PCDE Practice Test 48 — 15 Questions

Question 1

A startup is deploying a new Cloud SQL for PostgreSQL instance for a development environment. The team wants to minimize cost while ensuring that the instance can be quickly scaled up for production later. They also need to ensure that the instance is not publicly accessible. What should they do?

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

Accepted Answer

Create the instance with a shared-core machine type, disable public IP, and configure a private IP address.. For a cost-sensitive development environment, a shared-core machine type is the most economical choice. Disabling the public IP and configuring a private IP address ensures the instance is not exposed to the internet, which is a security best practice. The instance can be easily resized to a larger machine type when moving to production, providing scalability.

Answer

Configure the instance with a private IP address and enable the Cloud SQL Admin API.

Answer

Deploy the instance with a public IP address but restrict access using Cloud SQL Auth Proxy.

Answer

Use a dedicated-core machine type with high memory and enable automatic storage increase.

Question 2

A SaaS company runs AlloyDB for PostgreSQL with a primary instance and a read pool in the same region. They want the read pool to automatically take over as the new primary if the primary instance fails, with the shortest possible recovery time and no manual promotion. Which configuration should the database engineer use?

Accepted Answer

Create an AlloyDB high-availability (HA) configuration with a primary and a standby in different zones, and use the read pool for read scaling only.. AlloyDB high availability uses a primary and a standby in separate zones within the region, and the standby is promoted automatically when the primary fails, giving a short recovery time without manual intervention. The read pool is a separate scaling resource for read-only traffic and does not serve as the failover target. Combining HA for automatic takeover with a read pool for read scaling satisfies both availability and performance needs.

Answer

Add a second read pool in another zone and configure the application to switch read and write traffic to it when the primary fails.

Answer

Configure the read pool as a cross-region replica and rely on the application to promote it after a primary failure.

Answer

Enable point-in-time recovery on the primary and restore to a new instance if the primary fails.

Question 3

A startup is deploying a new application on Google Cloud. They need a fully managed, relational database that supports global transactions with strong consistency and horizontal scaling. The database must automatically handle sharding and replication without manual intervention. They expect rapid growth in users and data volume. Which Google Cloud database should they choose?

Accepted Answer

Cloud Spanner. Cloud Spanner is the only Google Cloud database that offers a fully managed, relational, globally distributed system with strong consistency and automatic horizontal scaling. It handles sharding and replication transparently, supporting global transactions without manual overhead. The other options lack either relational capabilities, global strong consistency, or automatic scaling.

Answer

Firestore

Answer

Cloud SQL for PostgreSQL

Answer

Cloud Bigtable

Question 4

Refer to the exhibit. You restored a Spanner database from a backup and are checking the status of the optimize operation. The operation has been running for 15 minutes and is 45% complete. The database is already accessible but queries on it are slower than expected. What should you do?

Accepted Answer

Continue running queries; performance will improve once the optimize operation completes.. Spanner's optimize operation runs asynchronously and does not block database access. Queries are slower during optimization because the operation reorganizes data and rebuilds indexes, which consumes I/O and CPU resources. Once the optimize operation completes, query performance will improve as the data layout becomes more efficient.

Answer

Wait for the operation to finish before allowing any queries.

Answer

Drop and restore the database again to start fresh.

Answer

Cancel the optimize operation to reduce resource usage.

Question 5

A healthcare company stores patient records in a Cloud Spanner database with a multi-region configuration (nam3) to ensure low latency and high availability across the United States. The database has a table with a monotonically increasing primary key based on a timestamp. The operations team notices that write latency has increased significantly and that CPU utilization on the leader region is consistently above 90%. They need to improve write performance without changing the application's data model. What should they do?

Accepted Answer

Change the primary key to use a UUID or a hash of the timestamp to distribute writes evenly across splits.. Cloud Spanner distributes data based on primary key ranges. A monotonically increasing key causes all writes to go to the last range, creating a hotspot on a single server. This leads to high CPU on the leader and increased write latency. Changing the key to a UUID or a hash of the timestamp distributes writes randomly, allowing Spanner to balance the load across multiple servers. Adding nodes or replicas does not fix the hotspot because the issue is key distribution, not overall capacity.

Answer

Enable Data Boost to offload read traffic from the leader region, freeing up CPU for writes.

Answer

Increase the number of replicas in the multi-region configuration to spread the write load.

Answer

Add more nodes to the Cloud Spanner instance to increase write throughput.

