PCD Deploy Scalable and Highly Available Databases in Google Cloud Practice Test 2 — 15 Questions

Question 1

A company is migrating a PostgreSQL application to Cloud SQL. They require automatic failover in under 60 seconds if the primary instance fails, and they want to minimize write latency. Which configuration should they choose?

Accepted Answer

Create a Cloud SQL for PostgreSQL instance with high availability (HA) configuration.. Cloud SQL HA uses a synchronous standby in a different zone within the same region, providing automatic failover in under 60 seconds and no data loss. Cross-region replicas are asynchronous and do not meet the failover time requirement. Zonal instances lack HA. Regional clusters are for Spanner.

Answer

Create a zonal Cloud SQL instance and set up a read replica in a different zone.

Answer

Create a Cloud SQL for PostgreSQL instance with cross-region replication.

Answer

Configure a Cloud Spanner regional instance with multi-zone nodes.

Question 2

A financial services company needs a globally distributed, strongly consistent database that can handle OLTP workloads with high throughput and automatic scaling. Which Google Cloud database should they use?

Accepted Answer

Cloud Spanner. Cloud Spanner is the only Google Cloud database that provides global distribution with strong consistency and horizontal scaling for OLTP workloads. Bigtable is eventually consistent across regions. Cloud SQL is regional. Firestore is eventually consistent and limited to single-region or limited multi-region.

Answer

Firestore

Answer

Cloud SQL

Answer

Cloud Bigtable

Question 3

An engineering team is designing an AlloyDB cluster for an e-commerce platform. They anticipate variable read traffic and want to automatically add or remove read-only compute capacity based on CPU utilization. Which feature should they enable?

Accepted Answer

Read pool autoscaling. AlloyDB’s read pool autoscaling automatically adjusts the number of read pool instances based on metrics like CPU utilization. Query distribution is built-in, but autoscaling is the specific feature for capacity changes. Instance groups are a Compute Engine concept. Read replicas in Cloud SQL are not automatically scaled.

Answer

Enable query distribution across read pool instances.

Answer

Configure a managed instance group for the read pool.

Answer

Set up Cloud SQL read replicas with cross-region replication.

Question 4

A developer needs to connect a Cloud SQL MySQL instance from an application running on Compute Engine without whitelisting IP addresses. Which method should they use?

Accepted Answer

Configure the application to use Cloud SQL Auth Proxy.. Cloud SQL Auth Proxy provides secure access using IAM permissions, avoiding the need to whitelist IP addresses. SSL without proxy still requires IP allowlisting. Private IP requires VPC peering and is not automatically connected. Cloud Shell is not for application connectivity.

Answer

Connect via Cloud Shell using the mysql client.

Answer

Set up a Cloud SQL private IP connection.

Answer

Use SSL/TLS connection with the public IP address.

Question 5

A company uses Cloud Bigtable for time-series data. They notice uneven load distribution across nodes causing hot spots. Which tool should they use to identify the hot spots?

Accepted Answer

Cloud Bigtable Key Visualiser. Cloud Bigtable Key Visualiser graphically shows read/write heatmaps to identify hot spots. Monitoring dashboards show metrics but not specific hot spots. cbt tool is CLI, not visual. Cloud Logging records operations but doesn't visualize load distribution.

Answer

Cloud Monitoring dashboards

Answer

cbt command-line tool

Answer

Cloud Logging

Question 6

A company needs to run AlloyDB on-premises to maintain data sovereignty while leveraging the same management APIs as in Google Cloud. Which AlloyDB offering should they use?

Accepted Answer

AlloyDB Omni. AlloyDB Omni is designed for on-premises deployment with the same AlloyDB engine, managed via Google Cloud’s APIs or CLI. AlloyDB clusters are cloud-only. Cloud SQL is a different service. Bigtable Omni is for Bigtable, not AlloyDB.

Answer

Cloud SQL for PostgreSQL with HA

Answer

Bigtable Omni

Answer

AlloyDB cluster with cross-region replication

Question 7

A Cloud Spanner instance is configured with 1000 processing units. The workload has unpredictable traffic spikes. To ensure consistent performance, the team wants to automatically adjust capacity based on a high-priority CPU target of 60%. What should they configure?

Accepted Answer

Set up Cloud Spanner autoscaling with min=500, max=2000 processing units and high-priority CPU target=0.6.. Cloud Spanner’s autoscaler can automatically adjust processing units based on CPU utilization. Setting min and max processing units with a high-priority CPU target enables autoscaling. Node count is older, processing units are granular. Compute capacity is not the same as autoscaling. Bigtable autoscaler is for Bigtable.

Answer

Configure compute capacity with a fixed number of nodes.

Answer

Enable Bigtable autoscaling for the Spanner instance.

Answer

Manually adjust nodes when CPU exceeds 60%.

Question 8

A startup wants to use Firestore for a mobile app. They need to restrict access so that users can only read and write their own data. Which Firestore security rule feature should they use?

