Google Professional Data Engineer Practice Test 1
Question 1
A design review evaluates this situation: A managed API intermittently returns 503, causing a multi-step data export workflow to fail permanently without preserving state. Which shortcut should the team MOST specifically avoid?
- Disable all retries to hide duplicate side effects without solving recovery.
- Trigger a year-end summary after the first daily task succeeds and mark it complete.
- Retry every request forever at full rate regardless of response code or side effect.
- Hardcode one UTC offset and assume all regions have no daylight changes.
Explanation
Correct Answer
C:Retry every request forever at full rate regardless of response code or side effect. This is the unsafe shortcut directly relevant to the stated system. A better approach is: Add supported retry conditions and exponential backoff with safe step checkpointing. Why: Workflow automation should use bounded backoff and preserve successful prior steps.
Incorrect Answers
A:Disable all retries to hide duplicate side effects without solving recovery. This addresses a different situation: An Airflow DAG reruns after scheduler recovery and reissues the same external billing update twice. The current scenario instead calls for the more directly applicable unsafe shortcut: Retry every request forever at full rate regardless of response code or side effect. The reason is that workflow automation should use bounded backoff and preserve successful prior steps.
B:Trigger a year-end summary after the first daily task succeeds and mark it complete. This addresses a different situation: A yearly backfill invokes all daily dependent tasks concurrently, while downstream aggregation assumes every day is already complete. The current scenario instead calls for the more directly applicable unsafe shortcut: Retry every request forever at full rate regardless of response code or side effect. The reason is that workflow automation should use bounded backoff and preserve successful prior steps.
D:Hardcode one UTC offset and assume all regions have no daylight changes. This addresses a different situation: A daily report must run at 08:00 business time, but the scheduler is configured in UTC and shifts unexpectedly after regional daylight changes. The current scenario instead calls for the more directly applicable unsafe shortcut: Retry every request forever at full rate regardless of response code or side effect. The reason is that workflow automation should use bounded backoff and preserve successful prior steps.
Question 2
The data engineering team must correct this issue: A retail database migration captures historical tables but fails to process updates made after the initial snapshot. Which controlled engineering action is MOST appropriate?
- Pilot managed Dataproc execution with approved Cloud Storage staging and tested dependencies.
- Evaluate an approved Transfer Appliance or equivalent controlled initial bulk-transfer approach.
- Create a verified backfill manifest and idempotent incremental import with distinct landing paths.
- Configure supported Datastream change capture with consistent backfill and lag monitoring.
Explanation
Correct Answer
D:Configure supported Datastream change capture with consistent backfill and lag monitoring. This addresses the specific problem while respecting business and technical constraints. Validate it by checking: A test mutation during backfill appears once in the destination after catch-up. Snapshot backfill and ongoing change-data capture must converge without gaps or double application.
Incorrect Answers
A:Pilot managed Dataproc execution with approved Cloud Storage staging and tested dependencies. This addresses a different situation: A batch Hadoop estate has custom Spark jobs and HDFS storage tightly coupled to aging servers. The current scenario instead calls for the more directly applicable engineering action: Configure supported Datastream change capture with consistent backfill and lag monitoring. The reason is that snapshot backfill and ongoing change-data capture must converge without gaps or double application.
B:Evaluate an approved Transfer Appliance or equivalent controlled initial bulk-transfer approach. This addresses a different situation: A research institute has hundreds of terabytes on isolated storage and cannot upload the first copy within its migration window. The current scenario instead calls for the more directly applicable engineering action: Configure supported Datastream change capture with consistent backfill and lag monitoring. The reason is that snapshot backfill and ongoing change-data capture must converge without gaps or double application.
C:Create a verified backfill manifest and idempotent incremental import with distinct landing paths. This addresses a different situation: A partner shares daily updates while an organization copies older archives into a new Cloud Storage lake. The current scenario instead calls for the more directly applicable engineering action: Configure supported Datastream change capture with consistent backfill and lag monitoring. The reason is that snapshot backfill and ongoing change-data capture must converge without gaps or double application.
Question 3
A Google Cloud data engineer is addressing: An events schema contains orders with many line items and analysts often query an order together with its items as one logical document. Which TWO complementary actions should the team take? Select TWO answers.
- Inspect query patterns, expected item cardinality, update frequency, and aggregation semantics.
