PCDE Practice Test 15 — 15 Questions

Question 1

Your company runs a global e-commerce platform on Cloud Spanner. You need to capture real-time changes to a table (e.g., orders) and stream them to a downstream analytics pipeline in near real-time. Which TWO Google Cloud features or services should you combine to achieve this? (Choose two.)

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

Accepted Answer

Dataflow streaming pipeline. A Dataflow streaming pipeline can consume Cloud Spanner change streams in near real-time, process the data (e.g., transform, filter, aggregate), and write it to a downstream analytics system. Dataflow provides exactly-once processing semantics and auto-scaling, making it ideal for continuous change data capture (CDC) pipelines.

Answer

Cloud Functions

Answer

Cloud Pub/Sub

Answer

Cloud SQL for PostgreSQL

Question 2

A company wants to enforce least-privilege IAM for their DevOps team. They need to grant permissions to manage Compute Engine instances but not to delete them. Which TWO approaches should they use?

Accepted Answer

Use a predefined role with an IAM condition that denies delete operations.. Predefined roles like `roles/compute.instanceAdmin.v1` include delete permissions. Custom roles allow fine-grained selection of specific permissions. Predefined roles with conditions can restrict actions (e.g., prevent delete), but conditions can be complex. The simplest is to create a custom role with only the required permissions (e.g., compute.instances.create, etc., but not delete).

Answer

Grant the `roles/compute.instanceAdmin.v1` role.

Answer

Grant the `roles/owner` role at the project level.

Answer

Grant the `roles/compute.admin` role.

Question 3

An engineer is designing a Cloud SQL database for an e-commerce platform. They need to store product inventory and order history. Which schema normalization level is recommended for OLTP to avoid data anomalies?

Accepted Answer

Third Normal Form (3NF). Third Normal Form (3NF) is the recommended normalization level for OLTP systems to avoid data anomalies while maintaining practical query performance. 3NF eliminates transitive dependencies, ensuring that non-key attributes depend only on the primary key, which reduces redundancy and update anomalies. While higher normal forms exist, 3NF is a standard target for transactional databases.

Answer

Second Normal Form (2NF)

Answer

First Normal Form (1NF)

Answer

Denormalized schema

Question 4

A team uses Cloud Deploy with a delivery pipeline that has multiple targets (dev, staging, prod). They want to automatically roll back to the previous release if the new release fails a post-deployment health check. Which configuration should they use?

Accepted Answer

Configure a postDeploy hook that runs a health check and uses 'gcloud deploy releases rollback' if it fails. Cloud Deploy does not have a built-in 'rollbackOnFailure' or 'auto-rollback' property for post-deployment health checks. Instead, you must implement a custom postDeploy hook that runs a health check script; if the health check fails, the script can invoke 'gcloud deploy releases rollback' to programmatically trigger a rollback to the previous release. This gives you full control over the rollback logic and conditions.

Answer

Set 'rollbackOnFailure: true' in the pipeline definition

Answer

Use a canary deployment with metric analysis to trigger rollback

Answer

Enable 'auto-rollback' in the target configuration

Question 5

A company collects sensor data from millions of devices globally. Each write is a small record with a device ID and timestamp. They need low write latency and high availability. Which database should they choose?

Accepted Answer

Cloud Bigtable. Cloud Bigtable is a fully managed, scalable NoSQL database designed for large analytical and operational workloads with high throughput and low latency. It supports millions of writes per second from globally distributed devices, provides high availability through replication, and is optimized for time-series data like sensor records with device IDs and timestamps.

Answer

Cloud Firestore

Answer

Cloud Memorystore

Answer

Cloud SQL for MySQL

Question 6

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. Using a monotonically increasing integer as the primary key in Cloud Spanner causes all writes to be directed to a single split (tablet), creating a hotspot that severely limits write throughput. Cloud Spanner distributes splits across nodes based on key ranges, and sequential keys prevent this distribution, leading to performance degradation under high write load.

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 7

A company uses Cloud Spanner with a schema that has a table 'Orders' with primary key (CustomerId, OrderDate, OrderId). They notice hotspots on a specific customer. Which schema change would best distribute load?

Accepted Answer

Add a hash of CustomerId as a prefix to the primary key.. Adding a hash of CustomerId as a prefix to the primary key distributes writes across multiple key ranges, preventing hotspots on a single customer. Cloud Spanner splits data by primary key ranges, so a monotonically increasing or heavily skewed key like CustomerId causes all writes for that customer to hit one split. Hashing the prefix randomizes distribution.

Answer

Use a secondary index on CustomerId.

Answer

Split the table into multiple tables per region.

Answer

Change primary key to OrderId only.

Question 8

A company is migrating an Oracle database to Cloud SQL for PostgreSQL using Ora2Pg for schema conversion. After conversion, they want to test the correctness of converted stored procedures. Which tool should they use?

Accepted Answer

pgTAP. pgTAP is a unit testing framework for PostgreSQL that allows writing tests for functions, procedures, and other database objects.

