PCDBE practice questions 101–110

1. Question 101 · 170 in bank

   Your organization has a busy transactional Cloud SQL for MySQL instance. Your analytics team needs access to the data so they can build monthly sales reports. You need to provide data access to the analytics team without adversely affecting performance. What should you do?

   • ACreate a read replica of the database, provide the database IP address, username, and password to the analytics team, and grant read access to required tables to the team.
   • BCreate a read replica of the database, enable the cloudsql.iam_authentication flag on the replica, and grant read access to required tables to the analytics team.
   • CEnable the cloudsql.iam_authentication flag on the primary database instance, and grant read access to required tables to the analytics team.
   • DProvide the database IP address, username, and password of the primary database instance to the analytics, team, and grant read access to required tables to the team.

   Show answer

   Answer: B

   Explanation

   B because while both A and B work, B seems more native and secure since you aren't passing around database authentication passwords. You can also better manage the authentication through Google groups since you're using IAM.

   Source: Adapted from community discussion — juliorevk

   References

   • Google Cloud documentation
   • Google Cloud documentation
   • Google Cloud documentation
   • Google Cloud documentation
   • Google Cloud documentation

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2. Question 102 · 170 in bank

   Your organization stores marketing data such as customer preferences and purchase history on Bigtable. The consumers of this database are predominantly data analysts and operations users. You receive a service ticket from the database operations department citing poor database performance between 9 AM-10 AM every day. The application team has confirmed no latency from their logs. A new cohort of pilot users that is testing a dataset loaded from a third-party data provider is experiencing poor database performance. Other users are not affected. You need to troubleshoot the issue. What should you do?

   • AIsolate the data analysts and operations user groups to use different Bigtable instances.
   • BCheck the Cloud Monitoring table/bytes_used metric from Bigtable.
   • CUse Key Visualizer for Bigtable.
   • DAdd more nodes to the Bigtable cluster.

   Show answer

   Answer: C

   Explanation

   C. The test data set is likely to have poor row key design. When loaded into the database, that data is probably hitting the same node and causing a hot spot. Addng more nodes will not solve a hot spot. Eliminate D. Neither will creating a new instance (A). B might be of interest, but is not the primary tool to diagnose Bigtable performance problems. For that, use Key Visualizer. Best answer is C. https://cloud.google.com/bigtable/docs/keyvis-overview

   Source: Adapted from community discussion — dynamic_dba

   References

   • Google Cloud documentation
   • Google Cloud documentation
   • Google Cloud documentation

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3. Question 103 · 170 in bank

   Your company is developing a new global transactional application that must be ACID-compliant and have 99.999% availability. You are responsible for selecting the appropriate Google Cloud database to serve as a datastore for this new application. What should you do?

   • AUse Firestore.
   • BUse Cloud Spanner.
   • CUse Cloud SQL.
   • DUse Bigtable.

   Show answer

   Answer: B

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4. Question 104 · 170 in bank

   Select 2

   You want to migrate your PostgreSQL database from another cloud provider to Cloud SQL. You plan on using Database Migration Service and need to assess the impact of any known limitations. What should you do? (Choose two.)

   • AIdentify whether the database has over 512 tables.
   • BIdentify all tables that do not have a primary key.
   • CIdentity all tables that do not have at least one foreign key.
   • DIdentify whether the source database is encrypted using pgcrypto extension.
   • EIdentify whether the source database uses customer-managed encryption keys (CMEK).

   Show answer

   Answer: BE

   Explanation

   From this link (https://cloud.google.com/database-migration/docs/postgres/known-limitations), correct answers should be B and D. Excerpts supporting these choices: "For tables that don't have primary keys, Database Migration Service supports migration of the initial snapshot and INSERT statements during the change data capture (CDC) phase. You should migrate UPDATE and DELETE statements manually." "If encrypted databases require customer-managed encryption keys to decrypt the databases, and if Database Migration Service doesn't have access to the keys, then the databases can't be migrated. However, if customer data is encrypted by the pgcrypto extension, then the data can be migrated with Database Migration Service (because Cloud SQL supports the extension)." Therefore, for the migration to be executable: * Only tables with a primary key can be migrated; * Only data encrypted by the pgcrypto extension can be migrated.

   Source: Adapted from community discussion — examprof

   References

   • Google Cloud documentation

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5. Question 105 · 170 in bank

   Your organization is running a Firestore-backed Firebase app that serves the same top ten news stories on a daily basis to a large global audience. You want to optimize content delivery while decreasing cost and latency. What should you do?

   • AEnable serializable isolation in the Firebase app.
   • BDeploy a US multi-region Firestore location.
   • CBuild a Firestore bundle, and deploy bundles to Cloud CDN.
   • DCreate a Firestore index on the news story date.

   Show answer

   Answer: C

   Explanation

   C. Must decrease cost and latency. Creating or deploying anything would likely cost more, so eliminate B and D. That leaves A and C. A global audience strongly suggests serving content via Google’s Content Delivery Network. Changing the isolation level won’t decrease cost or latency, so C is the best answer.

