PCD Practice Exam 58 — 20 Questions

Question 1

An engineer needs to deploy Cloud Spanner with the ability to scale compute capacity automatically between 1000 and 6000 processing units based on load, with a target high-priority CPU utilization of 65%. Which configuration achieves this?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Create the instance with 1 node (1000 processing units) and enable autoscaling with min=1000, max=6000, target high-priority CPU=0.65.. Cloud Spanner auto-scaling uses processing units with min/max bounds and a high-priority CPU target. Nodes are fixed at 1000 processing units each, so auto-scaling with processing units is required to specify a range and target. The feature was introduced to allow finer-grained scaling than nodes.

Answer

Create the instance with 6 nodes (6000 processing units) and set autoscaling with min=1, max=6, target high-priority CPU=0.65.

Answer

Create the instance with 1000 processing units and enable autoscaling with min=1, max=6, target CPU=0.65.

Answer

Create the instance with 3 processing units and enable autoscaling with min=1000, max=6000, target CPU=0.65.

Question 2

A company runs a critical PostgreSQL database on Cloud SQL. They want to enforce that all client connections use SSL/TLS encryption. Which step is necessary to ensure this?

Accepted Answer

Set the 'require_ssl' flag to 'on' for the instance. Cloud SQL provides a server-side SSL certificate and optionally enforces encryption using the 'require_ssl' flag (or 'cloudsql.ssl_mode' in newer versions). IAM authentication does not enforce SSL. The Auth Proxy uses SSL by default but does not enforce it at the database level. Private IP alone does not encrypt traffic.

Answer

Enable IAM database authentication

Answer

Use the Cloud SQL Auth Proxy to connect

Answer

Assign a private IP address to the instance

Question 3

A company wants to run analytics queries on Cloud SQL data without impacting the transactional workload. They need to query the Cloud SQL database directly from BigQuery. Which BigQuery feature should they use?

Accepted Answer

BigQuery federated queries using Cloud SQL external table. BigQuery federated queries using Cloud SQL external tables allow you to query Cloud SQL databases directly from BigQuery without moving or replicating the data. This feature uses a federated query engine that pushes down SQL operations to Cloud SQL, minimizing the impact on the transactional workload by only reading the required data on demand.

Answer

Cloud SQL read replicas

Answer

Datastream to replicate Cloud SQL to BigQuery

Answer

BigQuery Omni

Question 4

A startup is building a mobile app with Firestore. They need to ensure that only authenticated users can read and write their own data. Which Firestore security rule pattern should they use?

Accepted Answer

Allow read/write if resource.data.userId == request.auth.uid. Using request.auth.uid to match the document owner ensures users can only access their own data.

Answer

Allow read/write if request.auth != null

Answer

Allow read/write only if the document path contains the user's uid

Answer

Allow read/write only if request.resource.data.userId == request.auth.uid

Question 5

A company needs to store and analyze large amounts of log data with flexible schema and support for real-time analytics. They want to use a fully managed, serverless solution. Which THREE Google Cloud services could meet their needs? (Choose three.)

Accepted Answer

Cloud Logging. BigQuery is a serverless data warehouse ideal for analyzing large volumes of log data with SQL-based analytics. Cloud Logging is a fully managed service for storing, querying, and analyzing log data in real time. Firestore is a serverless NoSQL document database with flexible schema and real-time listeners, suitable for storing semi-structured log data and enabling real-time dashboards. Cloud SQL for PostgreSQL is relational and not serverless, making it less suitable for log analytics. Cloud Spanner is a globally distributed relational database but is not serverless and is overkill for log storage and analysis. Therefore, the correct combination is Cloud Logging (A), Firestore (C), and BigQuery (E).

Answer

Cloud SQL for PostgreSQL

Answer

Cloud Spanner

Question 6

A team is designing a Cloud Bigtable schema for a time-series application that records sensor readings every second. They need to avoid write hotspots. Which row key design is most appropriate?

Accepted Answer

Use a composite key with sensor ID followed by reversed timestamp. To avoid hotspots, row keys should be designed to distribute writes across tablets. Using a composite key with sensor ID followed by reversed timestamp (e.g., `[sensor_id]#[reversed_timestamp]`) ensures that writes for different sensors go to different tablets, and even for the same sensor, the reversed timestamp spreads writes over multiple tablets rather than appending to the same tablet.

Answer

Use a salted timestamp where salt is the sensor ID modulo a small number

Answer

Use a UUID as the row key

Answer

Use a monotonically increasing timestamp as the row key

Question 7

A company wants to lift-and-shift an existing on-premises MySQL OLTP application to Google Cloud with minimal changes. They need up to 64 TB of storage and 96 vCPUs. Which database service should they use?

