Google PCA Analysing and Optimising Technical and Business Processes Practice Test 5 — 15 Questions

Question 1

A company runs a global application that requires strong consistency across regions for financial transactions. Which database should they choose?

Accepted Answer

Cloud Spanner. Cloud Spanner provides global strong consistency and horizontal scaling. Bigtable offers eventual consistency. Firestore provides strong consistency within a region but not globally. Cloud SQL is regional.

Answer

Cloud SQL

Answer

Cloud Bigtable

Answer

Firestore

Question 2

A company needs to transfer 200 TB of data from on-premises to Cloud Storage within one week. The on-premises network upload speed is 100 Mbps. Which method should they use?

Accepted Answer

Order a Transfer Appliance. 200 TB at 100 Mbps = 200 * 1024 * 8 / (100/8) seconds ≈ 1,620,000 seconds ≈ 19 days, which exceeds one week. So network transfer is too slow. Transfer Appliance is a physical device for fast offline transfer. Storage Transfer Service is for cloud-to-cloud. gsutil rsync is an online tool. Velostrata is for VM migration.

Answer

Use Storage Transfer Service

Answer

Use gsutil rsync to transfer the data

Answer

Use Velostrata (Migrate for Compute Engine)

Question 3

A company wants to reduce costs for their BigQuery workloads. Which TWO actions will help achieve this?

Accepted Answer

Use clustered and partitioned tables to limit data scanned. Using flat-rate pricing with slot reservations provides predictable costs, and using clustered and partitioned tables reduces the amount of data scanned per query, lowering on-demand costs. Materialized views can reduce costs but are not always needed. Deleting datasets and compression are not relevant.

Answer

Enable compression on exported data

Answer

Delete unnecessary datasets

Answer

Use materialized views to pre-compute results

Question 4

A company wants to implement blameless postmortems as part of their SRE practices. Which THREE principles should they follow?

Accepted Answer

Create actionable recommendations to prevent recurrence. Blameless postmortems focus on learning from incidents without assigning blame. They should focus on system improvements, include everyone involved, and document findings. Assigning blame, only involving management, and ignoring fixes are contrary to blameless culture.

Answer

Only involve senior management in the review

Answer

Assign responsibility to the team that caused the incident

Question 5

A company runs batch analytics workloads each night on Compute Engine VMs. The workloads are fault-tolerant and can be interrupted. The finance team wants to reduce compute costs. Which Compute Engine pricing model should they use?

Accepted Answer

Preemptible VMs. Preemptible VMs offer the deepest discount (up to 91% off regular pricing) and are perfect for batch, fault-tolerant workloads that can be interrupted. Committed use discounts are for long-term, steady-state usage; sustained use discounts are automatic but smaller; and sole-tenant nodes are for isolation, not cost savings.

Answer

Committed use discounts (1-year or 3-year)

Answer

Sustained use discounts

Answer

Sole-tenant nodes

Question 6

A company is migrating 50 TB of on-premises file server data to Cloud Storage. The network bandwidth is limited to 100 Mbps. What is the most cost-effective and time-efficient migration method?

Accepted Answer

Use Transfer Appliance. Transfer Appliance is Google's physical device for transferring large amounts of data when network is slow or expensive. It avoids lengthy uploads over limited bandwidth. Storage Transfer Service is for cloud-to-cloud, not on-prem. gsutil cp and rsync over 100 Mbps would take weeks.

Answer

Use gsutil cp to copy files directly

Answer

Use gsutil rsync to synchronize

Answer

Use Storage Transfer Service

Question 7

A team uses BigQuery for real-time dashboarding. Queries on a large table take over 30 seconds. The table is date-partitioned and has high cardinality in the `user_id` column. Which optimization is MOST likely to reduce query latency?

Accepted Answer

Cluster the table on user_id. Clustering sorts data within partitions based on the clustering columns, which significantly improves query performance for filter and aggregation on those columns. `user_id` is high cardinality, so clustering on it helps. Partitioning alone is already done. Avoiding `SELECT *` helps but is not the most impactful here. Materialized views would help if the same aggregation is reused. Increasing slots costs money.

Answer

Use materialized views for all queries

Answer

Avoid using SELECT * in queries

Answer

Increase BigQuery slot reservations

Question 8

An organization deploys a web application on Compute Engine behind a global HTTPS load balancer. They want to reduce latency for users worldwide and minimize load on backend instances. Which GCP service should they use?

Accepted Answer

Cloud CDN. Cloud CDN uses Google's global edge caches to serve content closer to users, reducing latency and backend load. Cloud Armor provides security, Cloud NAT is for outbound connectivity, and VPC peering is for network connectivity, not caching.