Question 6

A company runs a Cloud SQL for SQL Server 2019 Enterprise instance with 8 vCPUs and 52 GB of memory in us-east1. Their 3 TB database must be available with less than 30 seconds of downtime for a planned regional maintenance event that will restart the instance. They require the application to remain read-write throughout. Which configuration should they implement?

Accepted Answer

Enable high availability by adding a standby in a different zone, and rely on the automatic failover during the maintenance event.. High availability in Cloud SQL provisions a synchronous standby in a different zone of the same region. During a planned maintenance restart, the primary is failed over to the standby automatically, the instance keeps the same connection endpoint, and clients reconnect within seconds. This is the only listed option that preserves read-write access with sub-minute disruption, whereas replicas, backups, and exports either require manual steps or cause prolonged outages.

Answer

Configure the instance with a cross-region read replica in us-west1 and manually promote it during the maintenance window.

Answer

Export the database to a Cloud Storage bucket and import it into a new instance in another zone before the maintenance window.

Answer

Schedule the maintenance window during off-peak hours and take a manual backup immediately before the window begins.

Question 7

A developer wants to manually promote a release from a staging target to a production target using Cloud Deploy. Which gcloud command should they use?

Accepted Answer

gcloud deploy releases promote. The `gcloud deploy releases promote` command is the correct choice because Cloud Deploy uses a promotion-based model where releases are advanced through targets (e.g., staging to production) via a promote action. This command triggers the creation of a new rollout in the next target in the promotion sequence, effectively moving the release forward without manual rollout creation.

Answer

gcloud deploy releases approve

Answer

gcloud deploy rollouts create

Answer

gcloud deploy targets promote

Question 8

A startup is deploying a new Cloud SQL for PostgreSQL instance for a development environment. They want to minimize cost and do not require high availability or read replicas. Which machine type and configuration should they choose?

Accepted Answer

A shared-core machine type (e.g., db-f1-micro) with a single zone and no failover replica.. For a development environment with minimal cost and no HA requirement, a shared-core machine type in a single zone without a failover replica is the most economical choice. Dedicated-core types and high availability add cost without providing value for this use case. The startup should select the shared-core instance to keep expenses low while still having a functional PostgreSQL database.

Answer

A shared-core machine type (e.g., db-f1-micro) with high availability enabled across two zones.

Answer

A dedicated-core machine type (e.g., db-n1-standard-1) with a single zone and no failover replica.

Answer

A dedicated-core machine type (e.g., db-n1-standard-1) with high availability enabled across two zones.

Question 9

Refer to the exhibit. What is the most likely performance issue with this schema?

Accepted Answer

Hotspotting on TransactionId due to monotonically increasing values. The schema uses TransactionId as the partition key with monotonically increasing values (e.g., timestamps or auto-incrementing integers). In a distributed database like Cloud Spanner or Bigtable, this causes all writes to land on a single partition, creating a hotspot that throttles throughput and increases latency. The correct answer is C because this hotspotting is the most likely performance issue.

Answer

No performance issue; the schema is optimal

Answer

Hotspotting on UserId due to frequent queries

Answer

Too many secondary indexes causing write amplification

Question 10

A company runs a Cloud SQL for PostgreSQL instance with a 1 TB database. They need to enable point-in-time recovery (PITR) to be able to restore to any moment within the last 7 days. They also want to minimize the performance impact on the primary instance. What should they do?

Accepted Answer

Enable point-in-time recovery on the instance and configure the transaction log retention period to 7 days.. Point-in-time recovery in Cloud SQL for PostgreSQL is enabled by turning on PITR and setting the transaction log retention period. This allows restoration to any point within that period, up to 7 days. The feature uses asynchronous log archiving, so the performance impact on the primary is minimal. Other options either do not provide PITR or introduce unnecessary performance overhead.

Answer

Enable automated backups and set the retention period to 7 days.

Answer

Schedule a cron job to export the database every hour to Cloud Storage.

Answer

Create a read replica and enable binary logging on the primary.

Question 11

A team is deploying a Cloud Spanner instance for a new financial application. Their legal team requires that all data be stored within the European Union. The application will be accessed by users in Frankfurt and Paris, and the team wants the lowest possible read latency for both cities while meeting the data residency requirement. Which instance configuration should they choose?

