PCD Practice Test 12 — 15 Questions

Question 1

Which TWO are correct ways to reduce logging costs in Google Cloud? (Choose two.)

Accepted Answer

Set log bucket retention to a shorter period. Option A is correct because Cloud Logging charges for storage based on how long logs are retained in a log bucket; setting a shorter retention period (for example, reducing the default 30-day _Default bucket retention) means older entries are deleted sooner, directly lowering storage costs. Option E is correct because exclusion filters in Cloud Logging let you drop low-value, high-volume entries such as debug-level logs before they are ingested into a log bucket, reducing both ingestion and storage charges. Option B is wrong because disabling all audit logs removes security and compliance visibility and is not a legitimate cost-optimization technique; audit logs are also often required by policy. Option C is wrong because exporting all logs to BigQuery adds BigQuery storage and query costs rather than reducing logging costs. Option D is wrong because increasing retention from 30 to 365 days keeps log data far longer, increasing storage charges.

Answer

Disable all audit logs to reduce volume

Answer

Export all logs to BigQuery for analysis

Answer

Increase the retention period from 30 days to 365 days

Question 2

An e-commerce platform uses Cloud Spanner for its inventory system. They notice that the processing units utilization is consistently above 90% during peak hours, causing increased read latency. They want to automatically scale capacity based on load. What should they configure?

Accepted Answer

Enable auto-scaling by setting min and max processing units with a high-priority CPU target. Cloud Spanner supports automatic scaling by configuring a minimum and maximum number of processing units (or nodes) along with a high-priority CPU utilization target. This allows the instance to scale capacity automatically during peak hours, addressing the >90% utilization and read latency. Manual scaling or switching to nodes does not provide automatic load-based scaling.

Answer

Switch from processing units to nodes for better performance

Answer

Manually increase the number of nodes

Answer

Reduce the number of processing units to lower cost

Question 3

A developer is writing unit tests for a Cloud Function that reads from Firestore. They want to avoid real Firestore calls in tests. Which approach is best?

Accepted Answer

Mock the Firestore client library in the test code. Mocking the Firestore client library in unit tests is the best approach because it isolates the function's logic from external dependencies, allowing tests to run quickly and deterministically without any network calls. By replacing the Firestore client with a mock, developers can simulate various responses and error conditions, ensuring the unit test focuses solely on the function's code. This aligns with the principle of unit testing: test a single unit in isolation, not its integrations.

Answer

Use Cloud Functions local emulator with Firestore emulator

Answer

Create a test project with real Firestore and use real calls

Answer

Use Firestore emulator for tests

Question 4

Drag and drop the steps to troubleshoot a failed Cloud Build in the correct order.

Accepted Answer

Check Cloud Build logs first, then examine build configuration, then fix identified issues, then re-run the build.. Troubleshooting involves reviewing logs and configuration, then fixing and re-running.

Answer

Re-run the build first, then check logs, then examine configuration, then fix issues.

Answer

Examine build configuration first, then re-run the build, then check logs, then fix issues.

Answer

Fix issues first, then check logs, then examine configuration, then re-run.

Question 5

Drag and drop the steps to set up a Firestore database in native mode in the correct order.

Accepted Answer

Enable Firestore API, then Create Firestore database in native mode, then Add data to the database. Firestore native mode is selected during database creation, then data can be added.

Answer

Create Firestore database in native mode, then Enable Firestore API, then Add data to the database

Answer

Enable Firestore API, then Add data to the database, then Create Firestore database in native mode

Answer

Create Firestore database in native mode, then Add data to the database, then Enable Firestore API

Question 6

A team wants to implement automated testing for a Python application deployed on Cloud Run. They want the tests to run as part of the CI/CD pipeline after the image is built but before it is deployed. Which approach should they use?

Accepted Answer

Add a test step in Cloud Build that uses the built image to run integration tests before deploying. Cloud Build allows you to add a test step that runs the built container image before deploying it to Cloud Run. This ensures integration tests validate the application in an environment identical to production, catching issues early in the CI/CD pipeline. Running tests after the image is built but before deployment is a standard practice for shift-left testing.

Answer

Use Cloud Function to run tests triggered by a Pub/Sub message after the image is published

Answer

Run unit tests before building the image using Cloud Build, but skip integration tests

Answer

Deploy the image to a staging environment, run tests, and then promote to production

Question 7

A team is using Cloud Spanner and needs to query a secondary index with a STORING clause. What is the benefit of using STORING?

Accepted Answer

It avoids an index join (back to the base table). In Cloud Spanner, a secondary index normally stores only the indexed columns plus a reference to the base table's primary key. When a query needs columns not present in the index, Spanner must perform an index join (also called a back join) to fetch those columns from the base table. Adding a STORING clause copies the specified non-key columns directly into the index, so the query can be satisfied entirely from the index without touching the base table. This eliminates the extra lookup, reducing latency and read cost.

Answer

It creates a global index

Answer

It reduces storage costs

Answer

It allows the index to be used for ordering

Question 8

A company is migrating from Oracle to Cloud SQL for PostgreSQL using Database Migration Service. They need to ensure that the migration is validated before cutover. Which TWO actions should they take?

