PCDE Practice Test 22 — 15 Questions

Question 1

Refer to the exhibit. After creating this Bigtable instance, the administrator noticed high read latency during peak hours. Which configuration change would most likely help?

Accepted Answer

Increase cluster-num-nodes to at least 5. Option D is correct because increasing the initial number of nodes (from 3 to a higher value) provides more serving capacity to handle read load. Option A (increasing max nodes) only allows scaling up but does not increase baseline capacity. Option B (HDD) would worsen latency. Option C (adding clusters) adds replication overhead but does not directly improve read latency for the existing cluster.

Answer

Change cluster-storage-type to HDD

Answer

Add more clusters in different zones

Answer

Increase cluster-autoscaling-max-nodes to 20

Question 2

A Cloud Spanner database is experiencing high CPU utilization on one node. Users report slow queries. The table uses a UUID primary key. What is the most effective action?

Accepted Answer

Use a hash key prefix to distribute writes.. A hash key prefix can distribute writes more evenly across nodes, preventing hot spots that cause high CPU on a single node. Adding nodes may not resolve a hot spot.

Answer

Add a database index on frequently queried columns.

Answer

Convert the UUID to a monotonically increasing integer.

Answer

Increase the number of nodes in the instance.

Question 3

A financial institution requires all data stored in Cloud Spanner to be encrypted using customer-managed encryption keys (CMEK) stored in Cloud KMS. The security team mandates that the key be in a separate project from the Spanner instance. How should the database engineer configure this?

Accepted Answer

Grant the Cloud Spanner service account the Cloud KMS CryptoKey Encrypter/Decrypter role on the key.. Option B is correct because Cloud Spanner uses a service account to access Cloud KMS keys. To enable customer-managed encryption keys (CMEK) from a separate project, the Cloud Spanner service account must be granted the Cloud KMS CryptoKey Encrypter/Decrypter role on the specific key. This allows Spanner to encrypt and decrypt data using the key without granting broader permissions.

Answer

Grant the Cloud Spanner service account the Editor role in the key project.

Answer

Specify the key in the Spanner instance creation and provide the user's credentials for KMS access.

Answer

Grant the Spanner instance's service account the Cloud KMS Admin role on the key.

Question 4

Which THREE actions can reduce read latency for a globally distributed Cloud Spanner database?

Accepted Answer

Use read-only replicas (follower reads). Option A is correct because read-only replicas (follower reads) allow Cloud Spanner to serve read requests from non-leader replicas, reducing the distance data must travel and thus lowering read latency for globally distributed users. This is particularly effective when strong consistency is not required, as follower reads can return data that is up to a few seconds stale but much faster to access from a nearby replica.

Answer

Use leader reads

Answer

Use interleaved tables

Question 5

A Cloud SQL for PostgreSQL instance is experiencing high CPU usage due to many short-lived connections. Which configuration change can help without application changes?

Accepted Answer

Enable connection pooling with pgBouncer. Option B is correct because enabling connection pooling with pgBouncer reduces the CPU overhead of creating and tearing down connections. Option A (read replicas) helps with read load, not CPU from connections. Option C (increase max_connections) may worsen the issue. Option D (increase tier) increases cost but may not address the root cause of connection churn.

Answer

Use read replicas

Answer

Increase the max_connections parameter

Answer

Increase the tier to more vCPUs

Question 6

A company uses Memorystore for Redis as a cache. They need to survive a zone failure. Which configuration should they choose?

Accepted Answer

Standard tier with replication. Standard tier with replication (Option D) provides a primary-replica pair in the same region but across two zones, ensuring automatic failover if one zone fails. This meets the requirement to survive a zone failure while maintaining low-latency access within a single region.

Answer

Cluster tier with multiple shards

Answer

Basic tier with a single node

Answer

Standard tier cross-region

Question 7

You are designing a highly available Cloud SQL for MySQL architecture. Which TWO components are essential?

Accepted Answer

High availability (HA) configuration with a standby zone. A is correct because Cloud SQL for MySQL High Availability (HA) configuration provisions a standby instance in a different zone within the same region, enabling automatic failover with minimal downtime. B is correct because regional persistent disks replicate data synchronously across two zones, ensuring data durability and availability even if an entire zone fails, which is a prerequisite for HA.

Answer

Point-in-time recovery (PITR)

Answer

Read replicas in the same region

Answer

Cross-region replication

Question 8

A company plans to migrate an on-premises MySQL database to Cloud SQL. Which THREE steps should they include in their migration plan?

Accepted Answer

Test application compatibility with Cloud SQL.. Option A is correct because testing application compatibility with Cloud SQL ensures that any MySQL-specific features, configurations, or behaviors used by the application are supported in the Cloud SQL environment. This step is critical to identify potential issues early, such as unsupported storage engines, character set differences, or version-specific SQL syntax, before committing to the full migration.