- Review query job priority, resource contention, reservation design, and BI deadlines.
- Evaluate a nested repeated line-item representation and write correct UNNEST queries.
- Design governed fact and dimension tables with explicit surrogate or business keys and grain.
- Implement an appropriate type-2 dimension or equivalent temporal model with valid-time joins.
Explanation
Correct Answers
A:Inspect query patterns, expected item cardinality, update frequency, and aggregation semantics. This is the applicable diagnostic investigation. Its complementary step is: Evaluate a nested repeated line-item representation and write correct UNNEST queries. Together they address: BigQuery nested and repeated fields can model appropriate one-to-many analytical relationships with fewer joins.
C:Evaluate a nested repeated line-item representation and write correct UNNEST queries. This is the applicable controlled engineering response. Its complementary step is: Inspect query patterns, expected item cardinality, update frequency, and aggregation semantics. Together they address: BigQuery nested and repeated fields can model appropriate one-to-many analytical relationships with fewer joins.
Incorrect Answers
B:Review query job priority, resource contention, reservation design, and BI deadlines. This could be useful for another system: Interactive analysts share BigQuery capacity with long overnight transformations, causing unpredictable daytime dashboard latencies. For this situation, the necessary paired decisions are to examine (Inspect query patterns, expected item cardinality, update frequency, and aggregation semantics.) and to implement (Evaluate a nested repeated line-item representation and write correct UNNEST queries.).
D:Design governed fact and dimension tables with explicit surrogate or business keys and grain. This could be useful for another system: A retailer mixes orders, customers, products, and daily inventory measures in one wide duplicated table, making every report join and aggregate inconsistently. For this situation, the necessary paired decisions are to examine (Inspect query patterns, expected item cardinality, update frequency, and aggregation semantics.) and to implement (Evaluate a nested repeated line-item representation and write correct UNNEST queries.).
E:Implement an appropriate type-2 dimension or equivalent temporal model with valid-time joins. This could be useful for another system: Customer account tiers change over time but year-old invoices must be reported using the tier effective at the invoice date. For this situation, the necessary paired decisions are to examine (Inspect query patterns, expected item cardinality, update frequency, and aggregation semantics.) and to implement (Evaluate a nested repeated line-item representation and write correct UNNEST queries.).
Question 4
After applying the change, the team re-examines this condition: Two finance dashboards report different net revenue because they define discount treatment separately in handwritten SQL. Which result BEST verifies the improvement?
- A query reconciles with the underlying table within the documented refresh behavior.
- A report viewer sees allowed campaign totals but cannot extract protected customer records.
- A malicious test filter is treated as data rather than executing unintended SQL.
- Both reports reconcile net revenue for an agreed validation period.
Explanation
Correct Answer
D:Both reports reconcile net revenue for an agreed validation period. This measures the intended corrected behavior rather than only confirming a setting. Implemented action: Define governed revenue measures in an appropriate reusable semantic model or certified view. Central semantic definitions can prevent inconsistent business metrics across dashboards.
Incorrect Answers
A:A query reconciles with the underlying table within the documented refresh behavior. This addresses a different situation: A reporting team creates a materialized view but expects it to instantaneously reflect every base-table update under all query patterns. The current scenario instead calls for the more directly applicable verification result: Both reports reconcile net revenue for an agreed validation period. The reason is that central semantic definitions can prevent inconsistent business metrics across dashboards.
B:A report viewer sees allowed campaign totals but cannot extract protected customer records. This addresses a different situation: A marketing dashboard in Looker Studio displays performance summaries but the configured data source grants unrestricted access to restricted BigQuery customer fields. The current scenario instead calls for the more directly applicable verification result: Both reports reconcile net revenue for an agreed validation period. The reason is that central semantic definitions can prevent inconsistent business metrics across dashboards.
C:A malicious test filter is treated as data rather than executing unintended SQL. This addresses a different situation: A dashboard generates dynamic SQL by concatenating raw user text into filters and risks malformed or unsafe queries. The current scenario instead calls for the more directly applicable verification result: Both reports reconcile net revenue for an agreed validation period. The reason is that central semantic definitions can prevent inconsistent business metrics across dashboards.
