PCDE Practice Test 9 — 10 Questions

Question 1

A data engineer is migrating a legacy on-premises Oracle data warehouse to Google Cloud. The source schema uses star schemas and advanced Oracle features like materialized views. The target must support real-time data from streaming sources and run complex SQL joins over 50 TB of data with low latency. Which architecture is most appropriate?

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

Accepted Answer

Migrate to BigQuery and use streaming inserts for real-time data.. BigQuery is the most appropriate target because it supports real-time streaming inserts, can handle complex SQL joins over 50 TB of data with low latency via its columnar storage and distributed query engine, and can replace Oracle materialized views with logical views or scheduled queries. It also natively integrates with streaming sources like Pub/Sub, making it ideal for the real-time data requirement.

Answer

Migrate to AlloyDB and use columnar engine for analytics.

Answer

Migrate to Cloud Spanner and use its analytics interface.

Answer

Migrate to Cloud SQL for PostgreSQL and use read replicas for analytics.

Question 2

A company is using Cloud Bigtable to store user events for real-time analytics. The current row key is userId_timestamp (e.g., user123_20240115103000). However, writes to the table are unevenly distributed, causing hotspotting on a few nodes. Which row key modification can best distribute writes evenly?

Accepted Answer

Add a hash prefix (e.g., 2-byte hash of userId) at the beginning.. Adding a hash prefix (e.g., a 2-byte hash of the userId) at the beginning of the row key ensures that writes are distributed across all Bigtable nodes by randomizing the initial portion of the key. This prevents hotspotting because sequential or clustered userId values no longer concentrate writes on a single tablet server, as Bigtable splits and distributes rows based on the row key prefix.

Answer

Increase the number of nodes to handle the load.

Answer

Reverse the timestamp and prepend it to the key.

Answer

Move userId to the end of the row key.

Question 3

Your team is migrating a 5 TB MySQL database from on-premises to Cloud SQL. The database receives 2,000 writes per second and the network link has 500 Mbps bandwidth. You need to minimize migration time with zero data loss. What should you do?

Accepted Answer

Configure Database Migration Service with a connectivity test and start continuous replication.. Database Migration Service (DMS) with continuous replication is the correct choice because it supports live migration with minimal downtime and zero data loss for large databases like 5 TB. DMS uses MySQL binlog-based replication to synchronize changes from the on-premises source to Cloud SQL while the source remains operational, then performs a cutover with only seconds of downtime. This approach handles the 2,000 writes/second load and 500 Mbps bandwidth efficiently by streaming incremental changes rather than transferring the entire 5 TB in one shot.

Answer

Export the database using mysqldump and import into Cloud SQL using the console.

Answer

Use gcloud sql import with a compressed CSV export from on-premises.

Answer

Set up a VPN, then use mysqldump with --master-data and pipe to mysql on Cloud SQL.

Question 4

A company is migrating an Oracle database to Cloud SQL for PostgreSQL. They have a table with a column defined as NUMBER(10,2). To maintain data integrity, what should be the corresponding PostgreSQL data type?

Accepted Answer

NUMERIC(10,2). NUMBER(10,2) represents a decimal number with 10 digits total and 2 after decimal; NUMERIC(10,2) is the equivalent in PostgreSQL.

Answer

FLOAT

Answer

INTEGER

Answer

DECIMAL(10,0)

Question 5

You need to transfer 10 TB of data from on-premises servers to Cloud Storage for loading into Bigtable. Which method is the most efficient and reliable for this volume?

Accepted Answer

Use Storage Transfer Service. The Storage Transfer Service is designed for large-scale, online data transfers from on-premises or other cloud providers to Google Cloud. It handles 10 TB efficiently by automatically managing retries, checksums, and network optimization without requiring manual scripting or persistent VPN connections, making it the most reliable and efficient choice for this volume.

Answer

Set up Cloud VPN and use rsync

Answer

Use gsutil cp in parallel

Answer

Use Dataflow to read and write data

Question 6

A Database Engineer is responsible for managing a Cloud SQL for MySQL instance. The engineer needs to ensure that automated backups are retained for 14 days and that point-in-time recovery (PITR) is enabled. Which configuration should the engineer set?

