PDE Storing the Data Practice Test 6 — 15 Questions

Question 1

A company needs to store petabytes of time-series IoT sensor data and query it with single-digit millisecond latency at millions of reads per second. The data has a simple key-value structure with timestamps. Which Google Cloud database is MOST appropriate?

Accepted Answer

Cloud Bigtable. Cloud Bigtable is the correct choice because it is a fully managed, scalable NoSQL database designed for large analytical and operational workloads, offering consistent sub-10ms latency for high-throughput reads and writes. It natively supports time-series data with row key design optimized for timestamp-based queries, and can handle millions of reads per second across petabytes of data, making it ideal for IoT sensor data.

Answer

BigQuery

Answer

Firestore

Answer

Cloud Spanner

Question 2

You are designing a Cloud Storage bucket to hold sensitive financial documents that must not be deleted or overwritten for 7 years. After the retention period, the documents can be deleted automatically. Which configuration should you use?

Accepted Answer

Use Bucket Lock with a retention policy of 7 years and configure a lifecycle rule to delete objects after 7 years.. Option D is correct because Bucket Lock (also known as Object Lock) provides a WORM (Write Once, Read Many) retention policy that prevents objects from being deleted or overwritten for a specified period. By setting a retention policy of 7 years, you enforce the required compliance hold. Then, a lifecycle rule configured to delete objects after 7 years ensures automatic removal once the retention period expires. This combination meets both the retention and automatic deletion requirements.

Answer

Set a retention policy on the bucket for 7 years and enable Object Versioning.

Answer

Use Object Lock with WORM mode and set a retention period of 7 years. After the period, objects are automatically deleted.

Answer

Set a lifecycle rule to delete objects after 7 years and enable Bucket Lock.

Question 3

Which Google Cloud service is a fully managed relational database for MySQL, PostgreSQL, and SQL Server, offering automatic replication and backups?

Accepted Answer

Cloud SQL. Cloud SQL is the correct answer because it is Google Cloud's fully managed relational database service that supports MySQL, PostgreSQL, and SQL Server. It provides automatic replication across zones and automated backups, making it the ideal choice for traditional relational database workloads without the need for manual administration.

Answer

Cloud Spanner

Answer

AlloyDB

Answer

Bigtable

Question 4

A company uses Cloud Storage as a data lake with raw, curated, and processed zones. Data in the raw zone should be automatically moved to a cheaper storage class after 30 days, and deleted after 1 year. What is the most efficient way to implement this?

Accepted Answer

Use Object Lifecycle Management with rules to transition to Coldline after 30 days and delete after 365 days.. Object Lifecycle Management in Cloud Storage allows you to set rules based on object age. You can transition objects to a lower-cost storage class (e.g., Nearline or Coldline) after 30 days and delete after 365 days.

Answer

Write a Cloud Function that runs daily, checks object ages, and moves/deletes them.

Answer

Use Cloud Scheduler to run a script that changes storage class and deletes objects.

Answer

Set a retention policy on the raw zone to prevent deletion and manually clean up.

Question 5

You are designing a row key for Cloud Bigtable to store user activity logs. Each log entry has a timestamp (millisecond precision) and a user ID. There will be millions of writes per second from many users. To avoid hotspotting, which row key design is BEST?

Accepted Answer

hash(userID)#userID#timestamp_millis. Option D is best because it uses a hash of the user ID as the row key prefix, which distributes writes across all Bigtable nodes and avoids hotspotting. Appending the user ID and timestamp ensures uniqueness and supports efficient queries for a specific user's logs. This design prevents the sequential timestamp from creating a single hot node, which is critical for handling millions of writes per second.

Answer

timestamp_millis#hash(userID)

Answer

timestamp_millis#userID

Answer

userID#timestamp_millis

Question 6

Which Google Cloud service is a serverless, highly scalable data warehouse for analytical queries, supporting SQL and integration with BI tools?

Accepted Answer

BigQuery. BigQuery is a serverless, highly scalable data warehouse designed for analytical queries over large datasets. It supports standard SQL and integrates seamlessly with BI tools like Looker and Tableau, making it the correct choice for this use case.

Answer

Firestore

Answer

Cloud SQL

Answer

Cloud Spanner

Question 7

A company wants to run hybrid transactional and analytical workloads on a PostgreSQL-compatible database with high performance. Which service should they choose?

Accepted Answer

AlloyDB. AlloyDB is the correct choice because it is a fully managed PostgreSQL-compatible database service specifically designed for high-performance hybrid transactional and analytical workloads. It combines transactional processing with built-in columnar analytics, delivering up to 4x faster transactional performance and up to 100x faster analytical queries than standard PostgreSQL, without requiring any schema changes or ETL.

Answer

Cloud Spanner

Answer

Cloud SQL for PostgreSQL

Answer

BigQuery

Question 8

You need to store and query a large dataset of customer profiles. The data is semi-structured and frequently updated. The application requires offline support for mobile users. Which database is MOST appropriate?