Question 5
A Google Cloud architecture review finds: Datastream CDC events sometimes reach the destination out of order after reconnection and older rows overwrite current values. Which principle BEST explains the underlying data-engineering risk?
- CDC processing must respect source transaction order or version markers.
- Skewed keys can serialize distributed work and degrade parallel pipeline throughput.
- Managed integration tools can simplify source connectivity and repeatable mappings when requirements fit.
- Pipeline execution guarantees do not automatically make non-idempotent external side effects exactly once.
Explanation
Correct Answer
A:CDC processing must respect source transaction order or version markers. This principle identifies the relevant workload or governance requirement. The engineer should first examine: Review source log positions, change timestamps, key identities, and destination merge semantics. A focused corrective action is: Apply CDC changes using reliable source sequence/version ordering with replay safeguards.
Incorrect Answers
B:Skewed keys can serialize distributed work and degrade parallel pipeline throughput. This addresses a different situation: A Dataflow group-by-key stage slows because almost all events share one constant grouping value. The current scenario instead calls for the more directly applicable principle: CDC processing must respect source transaction order or version markers. The reason is that cDC processing must respect source transaction order or version markers.
C:Managed integration tools can simplify source connectivity and repeatable mappings when requirements fit. This addresses a different situation: A team has several supported relational sources and needs standard cleansing workflows but maintains dozens of brittle custom extraction scripts. The current scenario instead calls for the more directly applicable principle: CDC processing must respect source transaction order or version markers. The reason is that cDC processing must respect source transaction order or version markers.
D:Pipeline execution guarantees do not automatically make non-idempotent external side effects exactly once. This addresses a different situation: An engineer claims an exactly-once Dataflow pipeline makes arbitrary external API side effects impossible to duplicate. The current scenario instead calls for the more directly applicable principle: CDC processing must respect source transaction order or version markers. The reason is that cDC processing must respect source transaction order or version markers.
Question 6
A Google Cloud data engineer is addressing: A payment streaming system is operationally critical, but monthly experimentation triggers heavy resource contention and delayed settlement events. Which TWO complementary actions should the team take? Select TWO answers.
- Use appropriate interactive and batch workload controls with guaranteed critical capacity.
- Model an appropriate BigQuery Editions capacity reservation with planned commitments.
- Review reservation assignments, burst schedule, idle capacity, and job limits.
- Protect streaming settlement capacity and schedule noncritical experiments appropriately.
- Inspect queue lag, concurrency controls, reservation usage, and critical event SLAs.
Explanation
Correct Answers
D:Protect streaming settlement capacity and schedule noncritical experiments appropriately. This is the applicable controlled engineering response. Its complementary step is: Inspect queue lag, concurrency controls, reservation usage, and critical event SLAs. Together they address: Business-critical data processing should have planned resource isolation and failover controls.
E:Inspect queue lag, concurrency controls, reservation usage, and critical event SLAs. This is the applicable diagnostic investigation. Its complementary step is: Protect streaming settlement capacity and schedule noncritical experiments appropriately. Together they address: Business-critical data processing should have planned resource isolation and failover controls.
Incorrect Answers
A:Use appropriate interactive and batch workload controls with guaranteed critical capacity. This could be useful for another system: A same-day executive dashboard competes with a large nonurgent nightly historical rebuild. For this situation, the necessary paired decisions are to examine (Inspect queue lag, concurrency controls, reservation usage, and critical event SLAs.) and to implement (Protect streaming settlement capacity and schedule noncritical experiments appropriately.).
B:Model an appropriate BigQuery Editions capacity reservation with planned commitments. This could be useful for another system: A platform has steady high-volume SQL demand but is paying unpredictable per-query cost while finance requires capacity budgets. For this situation, the necessary paired decisions are to examine (Inspect queue lag, concurrency controls, reservation usage, and critical event SLAs.) and to implement (Protect streaming settlement capacity and schedule noncritical experiments appropriately.).
C:Review reservation assignments, burst schedule, idle capacity, and job limits. This could be useful for another system: A data science team needs occasional huge feature-engineering runs but competes with a permanently reserved reporting workload. For this situation, the necessary paired decisions are to examine (Inspect queue lag, concurrency controls, reservation usage, and critical event SLAs.) and to implement (Protect streaming settlement capacity and schedule noncritical experiments appropriately.).