Accepted Answer

Enable automated backups, set backup retention to 14 days, and enable binary logging.. Enabling automated backups with a 14-day retention ensures backup files are kept for the required duration, and enabling binary logging (which is required for PITR) allows point-in-time recovery by replaying transaction logs against a base backup. In Cloud SQL for MySQL, PITR is not automatically enabled with automated backups; binary logging must be explicitly enabled.

Answer

Create scheduled manual backups each day and retain them for 14 days; PITR is not needed because backups are daily.

Answer

Enable automated backups with a retention of 14 days; PITR is automatically enabled.

Answer

Enable automated backups with 14-day retention and set up a cross-region replica for disaster recovery.

Question 7

A company uses Cloud SQL for MySQL with a failover replica. The primary instance is in us-central1 and the replica is in us-east1. During a regional outage in us-central1, the database engineer executes an emergency failover to the replica. After the failover, applications experience high latency when writing to the new primary. What is the most likely cause?

Accepted Answer

The new primary is in a different region, causing higher network round-trip times for applications that are still in us-central1.. After a cross-region failover, the new primary resides in us-east1 while the applications remain in us-central1. This geographic distance increases network round-trip time (RTT) for write operations, as each write must traverse the WAN between regions. Cloud SQL for MySQL does not automatically relocate compute resources, so latency-sensitive applications will experience higher write latency until they are migrated or configured to connect to the new region.

Answer

Cross-region replication triggers a mandatory 1-hour delay before writes are allowed.

Answer

The failover did not complete successfully; the replica is still in read-only mode.

Answer

The replica had a replication lag of 5 minutes, causing data inconsistency.

Question 8

A DevOps team is designing a landing zone in Google Cloud. They need to set up a folder structure that supports multiple teams and environments. Which TWO practices should they follow? (Choose 2)

Accepted Answer

Create separate folders for each team (e.g., 'Team-A', 'Team-B') under the environment folders.. Option D is correct because creating environment folders such as prod, staging, and dev under the organization or a top-level folder lets you apply distinct IAM policies, organization policies, and billing/quota controls per environment, achieving strong isolation between production and non-production workloads. Option C is correct because nesting separate team folders (e.g., Team-A, Team-B) under each environment folder maps the resource hierarchy to both organizational and environmental boundaries, so permissions and policies can be inherited and scoped precisely at the team level within each environment. Option A is not appropriate because organization policies are best applied at higher nodes (organization, folder) so they inherit down; applying them only at the project level creates gaps and inconsistent compliance. Option B is wrong because a flat project structure with no folders prevents hierarchical policy inheritance and scalable governance. Option E is wrong because lumping all team projects into a single 'Teams' folder without further grouping removes the per-team and per-environment separation needed for least-privilege IAM and policy scoping.

Answer

Use organization policies at the project level only to enforce compliance.

Answer

Create a flat project structure under the organization node with no folders.

Answer

Place all team projects in a single folder named 'Teams' without further grouping.

Question 9

Your team is using Cloud Monitoring dashboards to monitor a multi-service architecture. You want to manage dashboards as code using Terraform. Which approach should you use to create a dashboard?

Accepted Answer

Use the google_monitoring_dashboard Terraform resource with a dashboard JSON configuration. The google_monitoring_dashboard Terraform resource accepts a dashboard_json field containing the Cloud Monitoring dashboard definition, allowing dashboards to be managed declaratively as code. This is the supported, first-class Terraform approach for Cloud Monitoring dashboards. It integrates with Terraform state, plan/apply, and version control without custom tooling.

Answer

Use the Monitoring API directly from Terraform with a custom provider

Answer

Create the dashboard manually and export it as a JSON file, then import into Terraform

Answer

Use gcloud alpha monitoring dashboards create command with a YAML file

Question 10

During an incident, an SRE team uses an incident command system. Which role is responsible for coordinating communication and resources, but not for technical debugging?

Accepted Answer

Incident Commander. In an incident command system (ICS), the Incident Commander owns overall coordination, resource allocation, and communication with stakeholders — but deliberately does not dive into technical debugging. That separation lets the IC maintain situational awareness and keep the response organized while subject-matter experts handle the technical work.

Answer

Subject Matter Expert

Answer

Operations Lead

Answer

Scribe