Answer

Database Migration Service validation

Answer

Ora2Pg --test flag

Answer

Cloud SQL Insights

Question 9

An e-commerce platform uses Cloud Spanner as its database. The orders table has a monotonically increasing order_id as the primary key, and the team observes high write latency during peak hours. Which design change would BEST distribute write load across nodes?

Accepted Answer

Change the primary key to a UUID string. Cloud Spanner physically orders rows by primary key, so a monotonically increasing order_id concentrates all new inserts at the end of the key space, creating a hot spot on a single split (and thus a single node). Changing the primary key to a UUID string (or a hash-prefixed key) randomizes insert distribution across splits, spreading write load across many nodes and eliminating the hot spot.

Answer

Add a secondary index on order_id

Answer

Increase the number of nodes

Answer

Use interleaving with a parent table

Question 10

An organization uses Terraform to manage infrastructure across multiple teams. They want to implement a branching strategy that supports rapid iteration and continuous integration for infrastructure changes while ensuring that the main branch always reflects the desired state. Which Git branching model is most aligned with GitOps principles for IaC?

Accepted Answer

Trunk-based development with short-lived feature branches and automated CI/CD pipelines that apply changes upon merge to main.. Trunk-based development with short-lived feature branches and automated CI/CD that applies changes on merge to main aligns with GitOps because main is the single source of truth and the desired state. Merges trigger pipelines that reconcile infrastructure, enabling rapid iteration and continuous integration. This keeps main always deployable and reflects the intended state.

Answer

Feature branching with long-lived branches for each environment (dev, staging, prod).

Answer

Each team maintains its own fork and periodically submits pull requests to a central repository.

Answer

GitFlow with separate branches for develop, release, and hotfixes.

Question 11

A company is running analytical queries on large datasets (terabytes) that involve aggregations, joins, and window functions. The data is updated daily via batch loads. The queries must complete in seconds to minutes. Which Google Cloud database service is BEST suited for this workload?

Accepted Answer

BigQuery. BigQuery is a serverless, highly scalable enterprise data warehouse designed for analytical workloads on massive datasets. It uses columnar storage and a distributed query engine (Dremel) to execute complex aggregations, joins, and window functions efficiently over terabytes of data, returning results in seconds to minutes. Daily batch loads are easily handled via native ingestion or the Storage Write API, and separation of storage and compute allows independent scaling.

Answer

Cloud SQL for MySQL

Answer

Cloud Spanner

Answer

Bigtable

Question 12

Match each Google Cloud database service to its primary use case.

Accepted Answer

Cloud SQL: Relational database for standard workloads. The correct matches are Cloud SQL for standard relational workloads, Cloud Spanner for globally distributed transactions, and Bigtable for analytical workloads. Firestore is for mobile/web apps, and Memorystore is for caching. Common mistakes include confusing the use cases of these services.

Answer

Firestore: Horizontally scalable relational database for global transactions

Answer

Memorystore: Relational database for standard workloads

Question 13

Arrange the steps to set up database encryption with Cloud KMS for Cloud SQL.

Accepted Answer

1. Create KMS key ring and key. 2. Grant Cloud SQL service account access to the KMS key. 3. Create Cloud SQL instance with CMEK. 4. Verify encryption and test.. First create KMS key, grant access, then create instance with CMEK, verify, test.

Answer

1. Grant Cloud SQL service account access to the KMS key. 2. Create KMS key ring and key. 3. Create Cloud SQL instance with CMEK. 4. Verify encryption and test.

Answer

1. Create Cloud SQL instance with CMEK. 2. Create KMS key ring and key. 3. Grant Cloud SQL service account access to the KMS key. 4. Verify encryption and test.

Answer

1. Create KMS key ring and key. 2. Create Cloud SQL instance with CMEK. 3. Grant Cloud SQL service account access to the KMS key. 4. Verify encryption and test.

Question 14

Arrange the steps to configure high availability for a Cloud SQL for MySQL instance.

Accepted Answer

Step 1: Create a Cloud SQL for MySQL instance. Step 2: Enable high availability and configure the standby zone. Step 3: Verify high availability and test failover.. Create instance first, then enable HA and set standby zone, then verify and test.

Answer

Step 1: Enable high availability and configure the standby zone. Step 2: Create a Cloud SQL for MySQL instance. Step 3: Verify high availability and test failover.

Answer

Step 1: Create a Cloud SQL for MySQL instance. Step 2: Verify high availability and test failover. Step 3: Enable high availability and configure the standby zone.

Answer

Step 1: Enable high availability and configure the standby zone. Step 2: Verify high availability and test failover. Step 3: Create a Cloud SQL for MySQL instance.

Question 15

An organization wants to implement GitOps for their GKE clusters. They need to automatically sync the cluster state with a Git repository. Which Google Cloud service should they use?

Accepted Answer

Config Sync. Config Sync is Google Cloud's GitOps service that continuously reconciles the state of GKE clusters with configuration stored in a Git repository. It is designed specifically for this purpose, providing automated sync, drift detection, and policy enforcement. Therefore, Config Sync is the correct choice for implementing GitOps on GKE.

Answer

Argo CD

Answer

Cloud Build

Answer

Cloud Source Repositories