Accepted Answer

A multi-region instance with the base region europe-west3 (Frankfurt) and the second region europe-west1 (Belgium).. Cloud Spanner instance configurations determine where replicas are placed. To keep data inside the European Union and serve Frankfurt and Paris with low read latency, the team needs a multi-region configuration whose regions are both within the EU, such as europe-west3 and europe-west1. A single-region instance would satisfy residency but not the latency goal, while any configuration including a non-EU region breaks the legal requirement.

Answer

A multi-region instance with the base region europe-west3 (Frankfurt) and the second region us-central1 (Iowa).

Answer

A regional instance in europe-west3 (Frankfurt).

Answer

A regional instance in europe-west1 (Belgium) with a read-only replica in europe-west3 (Frankfurt).

Question 12

A company runs a Cloud SQL for MySQL instance in us-central1 with 500 GB of data. Their compliance policy requires a daily full backup and point-in-time recovery to any second within the last 7 days. The current backup configuration retains only 7 automated backups and does not have binary logging enabled. They need to meet the compliance requirement with minimal operational overhead. What should they do?

Accepted Answer

Enable point-in-time recovery on the instance and set the retention period to 7 days.. Point-in-time recovery in Cloud SQL for MySQL uses binary logs to enable recovery to a specific timestamp. When enabled, it automatically manages binary logs and retention up to 7 days, satisfying the need for second-level recovery with minimal operational overhead. Other methods like mysqldump or manual binary logging require manual management and do not provide the same level of recovery granularity.

Answer

Enable binary logging on the instance and schedule a daily export using the Cloud SQL Admin API.

Answer

Configure a cron job to run mysqldump every hour and store the dumps in a Cloud Storage bucket with a 7-day lifecycle policy.

Answer

Create a read replica and use it for backups, then promote it to primary if recovery is needed.

Question 13

An engineer is configuring a cloudbuild.yaml file. They want two build steps (unit tests and linting) to run simultaneously, and after both complete, a third step (package) should run. How should they configure waitFor in the package step?

Accepted Answer

Set waitFor: ['-'] on the unit tests and linting steps, and waitFor: ['unit-tests', 'linting'] on the package step.. In Cloud Build, steps run sequentially by default. To run unit tests and linting in parallel, you set `waitFor: ['-']` on each of those steps, which tells Cloud Build they have no dependencies and can start immediately. Then, setting `waitFor: ['unit-tests', 'linting']` on the package step ensures it only runs after both parallel steps have completed successfully.

Answer

Do not set waitFor on any step.

Answer

Set waitFor: ['-'] on the package step.

Answer

Set waitFor: ['unit-tests', 'linting'] on all three steps.

Question 14

A social media platform uses Cloud SQL for PostgreSQL for its user and post data. The schema has a normalized design with separate 'users' and 'posts' tables. Queries that fetch a user's timeline (joining users and posts) are slow due to heavy read volume. The team wants to optimize the schema for this read-heavy workload without changing the application logic significantly. What schema design change is most appropriate?

Accepted Answer

Denormalize by embedding commonly accessed user fields (e.g., username, avatar URL) into the posts table.. Denormalizing by embedding frequently accessed user fields (username, avatar URL) into the posts table eliminates the join on every timeline read, which is the dominant query pattern. This trades a small amount of storage and write-time complexity for a large read-latency improvement, and it can be done without changing application logic significantly because the posts table still returns the needed fields.

Answer

Migrate to a NoSQL database like Firestore for better read performance.

Answer

Create a materialized view that joins users and posts, refreshed periodically.

Answer

Add GIN indexes on the posts table for faster full-text search.

Question 15

A healthcare company runs a Cloud SQL for PostgreSQL instance that stores patient records. Compliance requires that all data at rest be encrypted with a customer-managed encryption key (CMEK) that the security team can rotate and revoke independently. The team also needs to verify that the key is actually being used for the instance's data. Which approach meets these requirements?

Accepted Answer

Create a Cloud KMS key in the same region as the instance and configure the instance to use that key for CMEK.. Configuring a Cloud SQL instance with a Cloud KMS key in the same region enables CMEK, giving the security team control over rotation and revocation and allowing verification through KMS audit logs. Google-managed keys do not provide customer control, CSEK is not supported for Cloud SQL, and application-layer encryption does not cover all data at rest.

Answer

Enable encryption at the application layer before writing data to the database.

Answer

Enable default encryption with Google-managed keys and rely on Cloud KMS audit logs.

Answer

Use a customer-supplied encryption key (CSEK) stored in Cloud Storage for the instance.