PCDE Practice Test — Free Google Professional Cloud Database Engineer Questions with Explanations

A retail company is deploying a new Cloud SQL for MySQL instance for an order management system. The database must survive a zonal failure with minimal downtime and no data loss for committed transactions. They want the simplest configuration that meets this requirement. What should they do?

A financial application requires zero data loss (RPO=0) and automatic failover within 60 seconds in the event of a zone failure. The database must support ACID transactions. Which Google Cloud service meets these requirements?

An organization is migrating an Oracle database to Cloud SQL for PostgreSQL. They have numerous stored procedures written in PL/SQL. Which tool should they use to automatically convert these procedures to PL/pgSQL?

An organization is migrating an Oracle database to PostgreSQL on Compute Engine. They used Ora2Pg to migrate schema and data. After migration, they want to validate that stored procedures produce correct results. Which tool should they use for unit testing the migrated PL/pgSQL code?

A company is planning to use Cloud Spanner for a new global application. They estimate a peak write throughput of 10,000 mutations per second. What is the minimum number of processing units (PUs) required, given that each PU supports up to 2000 mutations/second?

An engineer is migrating a workload from a relational database to Bigtable. The current schema has a Customers table (1M rows) and an Orders table (100M rows) with a foreign key. Queries often fetch all orders for a customer. What is the best row key design for the Bigtable orders table?

A company is migrating a large on-premise Hadoop workload to Google Cloud. The data is stored in HBase and consists of time-series logs with 10 PB of data. They need a fully managed NoSQL solution with high throughput and low latency. Which migration path should they choose?

An engineer needs to restore a Cloud Spanner database from a backup that was taken 2 hours ago. The backup is stored in Cloud Storage. What steps are required?

A company is using Cloud SQL for PostgreSQL and needs to perform point-in-time recovery (PITR) to recover from a logical error that occurred 30 minutes ago. They have already configured automated backups. What additional configuration is required?

Your company runs a critical application on Google Kubernetes Engine (GKE) with a StatefulSet using persistent volumes backed by Compute Engine persistent disks. The application performs frequent small random writes to a MySQL database stored on the persistent disks. You notice that the disk write latency has increased significantly, and the application's throughput has dropped. Monitoring shows that the disk queue depth is consistently high. The current disk type is pd-standard. What is the most cost-effective way to reduce write latency and improve throughput?

You administer a Cloud SQL for PostgreSQL instance running with 4 vCPUs and 15 GB of memory. The application frequently runs complex read-only reporting queries during business hours. Recently, the database started throwing 'out of memory' errors, and the instance's memory usage is consistently above 90%. You have enabled the pgtune recommendations and applied them. The workload is read-heavy and does not require a high write throughput. Which change would most effectively reduce memory pressure while maintaining query performance?

Your team needs to add a new non-nullable column with a default value to a large Cloud Spanner table. The table has thousands of simultaneous writes per second. Which approach minimizes downtime and resource usage?

A company is setting up access control for a BigQuery dataset using the above IAM policy. An analyst who is a member of the group 'analysts@example.com' also has the user account 'analyst@example.com'. They need to create new tables in the dataset. What will be the outcome?

A financial services company uses Cloud Spanner for a global ledger application. The 'Transactions' table has a primary key of 'TransactionId' (a UUID string) and includes columns 'AccountId', 'Amount', and 'Timestamp'. The application frequently runs queries that retrieve all transactions for a specific account within a date range, sorted by timestamp. These queries are currently slow because they require a full table scan. The team wants to optimize the schema for these queries without changing the application's write pattern, which inserts transactions with random UUIDs. What should they do?

Refer to the exhibit. A BI query is performing slowly. The query plan shows a large shuffle in the aggregate stage. The table is not partitioned or clustered. Which optimization would most directly reduce the shuffle size?

A BI team uses BigQuery to report on customer orders. The 'customers' dimension table is updated nightly with Type 2 Slowly Changing Dimensions (SCD). However, some reports show incorrect historical aggregates because the fact table references only the current customer key. Which approach resolves this issue?

A team is adopting GitOps for infrastructure. They want to ensure that all Terraform configuration changes are automatically applied after merging to the main branch. Which CI/CD approach best supports this?

A team uses Helm charts to deploy applications to GKE. They need to manage environment-specific configurations (e.g., dev, staging, prod) using a single chart. Which tool should they use?

A company is designing a database schema for a global e-commerce platform. Orders are created with high frequency, and order status updates occur frequently. The team needs to choose a primary key strategy for the orders table in Spanner. Which approach minimizes hot-spotting?

A BI dashboard query is slow and high cost. The query does multiple joins on large tables and uses window functions. The data engineer suggests using materialized views. However, the query uses non-deterministic functions. What is the limitation?