PCD Practice Exam 51 — 20 Questions

Question 1

A company is migrating from Oracle to Cloud SQL for PostgreSQL. They have a stored procedure that uses Oracle's DBMS_OUTPUT.PUT_LINE for logging. How should they convert this to PostgreSQL?

Accepted Answer

Use RAISE NOTICE to output messages.. PostgreSQL does not have DBMS_OUTPUT. The equivalent is RAISE NOTICE, which sends messages to the client. Alternatively, they can log to a table using INSERT. RAISE is the most direct replacement. RAISE EXCEPTION is for errors, and dbms_output is not available.

Answer

Use RAISE EXCEPTION to output messages.

Answer

Use dbms_output package (installed via extension) to convert.

Answer

Use DBMS_OUTPUT.PUT_LINE as is; PostgreSQL supports it via the orafce extension.

Question 2

An organization is migrating a large Oracle database to Cloud SQL for PostgreSQL using Ora2Pg. They have complex PL/SQL packages with overloaded procedures. What is the correct approach to handle these packages in PostgreSQL?

Accepted Answer

Convert each Oracle package to a PostgreSQL schema containing the procedures and functions as individual objects.. PostgreSQL does not have packages. The recommended approach is to map each Oracle package to a separate schema containing the package's procedures and functions as top-level objects. Overloaded procedures can be handled by creating separate functions with different names or using default parameters. Ora2Pg can automate much of the conversion but manual review is needed.

Answer

Convert each package to a single PostgreSQL function containing all logic, using conditional logic to mimic overloaded procedures.

Answer

Keep the packages as is; PostgreSQL supports packages natively.

Answer

Use Oracle compatibility mode in PostgreSQL to enable package support.

Question 3

A team is planning to migrate a 500 GB MySQL database to Cloud SQL. The application can tolerate up to 2 hours of downtime. Which migration method should they choose?

Accepted Answer

Use a one-time migration job with Database Migration Service.. For a 500 GB database with a 2-hour downtime window, a one-time migration (offline) is sufficient because the dump and restore can complete within the window. Continuous migration is used for minimal downtime but adds complexity. Database Migration Service supports both one-time and continuous jobs.

Answer

Use mysqldump to export and import manually.

Answer

Use Cloud SQL replication to set up a read replica, then promote.

Answer

Use Database Migration Service with a continuous migration job.

Question 4

A company is migrating from Amazon Redshift to BigQuery. They need to stage the data in Amazon S3 before transferring to BigQuery. Which service should they use to automate the transfer?

Accepted Answer

BigQuery Data Transfer Service. BigQuery Data Transfer Service supports Redshift as a source and uses Amazon S3 as an intermediate staging location for the data transfer.

Answer

Cloud Storage Transfer Service

Answer

Database Migration Service

Answer

Cloud Data Fusion

Question 5

An e-commerce company is migrating its on-premises MySQL database to Cloud SQL. They require synchronous replication to a standby instance in the same region for automatic failover with zero RPO. Which Cloud SQL configuration should they use?

Accepted Answer

Create a Cloud SQL for MySQL HA instance in the chosen region. Cloud SQL HA instances use synchronous replication to a standby in a different zone within the same region, providing automatic failover and 0 RPO.

Answer

Use Cloud Spanner instead, as it provides built-in HA across regions

Answer

Deploy two standalone Cloud SQL instances and configure MySQL native replication between them

Answer

Create a Cloud SQL for MySQL instance with a read replica in a different region

Question 6

A company wants to create an SLO for their API with a target of 99.9% availability over a 30-day rolling window. They are using Cloud Monitoring. Which combination of resources and techniques should they use?

Accepted Answer

Create an uptime check and a log-based metric for errors. Use the SLI formula: (successful requests / total requests).. It combines an uptime check (to measure total requests) with a log-based metric for errors (to count failed requests), allowing the SLI formula (successful requests / total requests) to compute availability. This approach directly aligns with the 99.9% availability target over a 30-day rolling window, using Cloud Monitoring's native capabilities without external tools or irrelevant latency metrics.