Accepted Answer

Firestore. Firestore is the most appropriate choice because it is a NoSQL document database designed for semi-structured data, real-time synchronization, and offline support. It provides built-in offline persistence for mobile clients, allowing users to read and write data even without network connectivity, and automatically syncs changes when the connection is restored. This directly meets the requirements of semi-structured data, frequent updates, and offline mobile support.

Answer

BigQuery

Answer

Cloud Bigtable

Answer

Cloud SQL

Question 9

A company is using BigQuery for analytics and needs to ensure that certain columns containing PII are encrypted with a customer-managed key (CMEK). Which approach should they take?

Accepted Answer

Use BigQuery column-level encryption with AEAD functions and a Cloud KMS key.. Option B is correct because BigQuery column-level encryption using AEAD (Authenticated Encryption with Associated Data) functions allows you to encrypt specific columns containing PII with a customer-managed key (CMEK) stored in Cloud KMS. This approach provides granular, field-level encryption that meets compliance requirements without affecting the rest of the table or dataset, and the encryption/decryption is performed transparently within BigQuery using the AEAD.DECRYPT_STRING function.

Answer

Use Cloud Data Loss Prevention (DLP) to mask the columns during query.

Answer

Apply CMEK at the dataset level; all tables inherit the encryption.

Answer

Store the data encrypted in Cloud Storage and use external tables with a CMEK.

Question 10

Which Google Cloud database offers global distribution, strong consistency, and a 99.999% SLA?

Accepted Answer

Cloud Spanner. Cloud Spanner is the only Google Cloud database that provides global distribution (horizontally scaling across regions), strong consistency (external consistency with TrueTime), and a 99.999% SLA. It combines the benefits of relational database structure with non-relational horizontal scale, making it ideal for globally distributed, strongly consistent workloads.

Answer

Cloud Bigtable

Answer

Firestore

Answer

Cloud SQL

Question 11

You need to create a Cloud Storage bucket for a data lake that will store raw ingested data. The data must be immutable and cannot be deleted or overwritten for a compliance period of 5 years. Which feature should you enable?

Accepted Answer

Bucket Lock with a retention policy of 5 years. Bucket Lock with a retention policy enforces a minimum retention period on all objects in the bucket. During the retention period, objects cannot be deleted or overwritten. This is exactly for compliance needs.

Answer

Object Versioning

Answer

Lifecycle rules to delete objects after 5 years

Answer

Object Lock with governance mode

Question 12

A team needs to run analytics on data stored in Cloud Storage (Parquet format) without moving it into BigQuery storage. They want to use SQL queries and BigQuery features like caching and partitioning. Which approach should they use?

Accepted Answer

Create a BigQuery external table pointing to the Cloud Storage location.. Option A is correct because an external table in BigQuery allows you to query data stored in Cloud Storage (Parquet format) using standard SQL without moving the data into BigQuery's managed storage. This approach supports BigQuery features like caching (results caching) and partitioning (by defining a Hive-partitioned external table), meeting all requirements.

Answer

Use Cloud Dataproc to run Spark SQL on the data.

Answer

Load the data into BigQuery tables using a batch load job.

Answer

Use BigLake tables with Cloud Storage.

Question 13

A company is building a data lake on Cloud Storage. They need to organise data into zones for raw, curated, and processed layers. Which TWO practices should they follow? (Choose 2.)

Accepted Answer

Use separate Cloud Storage buckets for each zone (raw, curated, processed).. A data lake typically uses separate buckets or prefixes for raw (immutable), curated (cleaned/transformed), and processed (aggregated/reporting) data. Using prefixes within a single bucket is common, but separate buckets provide better isolation. Lifecycle rules can be applied per prefix or bucket.

Answer

Use the same storage class for all zones to simplify management.

Answer

Set retention policies on the raw zone to make data immutable.

Answer

Enable object versioning on all buckets to prevent data loss.

Question 14

You are designing a Cloud Spanner schema for a global e-commerce application. The database will include a Customers table and an Orders table. To optimise performance for queries that join Customers with their Orders, which THREE design choices are recommended? (Choose 3.)

Accepted Answer

Use interleaved tables: make Orders an interleaved table under Customers.. Spanner interleaved tables store child rows physically close to parent rows, improving join performance. Including the parent's primary key as the first part of the child's primary key is required for interleaving. Secondary indexes on non-key columns are also needed for efficient lookups.

Answer

Use a single table for both Customers and Orders and filter by CustomerId.

Answer

Denormalise the schema by embedding order details into the Customers table as repeated fields.

Question 15

A company wants to use BigQuery for analytics. They need to meet compliance requirements by encrypting data at rest with a key they control. Which TWO actions should they take? (Choose 2.)

Accepted Answer

Set the Cloud KMS key as the default encryption key for the BigQuery dataset.. BigQuery supports Customer-Managed Encryption Keys (CMEK) for encrypting data at rest. You need to create a Cloud KMS key and then set it as the default encryption key for a BigQuery dataset. All tables in that dataset will be encrypted with that key.

Answer

Create a Cloud Storage bucket and load data there.

Answer

Use VPC Service Controls to restrict access to the dataset.

Answer

Enable BigQuery column-level encryption using AEAD functions.