PCDBE practice questions 71–80

1. Question 71 · 170 in bank

   You are designing a highly available (HA) Cloud SQL for PostgreSQL instance that will be used by 100 databases. Each database contains 80 tables that were migrated from your on-premises environment to Google Cloud. The applications that use these databases are located in multiple regions in the US, and you need to ensure that read and write operations have low latency. What should you do?

   • ADeploy 2 Cloud SQL instances in the us-central1 region with HA enabled, and create read replicas in us-east1 and us-west1.
   • BDeploy 2 Cloud SQL instances in the us-central1 region, and create read replicas in us-east1 and us-west1.
   • CDeploy 4 Cloud SQL instances in the us-central1 region with HA enabled, and create read replicas in us-central1, us-east1, and us-west1.
   • DDeploy 4 Cloud SQL instances in the us-central1 region, and create read replicas in us-central1, us-east1 and us-west1.

   Show answer

   Answer: A

   Explanation

   A. B and D do not mention HA, so eliminate those. That leaves A and C. C talks about 4 instances with HA which presumably means 2 primaries each with an HA standby. Oddly, there are 4 zones in us-central1. The killer is having a read replica also in us-central1 which would mean the same zone would have a read replica and either a primary or HA standby. Not a good idea. Option A is the best choice. A primary and an HA standby in us-central1 (different zones) and then read replicas in us-east1 and us-west1.

   Source: Adapted from community discussion — dynamic_dba

   References

   • Google Cloud documentation

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2. Question 72 · 170 in bank

   You work in the logistics department. Your data analysis team needs daily extracts from Cloud SQL for MySQL to train a machine learning model. The model will be used to optimize next-day routes. You need to export the data in CSV format. You want to follow Google-recommended practices. What should you do?

   • AUse Cloud Scheduler to trigger a Cloud Function that will run a select * from table(s) query to call the cloudsql.instances.export API.
   • BUse Cloud Scheduler to trigger a Cloud Function through Pub/Sub to call the cloudsql.instances.export API.
   • CUse Cloud Composer to orchestrate an export by calling the cloudsql.instances.export API.
   • DUse Cloud Composer to execute a select * from table(s) query and export results.

   Show answer

   Answer: B

   Explanation

   As noted in text from this link, Cloud Function can be triggered with/without pub/sub. I think distinction between A & B is suggestion in A the API s called from query, which is not correct - the 'select query' is passed as parameter in call, so I think B is correct. "Note that we could also have a Pub/Sub Trigger configured Cloud Function get triggered by the Scheduler by using the same steps given above to create a job. Except that in the target, you will select Pub/Sub and provide the Pub/Sub Topic name. At the scheduler trigger time, the Cloud Scheduler will publish a message to the topic with the message body that you specify." https://rominirani.com/google-cloud-functions-tutorial-using-the-cloud-scheduler-to-trigger-your-functions-756160a95c43

   Source: Adapted from community discussion — sp57

   References

   • Google Cloud documentation
   • Google Cloud documentation

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3. Question 73 · 170 in bank

   You are choosing a database backend for a new application. The application will ingest data points from IoT sensors. You need to ensure that the application can scale up to millions of requests per second with sub-10ms latency and store up to 100 TB of history. What should you do?

   • AUse Cloud SQL with read replicas for throughput.
   • BUse Firestore, and rely on automatic serverless scaling.
   • CUse Memorystore for Memcached, and add nodes as necessary to achieve the required throughput.
   • DUse Bigtable, and add nodes as necessary to achieve the required throughput.

   Show answer

   Answer: D

   Explanation

   D. Simply a classic use case for Bigtable. Neither Cloud SQL, Firestore nor Memorystore have either the capacity or latency to provide the solution.

   Source: Adapted from community discussion — dynamic_dba

   References

   • Google Cloud documentation

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4. Question 74 · 170 in bank

   You are designing a payments processing application on Google Cloud. The application must continue to serve requests and avoid any user disruption if a regional failure occurs. You need to use AES-256 to encrypt data in the database, and you want to control where you store the encryption key. What should you do?

   • AUse Cloud Spanner with a customer-managed encryption key (CMEK).
   • BUse Cloud Spanner with default encryption.
   • CUse Cloud SQL with a customer-managed encryption key (CMEK).
   • DUse Bigtable with default encryption.

   Show answer

   Answer: A

   Explanation

   A. Avoiding user disruption if a regional failure occurs means you need to pick a multi-region service. That rules out C and D. Having more control over the EKs means CMEK. That eliminates B.

   Source: Adapted from community discussion — dynamic_dba

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5. Question 75 · 170 in bank

   You are managing a Cloud SQL for MySQL environment in Google Cloud. You have deployed a primary instance in Zone A and a read replica instance in Zone B, both in the same region. You are notified that the replica instance in Zone B was unavailable for 10 minutes. You need to ensure that the read replica instance is still working. What should you do?

   • AUse the Google Cloud Console or gcloud CLI to manually create a new clone database.
   • BUse the Google Cloud Console or gcloud CLI to manually create a new failover replica from backup.
   • CVerify that the new replica is created automatically.
   • DStart the original primary instance and resume replication.

   Show answer

   Answer: C

   Explanation

   C Recovery Process: Once Zone-B becomes available again, Cloud SQL will initiate the recovery process for the impacted read replica. The recovery process involves the following steps: 1. Synchronization: Cloud SQL will compare the data in the recovered read replica with the primary instance in Zone-A. If there is any data divergence due to the unavailability period, Cloud SQL will synchronize the read replica with the primary instance to ensure data consistency. 2. Catch-up Replication: The recovered read replica will start catching up on the changes that occurred on the primary instance during its unavailability. It will apply the necessary updates from the primary instance's binary logs (binlogs) to bring the replica up to date. 3. Resuming Read Traffic: Once the synchronization and catch-up replication processes are complete, the read replica in Zone-B will resume its normal operation. It will be able to serve read traffic and stay updated with subsequent changes from the primary instance.

