PCDE Matching — 10 Questions

Question 1

Match each Cloud SQL tier to its description.

Accepted Answer

db-f1-micro: 0.5 vCPU, 0.6 GB memory. Cloud SQL tiers are defined by vCPU and memory. Common confusions arise when swapping memory-heavy and compute-heavy tiers, or mixing vCPU counts. Ensure you match the exact specifications for each tier.

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db-n1-highmem-2: 2 vCPU, 3.75 GB memory

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db-n1-highcpu-2: 0.5 vCPU, 0.6 GB memory

Question 2

Match each Cloud SQL backup type to its retention policy.

Accepted Answer

Automated backups: Retained for a user-specified number of days (default 7). Cloud SQL backup types: Automated backups have configurable retention (default 7 days). On-demand backups are retained until deleted (max 365 days). Point-in-time recovery logs are kept for the same period as automated backup retention. Common confusions involve swapping these policies.

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Automated backups: Retained until deleted

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On-demand backups: Retained for 7 days by default

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Point-in-time recovery logs: Retained for 365 days regardless of backup retention

Question 3

Match each Cloud Spanner replication type to its purpose.

Accepted Answer

Read-write replica: Can serve reads and writes and participates in voting.. Cloud Spanner supports read-write, read-only, and witness replicas. Read-write replicas handle all operations and vote; read-only replicas scale reads without voting; witness replicas provide quorum without storing data. Common confusions include swapping the roles of read-only and witness replicas.

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Read-write replica: Serves reads only and does not vote.

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Read-only replica: Does not store data but participates in voting.

Question 4

Match each Cloud Spanner concept to its definition.

Accepted Answer

TrueTime: A globally distributed clock service that provides tightly synchronized timestamps.. These are key concepts for understanding Spanner's architecture and consistency.

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TrueTime: A service that provides eventual consistency through local clocks.

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External Consistency: Guarantees that all replicas eventually agree on a total order of transactions.

Question 5

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.

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Firestore: Horizontally scalable relational database for global transactions

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Memorystore: Relational database for standard workloads

Question 6

Match each database migration term to its description.

Accepted Answer

Homogeneous migration: Migrating a database from one source engine to the same target engine.. The correct matches are: Homogeneous migration = same engine, Heterogeneous migration = different engine, Database Migration Service = Google Cloud's database migration tool. Common confusions involve swapping the definitions of homogeneous and heterogeneous, or misattributing DMS to application migration.

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Homogeneous migration: Migrating a database to a different database engine.

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Heterogeneous migration: Migrating a database to the same database engine.

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Database Migration Service (DMS): A tool for migrating applications to compute engines.

Question 7

Match each BigQuery DDL statement to its function.

Accepted Answer

CREATE TABLE: Creates a new table in a dataset. BigQuery DDL statements manage database objects. CREATE TABLE and CREATE VIEW define new objects, while DROP TABLE removes them. Common confusions arise from swapping CREATE and DROP or using ALTER for creation.

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CREATE TABLE: Deletes a table and its data

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ALTER TABLE: Creates a new table in a dataset

Question 8

Match each Cloud SQL high-availability feature to its description.

Accepted Answer

Automatic failover: Automatically switches to a standby instance in a different zone if the primary instance fails, ensuring minimal downtime.. Automatic failover switches to a standby zone on failure, read replicas provide read-only copies for scaling, and point-in-time recovery allows restoring to any time within retention. Common confusions mix automatic failover with read replicas.

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Automatic failover: Provides read-only copies of the primary instance to distribute read load.

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Read replicas: Automatically switches to a standby instance in a different zone if the primary fails.

Question 9

Match each BigQuery feature to its purpose.

Accepted Answer

Partitioning: Divides table into segments based on a column (e.g., date) to reduce query cost and improve performance.. These features optimize cost, performance, and management in BigQuery. Partitioning reduces scan costs, Clustering improves query performance, Materialized Views accelerate complex queries, and Slots provide resource control.

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Partitioning: Sorts data based on one or more columns to improve query performance.

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Clustering: Divides table into segments based on a column to reduce cost.

Question 10

Match each Google Cloud tool to its purpose in database management.

Accepted Answer

Cloud SQL: Managed relational database service for MySQL, PostgreSQL, SQL Server. Cloud SQL, Cloud Spanner, and BigQuery are core Google Cloud database tools. Cloud SQL is for managed relational databases, Cloud Spanner for globally distributed relational databases, and BigQuery for analytics. Distractors confuse Cloud SQL with NoSQL services and Cloud Spanner with caching services.

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Cloud SQL: Fully managed NoSQL database for real-time data

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Cloud Spanner: In-memory data store for caching