PCDE Practice Test 26 — 15 Questions

Question 1

A company needs to track costs across different teams and projects. They want to see detailed breakdowns by team, environment, and application. Which GCP feature should they use to tag resources for cost analysis?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Resource labels. GCP resource labels are key-value pairs that can be attached to most resources (VMs, buckets, datasets, etc.) and are the primary mechanism for cost attribution and filtering in Cloud Billing reports. By labeling resources with team, environment, and application keys, the company can break down costs along those dimensions in the billing console and exports.

Answer

Billing budgets

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Network tags

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Billing export to BigQuery

Question 2

A team is designing a Cloud Spanner schema for an e-commerce platform. They have 'Customer' and 'Order' tables and want to ensure that queries for all orders of a specific customer are efficient. Which schema design approach should they use?

Accepted Answer

Interleave the 'Order' table under the 'Customer' table with CustomerID as the first part of Orders' primary key. Spanner supports interleaving tables, where child rows are stored physically near the parent row. Interleaving Orders under Customers using the CustomerID as the first part of the primary key in Orders makes queries for all orders of a customer efficient by colocating related data.

Answer

Use a single table with denormalized customer and order data

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Use a secondary index on CustomerID in the Order table

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Create a separate 'Order' table with a foreign key to Customer

Question 3

During a DMS continuous migration from MySQL to Cloud SQL, the full dump phase completed successfully, but the CDC phase is failing with 'Error: binary log not found' after a few minutes. The source MySQL has binary logs enabled. What is the most likely cause?

Accepted Answer

The binary logs were purged due to a short binlog_expire_logs_seconds setting.. DMS continuous migration relies on reading the source MySQL binary logs to replicate ongoing changes after the initial full dump. If binlog_expire_logs_seconds (or the older expire_logs_days) is set too low, MySQL purges binlog files before DMS has finished reading them, producing 'binary log not found' errors. The full dump succeeded, so connectivity and credentials are fine — the failure is specifically that the required binlog position no longer exists on the source.

Answer

The DMS connection profile has incorrect SSL settings.

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The source database was restarted and binary logs were reset.

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The source MySQL server has run out of disk space.

Question 4

An engineer needs to create an SLO in Cloud Monitoring for a service that processes requests. The SLO should measure the proportion of requests that complete successfully within 300ms. The metric type for successful requests is custom.googleapis.com/myapp/success_count and for total requests is custom.googleapis.com/myapp/total_count. Which type of SLO should they create?

Accepted Answer

Request-based SLO using two metrics (good count / valid count). A request-based SLO with two metrics (good count / valid count) is correct because the SLO measures the ratio of successful requests to total requests. Cloud Monitoring supports this pattern when separate counters exist for good events and total events, computing the ratio as the SLI.

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Availability SLO using a single metric for uptime

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Request-based SLO using a single distribution metric

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Window-based SLO with metric distribution

Question 5

A team wants to reduce toil from manual database backups. They estimate the toil takes 10 hours per week. What is the maximum amount of toil they should allow to keep toil under 50% of their time according to SRE best practices?

Accepted Answer

20 hours per week. According to SRE best practices, toil should be capped at 50% of an engineer's time, leaving the other 50% for engineering work that reduces toil. If a team works 40 hours per week, 50% is 20 hours. Therefore, the maximum toil allowed is 20 hours per week.

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5 hours per week

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40 hours per week

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10 hours per week

Question 6

A data analytics company uses Bigtable for high-throughput writes. They notice that some rows are receiving a disproportionate number of reads and writes, causing performance degradation. Which tool should they use to identify and resolve this hot spotting issue?

Accepted Answer

Key Visualiser. Key Visualizer is the correct tool because it is specifically designed to analyze Bigtable access patterns and visualize hot spotting—where a small number of rows or row ranges receive a disproportionate share of reads and writes. It provides heatmaps and time-series graphs that pinpoint the exact keys causing performance degradation, enabling you to redesign your row keys or implement salting to distribute load evenly.

Answer

cbt tool

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Cloud Logging

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Cloud Monitoring

Question 7

Which TWO data types are supported in Cloud Spanner schemas?

Accepted Answer

ARRAY. ARRAY is a supported data type in Cloud Spanner, allowing you to store ordered lists of elements of the same primitive type (e.g., ARRAY, ARRAY). This is essential for modeling one-to-many relationships without requiring separate tables, and it integrates seamlessly with Cloud Spanner's query engine for array operations.

Answer

GEOMETRY

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TEXT

Answer

TINYINT

Question 8

A company runs Memorystore for Redis with a Standard tier instance. They want to scale to higher throughput and memory capacity beyond the current tier limits. Which TWO actions should they take?