   Source: Adapted from community discussion — Sandipcst

   References

   • Google Cloud documentation

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6. Question 76 · 170 in bank

   You are migrating an on-premises application to Google Cloud. The application requires a high availability (HA) PostgreSQL database to support business-critical functions. Your company's disaster recovery strategy requires a recovery time objective (RTO) and recovery point objective (RPO) within 30 minutes of failure. You plan to use a Google Cloud managed service. What should you do to maximize uptime for your application?

   • ADeploy Cloud SQL for PostgreSQL in a regional configuration. Create a read replica in a different zone in the same region and a read replica in another region for disaster recovery.
   • BDeploy Cloud SQL for PostgreSQL in a regional configuration with HA enabled. Take periodic backups, and use this backup to restore to a new Cloud SQL for PostgreSQL instance in another region during a disaster recovery event.
   • CDeploy Cloud SQL for PostgreSQL in a regional configuration with HA enabled. Create a cross-region read replica, and promote the read replica as the primary node for disaster recovery.
   • DMigrate the PostgreSQL database to multi-regional Cloud Spanner so that a single region outage will not affect your application. Update the schema to support Cloud Spanner data types, and refactor the application.

   Show answer

   Answer: C

   Explanation

   C. D might be possible but it’s a lot of effort to migrate to a different platform. Eliminate D. A does not mention HA. Eliminate A. B says to take periodic backups which doesn’t support an RTO/RPO of 30 minutes. The best answer is deploy an HA configuration and have a read replica you could promote to the primary in a different region. C is the best answer.

   Source: Adapted from community discussion — dynamic_dba

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7. Question 77 · 170 in bank

   Your company has PostgreSQL databases on-premises and on Amazon Web Services (AWS). You are planning multiple database migrations to Cloud SQL in an effort to reduce costs and downtime. You want to follow Google-recommended practices and use Google native data migration tools. You also want to closely monitor the migrations as part of the cutover strategy. What should you do?

   • AUse Database Migration Service to migrate all databases to Cloud SQL.
   • BUse Database Migration Service for one-time migrations, and use third-party or partner tools for change data capture (CDC) style migrations.
   • CUse data replication tools and CDC tools to enable migration.
   • DUse a combination of Database Migration Service and partner tools to support the data migration strategy.

   Show answer

   Answer: A

   Explanation

   A. The question says to use Google native data migration tools. That eliminates B and D. C doesn't specify the data replication tool in question so it's a reasonable assumption its referring to database native replication which wouldn't be a Google native solution. That eliminates C. That leave A.

   Source: Adapted from community discussion — dynamic_dba

   References

   • Google Cloud documentation
   • Google Cloud documentation

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8. Question 78 · 170 in bank

   Your team is running a Cloud SQL for MySQL instance with a 5 TB database that must be available 24/7. You need to save database backups on object storage with minimal operational overhead or risk to your production workloads. What should you do?

   • AUse Cloud SQL serverless exports.
   • BCreate a read replica, and then use the mysqldump utility to export each table.
   • CClone the Cloud SQL instance, and then use the mysqldump utlity to export the data.
   • DUse the mysqldump utility on the primary database instance to export the backup.

   Show answer

   Answer: A

   Explanation

   A. Minimal operational overhead eliminates B and C. Minimal risk to production workloads eliminates D. That leaves A. Least amount of work and doesn't impact the primary instance.

   Source: Adapted from community discussion — dynamic_dba

   References

   • Google Cloud documentation
   • Google Cloud documentation

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9. Question 79 · 170 in bank

   You are deploying a new Cloud SQL instance on Google Cloud using the Cloud SQL Auth proxy. You have identified snippets of application code that need to access the new Cloud SQL instance. The snippets reside and execute on an application server running on a Compute Engine machine. You want to follow Google-recommended practices to set up Identity and Access Management (IAM) as quickly and securely as possible. What should you do?

   • AFor each application code, set up a common shared user account.
   • BFor each application code, set up a dedicated user account.
   • CFor the application server, set up a service account.
   • DFor the application server, set up a common shared user account.

   Show answer

   Answer: C

   Explanation

   C. The Google recommendation would be for an application to use a service account. None of the other options make sense in light of this.

   Source: Adapted from community discussion — dynamic_dba

   References

   • Google Cloud documentation

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10. Question 80 · 170 in bank

    Your organization is running a low-latency reporting application on Microsoft SQL Server. In addition to the database engine, you are using SQL Server Analysis Services (SSAS), SQL Server Reporting Services (SSRS), and SQL Server Integration Services (SSIS) in your on-premises environment. You want to migrate your Microsoft SQL Server database instances to Google Cloud. You need to ensure minimal disruption to the existing architecture during migration. What should you do?

    • AMigrate to Cloud SQL for SQL Server.
    • BMigrate to Cloud SQL for PostgreSQL.
    • CMigrate to Compute Engine.
    • DMigrate to Google Kubernetes Engine (GKE).

    Show answer

    Answer: C

    Explanation

    I think they do this on purpose. They simply give a random answer on each question and let us fight in the comment section to find the truth answer. The good thing is that we have to work out ass to find the correct answer and we might learn something new along the way (or at least in my case) :D

    Source: Adapted from community discussion — absero1609

    References

    • Google Cloud documentation

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PCDBE practice, question 71. 170 questions available.