   Source: Adapted from community discussion — dynamic_dba

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6. Question 106 · 170 in bank

   You need to migrate a 1 TB PostgreSQL database from a Compute Engine VM to Cloud SQL for PostgreSQL. You want to ensure that there is minimal downtime during the migration. What should you do?

   • AExport the data from the existing database, and load the data into a new Cloud SQL database.
   • BUse Migrate for Compute Engine to complete the migration.
   • CUse Datastream to complete the migration.
   • DUse Database Migration Service to complete the migration.

   Show answer

   Answer: D

   Explanation

   D. The key is minimal downtime. That eliminates A. Migrate for Compute Engine operates at the VM level. That eliminates B. Migrating from a GCE VM to Cloud SQL is a classic use case for the Database Migration Service. D is the best answer.

   Source: Adapted from community discussion — dynamic_dba

   References

   • Google Cloud documentation

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7. Question 107 · 170 in bank

   You have a large Cloud SQL for PostgreSQL instance. The database instance is not mission-critical, and you want to minimize operational costs. What should you do to lower the cost of backups in this environment?

   • ASet the automated backups to occur every other day to lower the frequency of backups.
   • BChange the storage tier of the automated backups from solid-state drive (SSD) to hard disk drive (HDD).
   • CSelect a different region to store your backups.
   • DReduce the number of automated backups that are retained to two (2).

   Show answer

   Answer: D

   Explanation

   By default, for each instance, Cloud SQL retains seven automated backups, in addition to on-demand backups. You can configure how many automated backups to retain (from 1 to 365). We charge a lower rate for backup storage than for other types of instances. https://cloud.google.com/sql/docs/mysql/backup-recovery/backups

   Source: Adapted from community discussion — PrtkKA

   References

   • Google Cloud documentation

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8. Question 108 · 170 in bank

   You are the primary DBA of a Cloud SQL for PostgreSQL database that supports 6 enterprise applications in production. You used Cloud SQL Insights to identify inefficient queries and now need to identify the application that is originating the inefficient queries. You want to follow Google-recommended practices. What should you do?

   • AShut down and restart each application.
   • BWrite a utility to scan database query logs.
   • CWrite a utility to scan application logs.
   • DUse query tags to add application-centric database monitoring.

   Show answer

   Answer: D

   Explanation

   D. A is just wrong on so many levels. B and C represent work and unless you know which SQL belongs to which application won’t actually help. First you need to add query tags to help identify application SQL. D is therefore correct. https://cloud.google.com/sql/docs/postgres/using-query-insights#filter_by_query_tags

   Source: Adapted from community discussion — dynamic_dba

   References

   • Google Cloud documentation

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9. Question 109 · 170 in bank

   You are designing a database strategy for a new web application. You plan to start with a small pilot in one country and eventually expand to millions of users in a global audience. You need to ensure that the application can run 24/7 with minimal downtime for maintenance. What should you do?

   • AUse Cloud Spanner in a regional configuration.
   • BUse Cloud Spanner in a multi-region configuration.
   • CUse Cloud SQL with cross-region replicas.
   • DUse highly available Cloud SQL with multiple zones.

   Show answer

   Answer: A

   Explanation

   https://cloud.google.com/spanner/docs/instance-configurations#move-instance You can move your Spanner instance from any instance configuration to any other instance configuration, including between regional and multi-region configurations. Moving your instance does not cause downtime, and Spanner continues to provide the usual transaction guarantees, including strong consistency, during the move. https://cloud.google.com/spanner/docs/move-instance https://cloud.google.com/spanner/docs/move-instance#how-instance-move

   Source: Adapted from community discussion — Pime13

   References

   • Google Cloud documentation
   • Google Cloud documentation

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10. Question 110 · 170 in bank

    You work for a large retail and ecommerce company that is starting to extend their business globally. Your company plans to migrate to Google Cloud. You want to use platforms that will scale easily, handle transactions with the least amount of latency, and provide a reliable customer experience. You need a storage layer for sales transactions and current inventory levels. You want to retain the same relational schema that your existing platform uses. What should you do?

    • AStore your data in Firestore in a multi-region location, and place your compute resources in one of the constituent regions.
    • BDeploy Cloud Spanner using a multi-region instance, and place your compute resources close to the default leader region.
    • CBuild an in-memory cache in Memorystore, and deploy to the specific geographic regions where your application resides.
    • DDeploy a Bigtable instance with a cluster in one region and a replica cluster in another geographic region.

    Show answer

    Answer: B

    Explanation

    B. The clues are "globally" and "relational schema". Relational rules out Firestore (A) and Bigtable (D). Cloud Spanner is both global in scale and relational, so it fits. So B.

    Source: Adapted from community discussion — dynamic_dba

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PCDBE practice, question 101. 170 questions available.