Accepted Answer

Cloud SQL for MySQL. Cloud SQL for MySQL supports up to 64 TB storage and 96 vCPU, and requires minimal changes for lift-and-shift. AlloyDB is PostgreSQL-compatible, not MySQL. Cloud Spanner is not a drop-in replacement for MySQL. BigQuery is for analytics.

Answer

Cloud Spanner

Answer

BigQuery

Answer

AlloyDB

Question 8

An application running on Cloud Run experiences cold starts causing latency spikes. What is the most cost-effective solution to reduce cold starts?

Accepted Answer

Set a minimum number of instances. Setting a minimum number of instances ensures that Cloud Run always keeps at least one instance warm (idle) to serve incoming requests instantly, eliminating cold start latency. This is the most cost-effective solution because you only pay for the minimum instances when they are idle (at a reduced rate), whereas other options increase per-request cost or do not address the root cause of cold starts.

Answer

Increase the container's CPU allocation

Answer

Enable HTTP keep-alive connections

Answer

Use a larger container memory size

Question 9

A developer wants to ensure that error logs from their Java application are automatically captured and grouped in Cloud Error Reporting. What is the recommended approach?

Accepted Answer

Instrument the application with the Error Reporting client library. The Error Reporting client library directly integrates with the application to automatically capture and group error logs, sending them to Cloud Error Reporting without requiring additional infrastructure. This is the recommended approach as it provides structured error reporting with automatic grouping, stack trace analysis, and real-time notifications.

Answer

Configure a log sink to Error Reporting

Answer

Export logs to BigQuery and then import to Error Reporting

Answer

Use a custom log-based metric to count errors

Question 10

A company is integrating a legacy application with Google Cloud using Cloud VPN. The application must be accessed from multiple remote offices over the internet. Which TWO technologies should the company use to ensure secure and reliable connectivity? (Choose TWO.)

Accepted Answer

Cloud VPN. Cloud VPN (Option E) is correct because it creates secure site-to-site VPN tunnels over the internet, allowing encrypted communication from each remote office. This meets the requirement for connectivity over the internet. Cloud Interconnect (Option A) is incorrect because it provides dedicated private connections, not over the internet, and does not satisfy the 'over the internet' requirement. Option B (Private Google Access) enables on-premises hosts to use private IPs to reach Google APIs, not for inter-site connectivity. Option C (Cloud NAT) enables outbound internet access from private instances, not for site-to-site. Option D (Direct Peering) provides direct connection between on-prem and Google but is not designed for hub-spoke topologies across multiple offices and also does not operate over the internet.

Answer

Cloud Interconnect

Answer

Private Google Access

Answer

Cloud NAT

Answer

Direct Peering

Question 11

A company is designing a disaster recovery strategy for a global e-commerce platform using Cloud Spanner. They need to ensure that the system can survive a regional outage with minimal data loss and automatic failover. Which TWO configurations should they choose? (Choose 2.)

Accepted Answer

Multi-region configuration with read-write replicas in at least two regions. A multi-region configuration with read-write replicas in at least two regions provides automatic failover and strong consistency with minimal data loss, meeting the DR requirements. Scheduled exports (C) and point-in-time recovery with daily backups (E) are manual processes that do not provide automatic failover and have higher data loss potential. Transactional replication to a second Cloud Spanner instance (D) is not a built-in feature of Cloud Spanner.

Answer

Regional configuration with a single replica

Answer

Set up scheduled exports and imports using Cloud Storage

Answer

Enable transactional replication to a second Cloud Spanner instance

Answer

Use point-in-time recovery with daily backups

Question 12

A data engineer is migrating a Teradata data warehouse to BigQuery. They need to transfer historical data and set up continuous replication. Which service should they use?

Accepted Answer

BigQuery Data Transfer Service. BigQuery Data Transfer Service supports scheduled and continuous transfers from Teradata to BigQuery, including incremental data loads.

Answer

Cloud Storage Transfer Service

Answer

Cloud Data Fusion

Answer

Database Migration Service

Question 13

A company's application on GKE is experiencing performance degradation. They want to use Google Cloud operations tools to identify the root cause. Which THREE tools should they use in combination?

Accepted Answer

Cloud Trace. Cloud Trace is correct because it provides distributed tracing capabilities that allow you to analyze latency across microservices in a GKE application. By collecting trace data from each request as it propagates through services, Cloud Trace helps identify performance bottlenecks, such as slow downstream calls or inefficient database queries, which are common causes of performance degradation.

Answer

Cloud Profiler

Answer

Cloud Debugger

Question 14

During a live migration from MySQL to Cloud SQL using DMS, the migration job enters a 'failed' state after the full dump. The error log indicates 'Binlog position out of bounds'. What is the most likely cause?

Accepted Answer

The source MySQL binary log retention period is too short.. DMS CDC requires that binary logs on the source are retained from the point of the full dump until cutover. If the binary logs are purged (e.g., by expiring logs or manual cleanup), the CDC phase cannot continue.