Answer

Manually compute availability using external monitoring tools.

Answer

Use the Cloud Monitoring SLO service with a request latency SLI.

Answer

Use Cloud Trace to measure latency and create a custom metric.

Question 7

An engineering team is designing an AlloyDB cluster for an e-commerce platform. They anticipate variable read traffic and want to automatically add or remove read-only compute capacity based on CPU utilization. Which feature should they enable?

Accepted Answer

Read pool autoscaling. AlloyDB’s read pool autoscaling automatically adjusts the number of read pool instances based on metrics like CPU utilization. Query distribution is built-in, but autoscaling is the specific feature for capacity changes. Instance groups are a Compute Engine concept. Read replicas in Cloud SQL are not automatically scaled.

Answer

Enable query distribution across read pool instances.

Answer

Configure a managed instance group for the read pool.

Answer

Set up Cloud SQL read replicas with cross-region replication.

Question 8

A company uses Cloud Spanner for a global application. They want to improve read performance for point-reads (individual row lookups). Which TWO strategies should they adopt?

Accepted Answer

Create secondary indexes. Secondary indexes in Cloud Spanner allow point-reads to be served directly from the index table, avoiding a full table scan and reducing latency. Interleaved tables store child rows physically adjacent to their parent row, enabling efficient single-row lookups without cross-node coordination.

Answer

Use read replicas

Answer

Partition the table by time

Answer

Use batch reads

Question 9

A company uses Cloud Spanner with an instance configured with 1000 processing units. They notice that high-priority CPU utilization consistently exceeds 65% during peak hours, causing increased latency. They want to auto-scale based on this metric. Which scaling configuration should they use?

Accepted Answer

Use autoscaling with a minimum of 1000 processing units, a maximum of 2000 processing units, and a target high-priority CPU utilization of 65%. Cloud Spanner autoscaling uses processing units (not nodes) and allows setting a target for high-priority CPU utilization. Setting a minimum of 1000 processing units ensures a baseline, and a maximum of 2000 allows scaling up. The target high-priority CPU utilization (e.g., 65%) triggers scaling. Node-based options are not used with processing units.

Answer

Use autoscaling with a minimum of 1000 processing units, a maximum of 2000 processing units, and a target CPU utilization of 65%

Answer

Use autoscaling with a minimum of 1 node, a maximum of 2 nodes, and a target CPU utilization of 65%

Answer

Manually increase processing units to 2000

Question 10

An organization is migrating a critical application to Google Cloud and needs to ensure high availability and disaster recovery. The application runs on Compute Engine and uses a stateful database. Which three design choices should they make? (Choose three.)

Accepted Answer

Use managed instance groups distributed across multiple zones.. Managed instance groups (MIGs) distributed across multiple zones provide automatic failover and self-healing for the Compute Engine instances. If a zone fails, the MIG automatically recreates instances in healthy zones, ensuring high availability for the application layer. This aligns with Google Cloud's best practices for regional resilience.

Answer

Use preemptible VMs to reduce costs for the database layer.

Answer

Deploy all instances in a single zone and use snapshots for backup.

Question 11

A company is migrating a SQL Server database to Cloud SQL for SQL Server using Database Migration Service (DMS). They have created a continuous migration job with CDC. They need to test the migrated data before promotion without affecting the source. Which TWO actions should they take? (Choose 2 options.)

Accepted Answer

Use a separate DMS job to a different Cloud SQL instance for testing. Correct options: A and B. To test the migrated data without affecting the source database, you should either (A) use a separate DMS job to a different Cloud SQL instance specifically for testing, or (B) create a clone of the DMS target Cloud SQL instance and perform testing on that clone. Both approaches ensure the source remains unaffected. Option C is incorrect because stopping the DMS job would halt CDC and require re-synchronization. Option D is incorrect because testing directly on the DMS target instance could lead to data inconsistencies and is not recommended. Option E is incorrect because promoting the DMS job would make the target the primary, breaking the migration job and affecting the source.