Accepted Answer

Enable Redis Cluster to shard data across multiple nodes.. Redis Cluster shards data across multiple nodes, allowing horizontal scaling beyond the limits of a single Standard tier instance. This enables higher throughput and memory capacity by distributing the dataset across multiple primary nodes, each handling a subset of the keyspace.

Answer

Switch from HDD to SSD storage.

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Add a cross-region replica to increase read capacity.

Answer

Increase the maxmemory setting beyond the tier limit.

Question 9

A company has a Cloud Bigtable cluster using HDD storage. They are migrating to a workload that requires lower latency, so they need to switch to SSD storage. How should they accomplish this?

Accepted Answer

Create a new Bigtable cluster with SSD storage in the same instance, replicate data, then delete the old cluster.. Cloud Bigtable does not support in-place conversion of storage type from HDD to SSD. The proper migration path is to create a new cluster with SSD storage within the same instance, enable replication to keep data synchronized, and then delete the old HDD cluster. This approach minimizes downtime and ensures data consistency.

Answer

Add more nodes to the existing cluster to improve latency.

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Export data to Avro files, create a new SSD cluster, and import the data.

Answer

Modify the existing cluster's storage type to SSD using the Cloud Console.

Question 10

A team uses Cloud Run for a web application that experiences sporadic traffic. They want to minimize cold starts without incurring costs when there are no requests. Which configuration should they use?

Accepted Answer

Set min instances to a value greater than 0. Setting min instances to a value greater than 0 keeps at least one (or more) container instance warm and ready to serve requests, eliminating cold starts for the baseline traffic. Because Cloud Run only bills for instances that are actually running, setting min instances to 0 (the default) allows scale-to-zero but causes cold starts on the first request after idle. CPU always-on and concurrency settings affect performance and cost but do not prevent cold starts.

Answer

Set min instances to 0

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Set CPU always-on to true

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Set concurrency to 1000

Question 11

A team wants to reduce toil by automating a manual process that generates a report from Cloud Logging logs and emails it weekly. Which solution is most cost-effective and requires minimal operational overhead?

Accepted Answer

Cloud Scheduler + Cloud Functions. Cloud Scheduler + Cloud Functions is the most cost-effective and low-overhead solution. Cloud Scheduler triggers a Cloud Function on a schedule, and the function can query Cloud Logging, generate a report, and send an email. This is serverless, pay-per-use, and requires minimal management.

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Cloud Run job manually started

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Cloud Build trigger on schedule

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Cloud Composer (Airflow) DAG

Question 12

An SRE team is setting up an on-call rotation for incident response. They want to use a tool that integrates with Cloud Monitoring and can escalate incidents if not acknowledged. Which service should they integrate with Cloud Monitoring?

Accepted Answer

PagerDuty. PagerDuty is the industry-standard incident response and on-call management tool that integrates natively with Cloud Monitoring to route alerts, manage on-call schedules, and escalate unacknowledged incidents. It provides the escalation policies and notification mechanisms that Cloud Monitoring alone does not offer.

Answer

Cloud Pub/Sub

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Cloud Functions

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Cloud Run

Question 13

A team's SLO for availability is 99.9% over a 30-day window. They have consumed 80% of their error budget halfway through the month. What is the remaining allowed downtime for the rest of the month?

Accepted Answer

About 8 minutes 38 seconds. A 99.9% availability SLO over 30 days allows 0.1% downtime, which is about 43 minutes 12 seconds total. If 80% of the error budget is consumed, 20% remains, and 20% of 43m12s is about 8 minutes 38 seconds.

Answer

About 17 minutes 17 seconds

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About 34 minutes 34 seconds

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About 43 minutes 12 seconds

Question 14

A company uses Cloud Spanner for a global inventory application. They need to add a new index to a large table without downtime. What is the recommended approach?

Accepted Answer

Use CREATE INDEX; Spanner handles it as a non-blocking operation. Cloud Spanner's CREATE INDEX operation is inherently non-blocking; it performs the index backfill as a background process without locking the table or blocking reads and writes. This allows the index to be added to a large table with zero downtime, as Spanner manages the consistency and availability of the data throughout the operation.

Answer

Create the index using ALTER TABLE with 'ONLINE' clause

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Use gcloud spanner databases ddl update with --async flag

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Take a backup, create index on a new instance, and switch traffic

Question 15

During an incident, the incident commander notices that multiple teams are working on the same issue without coordination. Which structure should be implemented to improve incident response?

Accepted Answer

Assign a single incident commander to coordinate all teams. Assigning a single incident commander establishes a clear chain of command and a central point of coordination, which is a core principle of incident management frameworks like ICS (Incident Command System). This prevents duplicate efforts and ensures all teams work toward a common plan. It directly addresses the lack of coordination described.

Answer

Use a chatbot to broadcast updates without a commander

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Have each team work independently and report after resolution

Answer

Escalate to the VP of Engineering to make decisions