PCD Deploy Scalable and Highly Available Databases in Google Cloud Practice Test 6 — 15 Questions

Question 1

A developer needs to connect to a Cloud SQL for PostgreSQL instance from a Compute Engine VM without adding the VM's IP to an authorized networks list. Which method should they use?

Accepted Answer

Use Cloud SQL Auth Proxy. The Cloud SQL Auth Proxy is the recommended method for securely connecting to a Cloud SQL instance from a Compute Engine VM without adding the VM's IP to an authorized networks list. It uses mutual TLS (mTLS) to authenticate and encrypt traffic, and it handles IAM-based authorization, so the VM only needs the Cloud SQL Client role and outbound access to the Cloud SQL API (port 443). This avoids exposing the database to the public internet or requiring static IP management.

Answer

Connect via Cloud Shell

Answer

Configure direct IP connection with SSL

Answer

Set up VPC peering and use private IP

Question 2

An organization needs a globally distributed relational database with strong consistency across regions and the ability to scale horizontally without manual sharding. Which Google Cloud database should they choose?

Accepted Answer

Cloud Spanner. Cloud Spanner is a globally distributed, strongly consistent relational database that scales horizontally. It supports multiple regional configurations and auto-scaling. Bigtable is not relational, Cloud SQL does not scale horizontally, and Firestore is not relational.

Answer

Firestore

Answer

Cloud SQL for MySQL

Answer

Cloud Bigtable

Question 3

A Cloud Bigtable instance has a single cluster. To improve availability and read throughput, the team decides to add a second cluster in a different zone. What is the effect on write performance?

Accepted Answer

Write latency increases due to replication across clusters. In Cloud Bigtable, adding a second cluster in a different zone enables replication across clusters. Writes must be replicated to all clusters to maintain consistency, which introduces additional network round-trips and acknowledgment overhead. This increases write latency because each write must be committed to both clusters before the client receives a success response.

Answer

Write performance remains unchanged

Answer

Write throughput doubles

Answer

Write latency decreases because of parallel replication

Question 4

A company wants to use Firestore security rules to allow users to read documents only if they are the owner (user ID matches the 'owner' field in the document). Which rule is correct?

Accepted Answer

allow read: if resource.data.owner == request.auth.uid;. The correct rule uses request.auth.uid to get the authenticated user's ID and resource.data.owner to compare against the document's owner field. The 'owner' field must exist and match the user ID.

Answer

allow read: if resource.data.uid == request.auth.token.email;

Answer

allow read: if request.auth.token.owner == resource.data.uid;

Answer

allow read: if request.auth.uid == 'owner';

Question 5

An engineer is deploying a Cloud SQL for SQL Server instance and wants to automatically increase storage when the disk usage reaches a threshold. Which flag should they set?

Accepted Answer

Enable 'automatic storage increase'. Cloud SQL supports the 'storage auto-increase' flag. When enabled, Cloud SQL automatically increases storage size in small increments when free space is low. This is set at instance creation or update.

Answer

Set 'disk size' to unlimited

Answer

Configure 'storage tier' to auto-scale

Answer

Use 'persistent disk auto-resize'

Question 6

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 7

A company needs to run AlloyDB for PostgreSQL with a read pool that can automatically scale based on load. They also need to run a local instance on-premises for disaster recovery. Which features should they use?

Accepted Answer

Use AlloyDB with auto-scaling read pool and AlloyDB Omni for on-premises. AlloyDB read pools support auto-scaling. For on-premises disaster recovery, AlloyDB Omni provides a downloadable version that can run on-premises and replicate from the cloud. Cross-region replication is for cloud-to-cloud, not on-premises.

Answer

Use AlloyDB with read replicas in the same region and Cloud SQL for on-premises

Answer

Use AlloyDB with a single instance and use Bigtable for on-premises

Answer

Use AlloyDB with cross-region replication to another cloud region

Question 8

To monitor Cloud SQL query performance, which metric should an engineer examine to see the rate of queries being executed?

Accepted Answer

database/queries. The metric 'database/queries' tracks the number of queries executed per second. CPU/memory/disk utilization metrics are resource-oriented, not query-oriented.

Answer

database/disk/bytes_used

Answer

database/memory/utilization

Answer

database/cpu/utilization

Question 9

A company is using Bigtable for real-time analytics and notices that certain row keys are causing hot spots. Which tool should they use to identify the hot spot patterns?

Accepted Answer

Key Visualizer. Bigtable Key Visualizer is designed to analyze access patterns and identify hot spots by visualizing row key distribution and traffic. It helps optimize row key design. The other options are general monitoring or optimization tools not specific to Bigtable key analysis.

Answer

Profiler

Answer

Cloud Monitoring workspace

Answer

Cloud Trace

Question 10

A developer wants to enable IAM database authentication for Cloud SQL for PostgreSQL. Which IAM role must be granted to a user or service account to allow login?

Accepted Answer

Cloud SQL Instance User. Cloud SQL IAM database authentication for PostgreSQL requires the Cloud SQL Instance User role (roles/cloudsql.instanceUser) to be granted to a user or service account. This role allows the principal to log in to the database instance using IAM credentials, while the Cloud SQL Admin, Connect, and Client roles do not grant the specific login privilege needed for IAM-based database authentication.

Answer

Cloud SQL Admin

Answer

Cloud SQL Connect

Answer

Cloud SQL Client

Question 11

An engineer needs to create a Cloud SQL instance with SSD storage. Which storage type should they select for best performance?

Accepted Answer

SSD (solid-state drive). Option D is correct because SSD (solid-state drive) is the recommended storage type for Cloud SQL instances when best performance is required. SSD provides lower latency and higher IOPS compared to HDD, making it suitable for transactional workloads and real-time applications. Cloud SQL supports both SSD and HDD, but SSD is the default and optimal choice for production databases.

Answer

HDD (hard disk drive)

Answer

Local SSD

Answer

Persistent disk standard

Question 12

A company is deploying a three-node Bigtable cluster for production. They anticipate growth in read throughput and want to plan for scaling. Which two actions can they take to increase read throughput? (Choose TWO.)

Accepted Answer

Add more nodes to the existing cluster. Adding nodes increases overall throughput, and adding a secondary cluster in a different zone allows reads to be served from both clusters, improving read throughput and availability. Changing to HDD would reduce performance. The development instance is not for production. Key Visualizer is for analysis only.

Answer

Switch to a development instance type

Answer

Change storage to HDD

Answer

Use Key Visualizer to increase performance

Question 13

A company has a Cloud Spanner instance with 1000 processing units and wants to enable auto-scaling. Which three parameters must be configured? (Choose THREE.)

Accepted Answer

Maximum processing units. When enabling auto-scaling for Cloud Spanner, you must set the minimum and maximum processing units (or nodes) and the target high-priority CPU utilization. Scaling increments and scaling limits are not direct parameters. The instance type is fixed.

Answer

Scaling increment (e.g., 100 units)

Answer

Instance type (regional or multi-region)

Question 14

An organization needs to secure Cloud SQL for MySQL instances. Which two measures should they implement to restrict network access? (Choose TWO.)

Accepted Answer

Enable SSL enforcement (require_ssl flag). Using Private IP restricts access to the VPC network, and enabling the 'require_ssl' flag ensures encrypted connections. IAM authentication controls user access but does not restrict network access. Public IP with authorized networks allows network access from authorized IP addresses but is still public. VPC Service Controls can restrict access, but the option is not listed; Private IP is the correct VPC-centric method.

Answer

Use IAM database authentication

Answer

Assign a public IP and configure authorized networks

Answer

Disable automatic storage increase

Question 15

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.