Answer

Cloud Armor

Answer

Cloud NAT

Answer

VPC Network Peering

Question 9

A startup is designing a real-time leaderboard for a multiplayer game. The leaderboard must update within seconds of a score change and handle millions of concurrent players. Strong consistency is not required, but availability is critical. Which database is most suitable?

Accepted Answer

Cloud Bigtable. Cloud Bigtable is optimized for high-throughput, low-latency reads and writes, and can serve as a leaderboard backend if row keys are designed properly. It offers eventual consistency, which is acceptable here. Cloud Spanner provides strong consistency but is more expensive and may have higher latency. Firestore is good for real-time updates but may not handle millions of concurrent updates easily. Memorystore (Redis) can also do leaderboards but is not a database for persistent storage; it's a cache.

Answer

Cloud Memorystore

Answer

Cloud Spanner

Answer

Cloud Firestore

Question 10

A company has a Cloud SQL for PostgreSQL instance that experiences high connection overhead. Developers frequently open and close connections. Which solution reduces connection overhead without code changes?

Accepted Answer

Configure PgBouncer as a sidecar. Cloud SQL Auth Proxy provides secure connections but does not pool. PgBouncer is a connection pooler for PostgreSQL; it maintains a pool of connections and reuses them. Increasing max_connections doesn't reduce overhead. Using private IP alone doesn't pool.

Answer

Increase max_connections in Cloud SQL

Answer

Switch to Private IP

Answer

Use Cloud SQL Auth Proxy

Question 11

A company stores infrequently accessed data in Cloud Storage Standard class. To reduce costs, they want to automatically move objects older than 90 days to a lower-cost storage class. Which approach should they use?

Accepted Answer

Configure a lifecycle policy to transition to Archive class. Cloud Storage lifecycle policies allow automatic transitions between storage classes based on conditions like age. Setting a rule to transition from Standard to Nearline, Coldline, or Archive after 90 days is the correct approach. Object versioning keeps multiple versions but doesn't change class. Pub/Sub notifications notify events but don't act. gsutil rewrite can be scripted but is manual.

Answer

Use gsutil rewrite to manually change storage class

Answer

Set up Pub/Sub notifications for object changes

Answer

Enable object versioning

Question 12

A team runs a Cloud Spanner instance with a regional configuration. They need to increase write throughput for a global user base but are concerned about cost. What should they do?

Accepted Answer

Add more nodes to the instance. Adding nodes increases throughput and cost proportionally. Switching to multi-region increases latency for writes (due to synchronous replication) and cost. Using global indexes won't increase baseline write throughput. Recommending to use Firestore is not correct for this scenario.

Answer

Use global indexes

Answer

Migrate to Cloud Firestore in Datastore mode

Answer

Switch to a multi-region configuration

Question 13

A company wants to migrate a MySQL database running on-premises to Cloud SQL with minimal downtime. Which GCP service should they use?

Accepted Answer

Database Migration Service. Database Migration Service (DMS) supports homogeneous migrations for MySQL, PostgreSQL, and SQL Server with minimal downtime using continuous replication. Migrate for Compute Engine is for VM migration, Transfer Appliance for bulk data, and Storage Transfer Service for object storage.

Answer

Migrate for Compute Engine

Answer

Storage Transfer Service

Answer

Transfer Appliance

Question 14

An e-commerce application uses Firestore for product catalog. They need to run complex analytical queries on the catalog data, such as aggregations and joins, without impacting production performance. What is the best approach?

Accepted Answer

Export Firestore data to BigQuery for analytics. Firestore is not designed for analytical queries. Exporting to BigQuery allows running complex analytics without impacting Firestore performance. Using a second Firestore database increases cost but doesn't improve analytics. Cloud SQL does not natively integrate with Firestore. Using the `!=` operator doesn't solve analytical needs.

Answer

Create a second Firestore database for analytics

Answer

Use Cloud SQL to query Firestore directly

Answer

Use Firestore `!=` operator to filter data

Question 15

A company has a Cloud Bigtable instance with 10 nodes. They notice read latency increases during peak hours. Monitoring shows CPU utilization at 70%. Which action will most effectively reduce read latency?

Accepted Answer

Increase the number of nodes. High CPU utilization (70%) indicates the cluster is stressed. Adding nodes increases throughput and reduces latency. SSDs are default, so not a factor. Row key redesign would require application changes. Table splitting is automatic.

Answer

Switch from HDD to SSD

Answer

Redesign row keys to avoid hotspots

Answer

Split the tables into more tablets