Accepted Answer

Run comparison queries (e.g., row counts, checksums) between source and target.. Option A is correct because running comparison queries such as row counts and checksums between the Oracle source and the Cloud SQL for PostgreSQL target is the standard way to validate data consistency and completeness before cutover, confirming that the migrated data matches the source. Option D is correct because performing load testing on the Cloud SQL instance using production data shape verifies that the target can handle the expected workload, query patterns, and concurrency, which is essential for validating the migration before switching over. Option B is not correct because taking a source snapshot is a backup or rollback precaution, not a migration validation action. Option C is not correct because disabling foreign key constraints is a performance or data-loading tactic, not a validation step, and it can compromise data integrity. Option E is not correct because shadow writes are a dual-write cutover or testing strategy, not a pre-cutover validation action, and they introduce complexity and consistency risks.

Answer

Take a snapshot of the source database before migration.

Answer

Disable foreign key constraints on the target to speed up migration.

Answer

Implement shadow writes from the application to both databases simultaneously.

Question 9

A data engineer needs to run a complex transformation pipeline between Cloud SQL and BigQuery, including joining data from both sources. The pipeline should run on a schedule and handle large volumes efficiently. Which service should they use?

Accepted Answer

Dataflow. Dataflow is the correct choice because it is a fully managed, serverless service for executing Apache Beam pipelines, which can handle complex transformations (e.g., joining data from Cloud SQL and BigQuery) at scale. It supports scheduled execution via Cloud Scheduler or built-in triggers, and its auto-scaling and exactly-once processing semantics ensure efficient handling of large volumes without manual infrastructure management.

Answer

Cloud Functions

Answer

Cloud Run

Answer

Datastream

Question 10

A company is migrating their on-premises SQL Server database to Cloud SQL for SQL Server. They need to ensure that schema changes are version-controlled and repeatable across environments. Which tool should they use?

Accepted Answer

Flyway. Flyway is a database migration tool that applies versioned, repeatable SQL migration scripts to a database, tracking each applied version in a schema history table. This makes schema changes version-controlled, deterministic, and reproducible across dev, test, and prod environments. Cloud SQL for SQL Server supports Flyway as a standard migration framework, so it directly satisfies the requirement.

Answer

Cloud Deployment Manager

Answer

Cloud Build

Answer

Database Migration Service

Question 11

A Cloud Spanner instance is experiencing high read latency. The instance has a single regional configuration. Monitoring shows high-priority CPU utilization is above 90%. What should the engineer do to reduce latency?

Accepted Answer

Increase the number of processing units. High-priority CPU utilization above 90% indicates that the instance's compute resources are saturated, causing queuing and increased read latency. Increasing the number of processing units (or nodes) adds more CPU capacity, allowing the instance to handle more concurrent reads and reducing latency. This directly addresses the root cause of resource contention.

Answer

Change the instance configuration to a multi-region setup

Answer

Reduce the number of indexes

Answer

Decrease the number of nodes to reduce contention

Question 12

A team is using Cloud SQL for MySQL and wants to recover the database to a specific point in time within the last 7 days. They have automated backups enabled. Which feature must be configured to enable point-in-time recovery (PITR)?

Accepted Answer

Enable binary logging and set a suitable binlog retention period. Cloud SQL for MySQL uses binary logging (the binlog) to capture all data changes, enabling point-in-time recovery (PITR) to any moment within the retention window. Automated backups alone only provide full backups at scheduled intervals; they do not capture the continuous stream of transactions needed to roll forward to a specific timestamp. Therefore, enabling binary logging and setting an appropriate binlog retention period is mandatory for PITR.

Answer

Use Database Migration Service for continuous replication

Answer

Configure cross-region replication

Answer

Enable automated backups only

Question 13

Match each command-line tool to its primary use.

Accepted Answer

gcloud: Primary interface for Google Cloud Platform. The correct matches are: gcloud for general GCP management, gsutil for Cloud Storage, kubectl for Kubernetes, and bq for BigQuery. Common confusions include mixing up gcloud with gsutil, or kubectl with bq.

Answer

gcloud: Manage Cloud Storage buckets and objects

Answer

kubectl: Run queries and manage BigQuery datasets

Question 14

A company is migrating a MySQL database with MyISAM tables to Cloud SQL for MySQL. They want to ensure the target database uses InnoDB for better transactional support and crash recovery. What should they do?

Accepted Answer

Run ALTER TABLE table_name ENGINE=InnoDB on each MyISAM table before migration.. Cloud SQL for MySQL supports only the InnoDB storage engine; MyISAM tables are not supported on the managed service. The correct pre-migration step is to convert each MyISAM table to InnoDB on the source using ALTER TABLE ... ENGINE=InnoDB (A), so the dump/import succeeds and the target gains transactional support and crash recovery. This conversion must happen before the migration, since Cloud SQL will reject or fail on MyISAM tables.

Answer

Set the default_storage_engine flag to InnoDB on the source MySQL instance.

Answer

Enable the skip_myisam flag in Cloud SQL to automatically convert MyISAM to InnoDB.

Answer

Use mysqldump with the --compatible=innodb option.

Question 15

Your mobile app uses Firestore to store user profiles. You need to restrict access so that users can only read/write their own data. Which Firestore feature should you use?

Accepted Answer

Security Rules. Firestore Security Rules are the correct choice because they allow you to define granular access controls based on user identity. By using the `request.auth.uid` variable in your rules, you can restrict read and write operations to documents where the user's UID matches a field in the document (e.g., `resource.data.user_id == request.auth.uid`), ensuring users can only access their own data.

Answer

Data Bundles

Answer

Composite indexes

Answer

IAM roles