Accepted Answer

Use request.auth to get the user's UID and compare it to the document's owner field.. Firestore security rules use `request.auth` to identify the authenticated user and `resource.data` to access document fields. Combining these allows rules to compare the user ID in the request with the document’s owner field. `get()` and `exists()` are functions for cross-document validation, not for user identity.

Answer

Use Firebase Authentication and enable anonymous sign-in.

Answer

Set up IAM roles for each user.

Answer

Use the get() function to retrieve the user's document each time.

Question 9

A company is using Cloud SQL for PostgreSQL and wants to ensure that all connections to the database use SSL/TLS. They have set the `require_ssl` flag but still see some connections using non-SSL. What is the most likely reason?

Accepted Answer

Existing connections that were established before the flag was enabled are still active.. The `require_ssl` flag only affects new connections; existing connections may continue without SSL until they are re-established. Restarting the instance forces all connections to reconnect with SSL. The flag does not require clients to connect via Auth Proxy. Old clients may not support SSL but the flag would block them, not allow non-SSL.

Answer

The application is using a database driver that does not support SSL.

Answer

The flag only applies to connections using the Cloud SQL Auth Proxy.

Answer

The flag must be configured in the database server parameters, not the Cloud SQL admin panel.

Question 10

A manufacturing company collects sensor data from thousands of devices. They need a database that can handle a write throughput of 100,000 rows per second and read latency under 10ms. Data is keyed by device ID and timestamp. Which Google Cloud database should they choose?

Accepted Answer

Cloud Bigtable. Cloud Bigtable is designed for high-throughput writes and low-latency reads for time-series data. It can handle 100k rows/sec with appropriate node count. Cloud Spanner has lower write throughput per dollar. Cloud SQL is not designed for such high write throughput. Firestore has limits on write throughput per collection.

Answer

Cloud Spanner

Answer

Cloud SQL

Answer

Firestore

Question 11

A company needs a database for an e-commerce application that requires strong consistency and the ability to scale horizontally across multiple regions. They expect high write throughput and need to support SQL queries. Which database should they choose?

Accepted Answer

Cloud Spanner. Cloud Spanner is a globally distributed, strongly consistent relational database that scales horizontally and supports SQL. Bigtable is NoSQL and eventually consistent. Cloud SQL is regional and does not scale horizontally. Firestore is NoSQL and eventually consistent across regions.

Answer

Cloud Bigtable

Answer

Cloud SQL

Answer

Firestore

Question 12

An engineer needs to create a Cloud SQL instance for a development environment with minimal cost. The instance will have low traffic, and storage growth is expected to be gradual. Which storage configuration should they choose?

Accepted Answer

Use SSD storage with storage auto-increase enabled.. SSD storage is recommended for most workloads due to performance, and enabling auto-increase ensures you don't run out of disk. HDD is cheaper but has much lower IOPS, which may cause performance issues even for dev. Disabling auto-increase risks downtime. The smallest disk size with SSD and auto-increase is cost-effective.

Answer

Use HDD storage with storage auto-increase disabled.

Answer

Use SSD storage with storage auto-increase disabled.

Answer

Use HDD storage with storage auto-increase enabled.

Question 13

A company has a Cloud SQL for MySQL instance in the us-central1 region. They want to improve read performance for a report generation tool that runs in us-west1, and also provide disaster recovery in case the primary fails. Which TWO actions should they take?

Accepted Answer

Configure the report generation tool to connect to the cross-region replica.. Cross-region read replicas serve both read scaling in another region and disaster recovery. A regional HA instance only provides HA within the same region. Increasing machine type improves performance but not DR. Creating a read replica in the same region does not help with cross-region DR.

Answer

Enable high availability (HA) on the primary instance.

Answer

Change the primary instance to a larger machine type.

Answer

Add a read replica in us-central1.

Question 14

A company is deploying a Cloud Spanner database for a global application. They need to minimize write latency for users in North America and Europe while ensuring strong consistency. They also want to control costs by only paying for the capacity they use. Which THREE features should they use?

Accepted Answer

Enable autoscaling with processing units.. A multi-region configuration spans North America and Europe, reducing write latency for those users. Autoscaling adjusts capacity based on demand, controlling costs. Dual-region is limited to two regions within one continent. Processing units are the granular capacity unit for autoscaling. Nodes are fixed capacity.

Answer

Dual-region instance configuration.

Answer

Use a fixed number of nodes to simplify management.

Answer

Set up a read replica in each continent.

Question 15

A company is using Cloud Bigtable for real-time analytics. They want to ensure high availability and the ability to perform maintenance without downtime. They also want to reduce read latency for users in Asia. Which TWO actions should they take?

Accepted Answer

Add a secondary cluster in an Asian region.. Adding a secondary cluster in an Asian region provides regional redundancy (HA) and reduces read latency for Asian users. Application profile routing sends reads to the nearest cluster. Adding nodes to the existing cluster improves throughput but not HA or latency in Asia. HDD storage is slower. Multi-region is not a Bigtable concept.

Answer

Switch to HDD storage to reduce costs.

Answer

Increase the number of nodes in the existing cluster.

Answer

Convert to a multi-region instance.