Answer

Convert all stored procedures to PostgreSQL dialect.

Answer

Enable point-in-time recovery before migration.

Question 9

A company has a Cloud SQL instance with a 500 GB database. They need to perform a major version upgrade from MySQL 5.7 to 8.0 with minimal downtime. Which strategy should they use?

Accepted Answer

Create a read replica with new version, then promote. Creating a read replica with the new MySQL version and then promoting it minimizes downtime because replication keeps the replica synchronized with the primary until promotion. This approach avoids the lengthy export/import process and reduces the risk of data loss or extended unavailability.

Answer

Export and import the database

Answer

Use in-place upgrade via gcloud command

Answer

Upgrade during maintenance window

Question 10

A Cloud SQL instance stores financial data. They need to meet a 1-hour RPO and 30-minute RTO. What backup configuration should they use?

Accepted Answer

Automatic backups plus binary logging to enable point-in-time recovery (PITR).. Option B is correct because automatic backups combined with binary logging enable point-in-time recovery (PITR), which allows restoring the database to any point within the backup retention period. This configuration meets the 1-hour RPO by recovering transactions committed within the last hour, and the 30-minute RTO by using the most recent full backup plus binary logs to restore quickly.

Answer

Export once a day to Cloud Storage.

Answer

Enable high availability.

Answer

Automatic backups with a schedule of 1 hour.

Question 11

Refer to the exhibit. This DDL is used to create a table in Cloud Spanner. The table will be used for storing user data with high write throughput. What is one performance issue with this table design?

Accepted Answer

The primary key is a monotonically increasing integer. Option A is correct because a monotonically increasing primary key (UserId) causes hot spots as all writes concentrate on the last split. Option B (STRING(MAX)) is acceptable but not a performance issue. Option C (no indexes) is not required for write throughput. Option D (not interleaved) is irrelevant.

Answer

The Name column is of type STRING(MAX)

Answer

There are no secondary indexes

Answer

The table is not interleaved with another table

Question 12

Refer to the exhibit. The company wants to achieve a 99.99% SLA for this Cloud SQL instance. What should they do?

Accepted Answer

Change the availability type to REGIONAL.

Answer

Change to a different tier.

Answer

Enable automatic backups.

Answer

Increase the number of CPUs.

Question 13

A developer reports that their application cannot connect to a Cloud SQL instance using private IP, but public IP works. The Cloud SQL instance is in VPC peering with the application's VPC. The application is in the same region. What is the most likely cause?

Accepted Answer

The private IP range of the Cloud SQL instance conflicts with the application's VPC.. Option B is correct because when a Cloud SQL instance is configured with a private IP address that overlaps with the application's VPC CIDR range, the VPC peering connection cannot route traffic correctly. This is due to the fact that VPC peering requires non-overlapping IP ranges to establish proper routing tables; overlapping ranges cause route conflicts and connectivity failures. Since public IP works, the issue is isolated to private IP routing, making IP range conflict the most likely cause.

Answer

The VPC peering connection is not established.

Answer

The Cloud SQL proxy is not running.

Answer

The Cloud SQL instance has 'require SSL' enabled.

Question 14

A manufacturing company is deploying a time-series database for sensor data on Cloud Bigtable. They expect 100 TB of data per year and need low-latency reads on row keys within the last hour. Which TWO design choices should they make?

Accepted Answer

Use a reverse timestamp in the row key so that recent data is at the beginning of the table.. Options A (salting) and D (reverse timestamp row keys) are correct. Salting distributes writes, and reverse timestamps allow recent data to appear first, improving read latency for recent rows. Option B is wrong because storing data across multiple tables adds overhead. Option C is wrong because row keys should not be too long. Option E is wrong because Bigtable is designed for high throughput; limiting to 1000 QPS is unnecessary.

Answer

Set the maximum QPS to 1000 to avoid overloading the cluster.

Answer

Partition the data into separate tables for each month.

Answer

Design row keys to be as long as possible to avoid collisions.

Question 15

A developer needs a local development database that mirrors a Cloud SQL instance. What is the best practice?

Accepted Answer

Export data and import to local MySQL. Option C is correct because exporting the Cloud SQL instance data (e.g., using `gcloud sql export sql` or `mysqldump`) and importing it into a local MySQL database creates an exact, offline replica of the production schema and data. This allows the developer to work with a full, consistent dataset without network latency, connection overhead, or dependency on Cloud SQL availability, which is the standard best practice for local development mirrors.

Answer

Use Cloud SQL Proxy to connect locally

Answer

Use Cloud Functions

Answer

Use Cloud SQL's public IP

PCDE Practice Test 22 — 15 Questions

Exhibit

PCDE Practice Test 22 — 15 Questions

Exhibit