Question 7
A Google Cloud data engineer is addressing: A small business runs a conventional PostgreSQL order service and needs managed backups and routine high availability without massive global horizontal write scale. Which TWO complementary actions should the team take? Select TWO answers.
- Use a suitable Cloud SQL edition and HA configuration with controlled migrations.
- Check engine compatibility, transaction volume, connection patterns, HA needs, and backups.
- Review transaction isolation needs, region placement, query patterns, and write contention.
- Choose a Firestore document model with carefully scoped security rules and indexes.
- Benchmark a compatible AlloyDB deployment with appropriate read pools and operational design.
Explanation
Correct Answers
A:Use a suitable Cloud SQL edition and HA configuration with controlled migrations. This is the applicable controlled engineering response. Its complementary step is: Check engine compatibility, transaction volume, connection patterns, HA needs, and backups. Together they address: Cloud SQL is a managed relational option for compatible transactional application workloads.
B:Check engine compatibility, transaction volume, connection patterns, HA needs, and backups. This is the applicable diagnostic investigation. Its complementary step is: Use a suitable Cloud SQL edition and HA configuration with controlled migrations. Together they address: Cloud SQL is a managed relational option for compatible transactional application workloads.
Incorrect Answers
C:Review transaction isolation needs, region placement, query patterns, and write contention. This could be useful for another system: A global order platform needs strongly consistent relational transactions across geographic users and plans to scale beyond a single traditional database instance. For this situation, the necessary paired decisions are to examine (Check engine compatibility, transaction volume, connection patterns, HA needs, and backups.) and to implement (Use a suitable Cloud SQL edition and HA configuration with controlled migrations.).
D:Choose a Firestore document model with carefully scoped security rules and indexes. This could be useful for another system: A mobile field-work app stores flexible nested inspection documents and synchronizes changes through supported client libraries. For this situation, the necessary paired decisions are to examine (Check engine compatibility, transaction volume, connection patterns, HA needs, and backups.) and to implement (Use a suitable Cloud SQL edition and HA configuration with controlled migrations.).
E:Benchmark a compatible AlloyDB deployment with appropriate read pools and operational design. This could be useful for another system: A PostgreSQL-compatible application has intensive operational transactions plus complex analytical queries and wants compatible managed performance options. For this situation, the necessary paired decisions are to examine (Check engine compatibility, transaction volume, connection patterns, HA needs, and backups.) and to implement (Use a suitable Cloud SQL edition and HA configuration with controlled migrations.).
Question 8
The data engineering team must correct this issue: A team has several supported relational sources and needs standard cleansing workflows but maintains dozens of brittle custom extraction scripts. Which controlled engineering action is MOST appropriate?
- Build an approved Cloud Data Fusion pipeline with validated source mappings and target schema.
- Tune adaptive execution and partitions or repartition skewed keys according to the workload.
- Use appropriately sized ephemeral Dataproc job clusters or serverless Spark execution.
- Configure Apache Beam windows and late-data handling appropriate to the report contract.
Explanation
Correct Answer
A:Build an approved Cloud Data Fusion pipeline with validated source mappings and target schema. This addresses the specific problem while respecting business and technical constraints. Validate it by checking: A sample source change is ingested and transformed consistently without manual code edits. Managed integration tools can simplify source connectivity and repeatable mappings when requirements fit.
Incorrect Answers
B:Tune adaptive execution and partitions or repartition skewed keys according to the workload. This addresses a different situation: A Dataproc Spark batch shuffles terabytes into a handful of very large partitions and regularly runs out of memory. The current scenario instead calls for the more directly applicable engineering action: Build an approved Cloud Data Fusion pipeline with validated source mappings and target schema. The reason is that managed integration tools can simplify source connectivity and repeatable mappings when requirements fit.
C:Use appropriately sized ephemeral Dataproc job clusters or serverless Spark execution. This addresses a different situation: A once-weekly Spark transformation uses a permanently running Dataproc cluster that sits idle most of the week. The current scenario instead calls for the more directly applicable engineering action: Build an approved Cloud Data Fusion pipeline with validated source mappings and target schema. The reason is that managed integration tools can simplify source connectivity and repeatable mappings when requirements fit.
