit. A subscriber is unable to pull messages from the topic. What is the most likely cause?

Accepted Answer

No subscription has been created for the topic.. Option B is correct because a subscription must exist for pulling messages; the topic alone is not enough. Option A (publisher role) is not needed for subscribers. Option C (subscriber role on topic) is correct but the subscriber also needs to have a subscription. Option D (viewer role) is irrelevant.

Answer

The service account has the subscriber role but the topic is not configured correctly.

Answer

The service account needs roles/pubsub.viewer to list subscriptions.

Answer

The service account lacks roles/pubsub.publisher.

Question 11

A company uses Cloud Monitoring to track application latency. They notice a spike in latency every 30 minutes. What is the best initial step to diagnose the issue?

Accepted Answer

Check if scheduled jobs or cron tasks overlap.. Recurring spikes at regular intervals often indicate a scheduled process (e.g., cron job, batch job) that runs every 30 minutes. Checking for overlapping scheduled jobs is the most efficient first step before scaling or other actions.

Answer

Increase the number of instances to handle the load.

Answer

Enable Cloud Trace for all requests.

Answer

Change the alert threshold to ignore the spikes.

Question 12

A team deploys a new version of a Cloud Function. After deployment, error rates increase significantly. What is the most efficient way to diagnose the cause?

Accepted Answer

Check Cloud Logging for error stacks and exceptions.. Cloud Logging captures function execution logs and error stacks; reviewing them is the fastest way to understand the failure.

Answer

Deploy a debug version with additional logging.

Answer

Increase the function timeout and retry settings.

Answer

Immediately rollback to the previous version.

Question 13

A data pipeline using Dataflow processes streaming data. Late-arriving events are currently being dropped. How should the team modify the pipeline to ensure late data is processed correctly?

Accepted Answer

Configure triggers with allowed lateness and accumulation of late firings.. Dataflow allows setting allowed lateness on windows; trigger configuration can handle late data by emitting updates.

Answer

Use side inputs to join late data with the main stream.

Answer

Use streaming inserts into BigQuery and ignore late data.

Answer

Increase the window duration to cover late data.

Question 14

A company uses GKE to run microservices. They want to ensure the application restarts automatically if it becomes unresponsive. Which probes should they configure in their pod spec?

Accepted Answer

Both readiness and liveness probes.. Liveness probes determine when to restart a container; readiness probes determine when a pod is ready to serve traffic. Both are needed for full resilience.

Answer

Startup probes only.

Answer

Liveness probes only.

Answer

Readiness probes only.

Question 15

After migrating a production Cloud SQL for PostgreSQL database to a larger machine type, the team notices slower queries. What is the best step to identify the cause?

Accepted Answer

Enable pg_stat_statements and review query execution times.. Option C is correct because pg_stat_statements is a PostgreSQL extension that provides detailed query execution statistics, including total execution time, number of calls, and I/O metrics. After migrating to a larger machine type, slower queries often stem from plan changes due to different hardware characteristics or configuration settings; reviewing pg_stat_statements output helps pinpoint which queries are underperforming and why.

Answer

Reindex all tables to improve index efficiency.

Answer

Enable query caching through the database flags.

Answer

Increase max_connections to handle more concurrent queries.