Answer

Stop the DMS job, test on the target, then resume

Answer

Test directly on the DMS target instance without promotion; changes won't affect source

Answer

Promote the DMS job to make the Cloud SQL instance the primary, then re-create the job for production

Question 12

A company is designing a global e-commerce platform on Google Cloud. The application requires low-latency access for users worldwide and must be highly available. Which load balancing solution should they use?

Accepted Answer

External HTTP(S) Load Balancer. The External HTTP(S) Load Balancer is the correct choice because it is a global, proxy-based Layer 7 load balancer that terminates HTTP/HTTPS traffic at Google's edge points of presence (PoPs) and routes requests to the nearest healthy backend. This provides low-latency access for users worldwide by leveraging Google's global network and anycast IPs, while also offering built-in high availability, SSL offloading, and content-based routing.

Answer

External TCP/UDP Network Load Balancer

Answer

Cloud CDN

Answer

Internal TCP/UDP Load Balancer

Question 13

A company is designing a polyglot persistence architecture. They need to store (1) customer profiles with complex relationships and ACID transactions, (2) high-volume time-series IoT sensor data, and (3) interactive analytics dashboards. Which TWO Google Cloud databases should they choose for these workloads? (Choose 2 options.)

Accepted Answer

Cloud SQL. Cloud SQL (or Spanner) for relational ACID, Bigtable for time-series, BigQuery for analytics. The question asks for two, but three are mentioned; the best pair for the first two requirements is Cloud SQL and Bigtable. However, since it asks for TWO, we select Cloud SQL for transactions and Bigtable for time-series.

Answer

BigQuery

Answer

Firestore

Answer

Cloud Memorystore

Question 14

A company needs to migrate a self-managed PostgreSQL database (version 12) to Cloud SQL for PostgreSQL with minimal downtime. They plan to use Database Migration Service (DMS). What is the correct set of steps?

Accepted Answer

Create a DMS connection profile for the source; create a migration job with 'Full dump + CDC'; configure source for logical replication; promote destination when ready.

Answer

Create a DMS connection profile for the source; create a migration job with 'Full dump' only; promote the destination after dump completes.

Answer

Create a DMS connection profile for the source; set up Cloud SQL for PostgreSQL; use pg_dump and pg_restore manually.

Answer

Create a DMS connection profile for the source; create a migration job with 'CDC' only; no initial dump is needed.

Question 15

Which TWO strategies can be used to reduce cold start latency in Cloud Run? (Choose 2)

Accepted Answer

Set a minimum number of instances (min-instances) to keep instances warm.. Setting a minimum number of instances (min-instances) ensures that a specified number of container instances are always running and ready to serve requests, eliminating the cold start latency that occurs when an instance must be started from scratch. This pre-warming strategy directly reduces the time users wait for the first request to be processed.

Answer

Increase the maximum number of concurrent requests per instance.

Answer

Deploy the Cloud Run service in a region closer to the users.

Answer

Use a VPC connector to access resources in a VPC network.

Question 16

You are designing a Bigtable data model for an ad-tech platform that tracks user impressions. Which TWO row key design practices should you implement to avoid hotspots and ensure even distribution?

Accepted Answer

Use field promotion to place high-cardinality fields first. Field promotion places the highest-cardinality field first in the row key, which spreads writes across many tablet servers. In Bigtable, rows are sorted lexicographically by row key, so a high-cardinality prefix ensures that successive writes do not concentrate on a single tablet, avoiding hotspots.

Answer

Use monotonically increasing integers as the row key

Answer

Use a reversed timestamp as the first component

Answer

Use a low-cardinality field as the row key prefix

Question 17

A company is migrating an on-premises PostgreSQL database to Cloud SQL for PostgreSQL. They require automatic failover within 60 seconds in case of a zonal failure. The database must be available in the same region for low latency. Which configuration should they choose?