D:Configure Apache Beam windows and late-data handling appropriate to the report contract. This addresses a different situation: A fraud model groups purchases into ten-minute windows, but late device clocks place events into the wrong billing period. The current scenario instead calls for the more directly applicable engineering action: Build an approved Cloud Data Fusion pipeline with validated source mappings and target schema. The reason is that managed integration tools can simplify source connectivity and repeatable mappings when requirements fit.
Question 9
Before modifying the data platform, the team observes: A yearly backfill invokes all daily dependent tasks concurrently, while downstream aggregation assumes every day is already complete. Which evidence should the engineer examine FIRST?
- Inspect BigQuery job statistics, query projections, filters, and data partitions.
- Inspect HTTP status patterns, retry policy, workflow state, and downstream idempotency.
- Examine task graph, partition completeness, retries, and downstream data freshness.
- Inspect Cloud Scheduler timezone, cron expression, daylight rules, and report SLA.
Explanation
Correct Answer
C:Examine task graph, partition completeness, retries, and downstream data freshness. This evidence directly tests the uncertain part of the described system. Backfill workflows need dependency awareness and capacity controls. A controlled response is: Create a parameterized backfill DAG with ordered readiness checks and bounded parallelism.
Incorrect Answers
A:Inspect BigQuery job statistics, query projections, filters, and data partitions. This addresses a different situation: A reporting application repeatedly runs SELECT star against a wide event table and billing spikes even though it needs five fields. The current scenario instead calls for the more directly applicable investigation: Examine task graph, partition completeness, retries, and downstream data freshness. The reason is that backfill workflows need dependency awareness and capacity controls.
B:Inspect HTTP status patterns, retry policy, workflow state, and downstream idempotency. This addresses a different situation: A managed API intermittently returns 503, causing a multi-step data export workflow to fail permanently without preserving state. The current scenario instead calls for the more directly applicable investigation: Examine task graph, partition completeness, retries, and downstream data freshness. The reason is that backfill workflows need dependency awareness and capacity controls.
D:Inspect Cloud Scheduler timezone, cron expression, daylight rules, and report SLA. This addresses a different situation: A daily report must run at 08:00 business time, but the scheduler is configured in UTC and shifts unexpectedly after regional daylight changes. The current scenario instead calls for the more directly applicable investigation: Examine task graph, partition completeness, retries, and downstream data freshness. The reason is that backfill workflows need dependency awareness and capacity controls.
Question 10
After applying the change, the team re-examines this condition: A research lake contains both public scientific data and restricted patient samples under one bucket with unrestricted reader roles. Which result BEST verifies the improvement?
- An incompatible JSON change is flagged and does not silently enter certified lake tables.
- The public researcher retrieves allowed files but cannot list or read restricted patient objects.
- An authorized researcher finds the correct lake dataset and understands its ownership and sensitivity.
- Unused scratch output expires while legal records and required lineage artifacts remain intact.
Explanation
Correct Answer
B:The public researcher retrieves allowed files but cannot list or read restricted patient objects. This measures the intended corrected behavior rather than only confirming a setting. Implemented action: Create segregated governed storage or lake access policies with least-privilege permissions. Lake security should enforce data-domain access and classification boundaries.
Incorrect Answers
A:An incompatible JSON change is flagged and does not silently enter certified lake tables. This addresses a different situation: Multiple departments publish raw JSON to a shared lake with inconsistent field definitions that break downstream reusable tables. The current scenario instead calls for the more directly applicable verification result: The public researcher retrieves allowed files but cannot list or read restricted patient objects. The reason is that lake security should enforce data-domain access and classification boundaries.
C:An authorized researcher finds the correct lake dataset and understands its ownership and sensitivity. This addresses a different situation: Researchers place thousands of raw objects in a data lake and cannot identify schemas, ownership, or classification. The current scenario instead calls for the more directly applicable verification result: The public researcher retrieves allowed files but cannot list or read restricted patient objects. The reason is that lake security should enforce data-domain access and classification boundaries.
D:Unused scratch output expires while legal records and required lineage artifacts remain intact. This addresses a different situation: A lake accumulates experimental intermediate outputs that cost more than final retained datasets and lacks automated expiration. The current scenario instead calls for the more directly applicable verification result: The public researcher retrieves allowed files but cannot list or read restricted patient objects. The reason is that lake security should enforce data-domain access and classification boundaries.