Answer

The Cloud SQL instance is not using InnoDB engine.

Answer

The DMS job is configured for one-time migration instead of continuous.

Answer

The source database has GTID mode disabled.

Question 15

A company plans to migrate a 200 GB Oracle database to Cloud SQL for PostgreSQL with minimal downtime. The source database has complex stored procedures and triggers. Which approach should the company use?

Accepted Answer

Use DMS with a continuous migration job, use Ora2Pg for schema conversion, and connect via Cloud SQL Auth Proxy.. Database Migration Service supports continuous migration with CDC for minimal downtime. Ora2Pg is used for schema conversion including stored procedures. Cloud SQL Auth Proxy provides secure connectivity without VPC peering.

Answer

Use DMS with a one-time migration job and schedule downtime.

Answer

Export the Oracle database to a dump file and import into Cloud SQL using pg_restore.

Answer

Use DMS with continuous migration but skip Ora2Pg; DMS automatically converts PL/SQL to PL/pgSQL.

Question 16

A company wants to migrate an on-premises PostgreSQL 9.6 database to Cloud SQL for PostgreSQL with minimal downtime. Which service should they use?

Accepted Answer

Database Migration Service. Database Migration Service (DMS) supports PostgreSQL migrations with continuous CDC for minimal downtime. It manages the full dump and incremental sync.

Answer

Cloud Dataflow

Answer

BigQuery Data Transfer Service

Answer

Cloud SQL Auth Proxy

Question 17

A company is migrating a critical on-premises PostgreSQL database to Cloud SQL. They need to test the migration with production data shape without affecting the source. What is the recommended testing strategy?

Accepted Answer

Use Database Migration Service to set up a continuous migration job and perform a dry run cutover.. Database Migration Service (DMS) supports continuous replication from the source PostgreSQL database to a Cloud SQL instance. By setting up a migration job and performing a dry run cutover, you can validate the entire migration process—including schema conversion, data consistency, and application compatibility—using actual production data without affecting the source database. This approach is recommended because it tests the end-to-end workflow and minimizes risk.

Answer

Run shadow writes from the application to both source and Cloud SQL concurrently.

Answer

Export the production data using pg_dump and import into a test Cloud SQL instance.

Answer

Use Cloud SQL's clone feature to create a copy of the source after migration.

Question 18

A team is developing a mobile backend API on Google Cloud. They are using Cloud Endpoints to manage API authentication and quotas. They want to monitor API performance including request count, latency, and error rates. They have enabled Cloud Endpoints logging but are not seeing detailed performance metrics in Cloud Monitoring. What should they do?

Accepted Answer

Enable Cloud Monitoring integration in Cloud Endpoints configuration.. Cloud Endpoints uses an Extensible Service Proxy (ESP) or Envoy proxy to intercept API calls and report metrics to Cloud Monitoring. By default, Endpoints logs requests but does not send detailed performance metrics (e.g., latency, request count, error rates) to Cloud Monitoring unless you explicitly enable the Cloud Monitoring integration in the Endpoints service configuration. Option B is correct because enabling this integration configures the proxy to emit those metrics directly to Cloud Monitoring.

Answer

Deploy a custom metrics exporter in the mobile app.

Answer

Install the Ops Agent on the API backend instances.

Answer

Use Cloud Logging to parse logs and create metric counters.

Question 19

A developer wants to allow a Compute Engine instance to send messages to a Pub/Sub topic. What is the recommended way to grant permissions?

Accepted Answer

Use the instance's default Compute Engine service account and assign the Pub/Sub Publisher role to it.. The default Compute Engine service account is automatically created for each project and attached to instances by default. By assigning the Pub/Sub Publisher role to this service account, the instance can authenticate and publish messages to a Pub/Sub topic without managing keys or credentials, following Google Cloud's recommended IAM best practices.

Answer

Generate an API key for the instance and include it in HTTP requests.

Answer

Create a service account and assign the Pub/Sub Publisher role; attach the service account to the instance.

Answer

Store the service account key file directly on the instance.

Question 20

An organization wants to create custom metrics based on application logs to track business KPIs. They need to ensure these metrics are available for alerting within minutes. Which approach should they use?

Accepted Answer

Write logs to Cloud Logging and use log-based metrics. Log-based metrics in Cloud Logging allow you to define custom metrics from log entries using filters or regular expressions. These metrics are ingested and available for alerting within minutes because they are processed in near real-time by the Cloud Monitoring backend, without requiring external data pipelines or custom code.

Answer

Export logs to BigQuery and use scheduled queries

Answer

Use OpenTelemetry collector to send metrics directly

Answer

Use Cloud Functions to parse logs and push custom metrics via API