Accepted Answer

Create a Cloud SQL for PostgreSQL regional instance with HA configuration.. Cloud SQL HA configuration uses a regional instance with a standby in a different zone within the same region. Automatic failover occurs within 60 seconds. Zonal instances do not provide HA. Cross-region replicas are for disaster recovery, not automatic failover within the region.

Answer

Create a Cloud SQL for PostgreSQL zonal instance with one standby replica in the same zone.

Answer

Create a Cloud SQL for PostgreSQL instance with a local SSD and enable automatic storage increase.

Answer

Create a Cloud SQL for PostgreSQL zonal instance and add a cross-region read replica.

Question 18

A company uses Cloud Storage for backups. They need to comply with a regulation requiring immutable storage for 7 years. Which bucket configuration should they use?

Accepted Answer

Set a retention policy and lock the bucket. Locking a retention policy in Cloud Storage enforces immutable storage for the specified duration (7 years). Once locked, the retention policy cannot be removed or shortened, ensuring compliance with regulations that require data to be preserved in its original state and not modifiable or deletable until the retention period expires.

Answer

Use a bucket with a retention policy (not locked)

Answer

Set a lifecycle rule to archive to Coldline

Answer

Enable Object Versioning

Question 19

A financial services company is migrating from Oracle to Cloud SQL for PostgreSQL. They need to ensure data consistency during the migration and minimize downtime. Which two actions should they take? (Choose 2)

Accepted Answer

Use Database Migration Service with continuous migration (CDC) to replicate ongoing changes.. DMS continuous migration with CDC ensures minimal downtime by replicating changes. Connection profiles are necessary to configure source and target. Testing with DMS preview jobs is not a standard feature; DMS provides test jobs. Manual schema conversion is not recommended; use Ora2Pg.

Answer

Manually convert the Oracle schema to PostgreSQL using DDL statements.

Answer

Use DMS preview job to test migration before executing the full job.

Answer

Perform a full export using Oracle Data Pump and import directly into Cloud SQL.

Question 20

A retail company processes customer orders through a pipeline. New orders are written to a Cloud Storage bucket as JSON files. A Cloud Function (currently triggered directly by Cloud Storage finalize events) parses the order and sends it to a third-party fulfillment service via an HTTP POST. As order volume grows, the team observes that the Cloud Function often times out (60s default) because the fulfillment service is slow. The team wants to decouple the processing to improve reliability. The order must be attempted at least once, and if the fulfillment service fails, retries should be exponential with a maximum of 5 attempts. Which solution should the team implement?

Accepted Answer

Use Cloud Tasks to create a queue that targets the Cloud Function. Configure the queue with exponential backoff and max retries of 5. Set the Cloud Function trigger to be HTTP instead of Cloud Storage.. Cloud Tasks provides the exact retry semantics required: exponential backoff and a maximum of 5 retry attempts. By using an HTTP-triggered Cloud Function and a Cloud Tasks queue, the order processing is decoupled from the Cloud Storage event, allowing the function to return quickly and rely on Cloud Tasks to handle retries if the fulfillment service is slow or fails. This ensures at-least-once delivery with controlled retries. Option B is incorrect because increasing the timeout does not provide retries; the function would still block for up to 540 seconds without retrying on failure. Option C is suboptimal because Pub/Sub's push delivery retry configuration is less flexible than Cloud Tasks for HTTP endpoints, and it lacks built-in exponential backoff with a configurable max attempts without additional setup. Option D is inefficient because polling every 5 minutes introduces latency and does not provide real-time processing.

Answer

Keep the Cloud Storage trigger, but increase the Cloud Function timeout to 540 seconds and add retry logic in the function code.

Answer

Use Pub/Sub notifications from Cloud Storage to a Pub/Sub topic, with a subscription that pushes to the Cloud Function. Enable dead letter topics for failed deliveries.

Answer

Replace the Cloud Function with a Cloud Run job that polls Cloud Storage for new files and sends orders to the fulfillment service. Use Cloud Scheduler to run the job every 5 minutes.