Databricks Certified Data Engineer Associate Practice Test 9
Question 80
The farm_loan_transaction_history_coastal pipeline at Agricultural credit union has this failure: farm_loan_transaction_history_coastal job runs hourly although only one file arrives most days. The team observed that execution history shows repeated empty runs with compute startup cost. Business requirement: process each new delivered file promptly without idle polling. The new approach is deployed. The current task is to prove correct output and authorized behavior, not just successful installation. What test most directly proves the requirement is satisfied?
- Inspect file arrival pattern, supported trigger source and job startup overhead for farm_loan_transaction_history_coastal
- Run a full pipeline every minute even if no files arrive at Agricultural credit union
- Enable trigger in staging and test a new object arrival
- Upload a test file and confirm exactly the expected run fires
Explanation
Correct Answer
D:Upload a test file and confirm exactly the expected run fires directly tests the behavior that should change after the correction. With the observed evidence (execution history shows repeated empty runs with compute startup cost), the acceptance result must demonstrate actual data or permission correctness, while retaining the requirement that process each new delivered file promptly without idle polling.
Incorrect Answers
A:Inspect file arrival pattern, supported trigger source and job startup overhead for farm_loan_transaction_history_coastal could clarify the original fault, but the available evidence already establishes its scope; it is not the post-change acceptance test now requested. The farm_loan_transaction_history_coastal workflow still requires that process each new delivered file promptly without idle polling.
B:Repetitive empty executions waste compute and cost. The proposed action (Run a full pipeline every minute even if no files arrive at Agricultural credit union) does not meet the requirement that process each new delivered file promptly without idle polling, nor does it constitute the post-change acceptance test.
C:Enable trigger in staging and test a new object arrival may introduce a correction, but the question does not ask for installation or migration. A rollout alone cannot replace the post-change acceptance test, especially given the evidence that execution history shows repeated empty runs with compute startup cost.
Question 81
At Environmental inspection office, the sampling field notes workflow depends on sampling_field_notes_metro. Engineers report that sampling_field_notes_metro serves an exploratory dashboard counting hundreds of millions of unique session IDs; the evidence is that exact count-distinct creates high aggregation cost during interactive prototyping. They require that users explicitly accept bounded approximation in exchange for speed. The new approach is deployed. The current task is to prove correct output and authorized behavior, not just successful installation. Which post-change acceptance check is strongest?
- Trial approximate aggregation on representative samples against exact ground truth
- Substitute sum(session_id) as an estimate of unique sessions at Environmental inspection office
- Compare estimate error and latency to the agreed tolerance
- Measure cardinality, acceptable error and resource use for sampling_field_notes_metro
Explanation
Correct Answer
C:Compare estimate error and latency to the agreed tolerance directly tests the behavior that should change after the correction. With the observed evidence (exact count-distinct creates high aggregation cost during interactive prototyping), the acceptance result must demonstrate actual data or permission correctness, while retaining the requirement that users explicitly accept bounded approximation in exchange for speed.
Incorrect Answers
A:Trial approximate aggregation on representative samples against exact ground truth may introduce a correction, but the question does not ask for installation or migration. A rollout alone cannot replace the post-change acceptance test, especially given the evidence that exact count-distinct creates high aggregation cost during interactive prototyping.
B:Adding identifiers is not a distinct-count estimator. The proposed action (Substitute sum(session_id) as an estimate of unique sessions at Environmental inspection office) does not meet the requirement that users explicitly accept bounded approximation in exchange for speed, nor does it constitute the post-change acceptance test.
D:Measure cardinality, acceptable error and resource use for sampling_field_notes_metro could clarify the original fault, but the available evidence already establishes its scope; it is not the post-change acceptance test now requested. The sampling_field_notes_metro workflow still requires that users explicitly accept bounded approximation in exchange for speed.
Question 82
A data engineer at Optical instrument maker is responsible for device calibration readings. The derived column withColumn issue is that device_calibration_readings_urban needs a normalized discount amount but the pipeline overwrites the source field. The supporting evidence is that code review shows an arithmetic expression replacing original gross_sales. The engineer must ensure that auditors require gross and net amounts independently. The new approach is deployed. The current task is to prove correct output and authorized behavior, not just successful installation. What evidence establishes that correct output is maintained?
- Check discount scenarios and verify both gross and net are correct
- Overwrite the only gross amount and discard source values at Optical instrument maker
- Inspect expression dependencies and column lineage for device_calibration_readings_urban
- Deploy the expression to silver with explicit numeric-type handling
Explanation
Correct Answer
A:Check discount scenarios and verify both gross and net are correct directly tests the behavior that should change after the correction. With the observed evidence (code review shows an arithmetic expression replacing original gross_sales), the acceptance result must demonstrate actual data or permission correctness, while retaining the requirement that auditors require gross and net amounts independently.
Incorrect Answers
B:Overwriting original financial evidence breaks reconciliation. The proposed action (Overwrite the only gross amount and discard source values at Optical instrument maker) does not meet the requirement that auditors require gross and net amounts independently, nor does it constitute the post-change acceptance test.
C:Inspect expression dependencies and column lineage for device_calibration_readings_urban could clarify the original fault, but the available evidence already establishes its scope; it is not the post-change acceptance test now requested. The device_calibration_readings_urban workflow still requires that auditors require gross and net amounts independently.
D:Deploy the expression to silver with explicit numeric-type handling may introduce a correction, but the question does not ask for installation or migration. A rollout alone cannot replace the post-change acceptance test, especially given the evidence that code review shows an arithmetic expression replacing original gross_sales.
Question 83
The land_cover_observations_south pipeline at Satellite imagery startup has this failure: land_cover_observations_south Delta queries slow after the filter distribution changes. The team observed that query profile shows increased file scanning despite healthy worker utilization. Business requirement: performance optimization must adapt to predicate patterns. The failure and requirements have been diagnosed; the team must select the lasting pipeline or governance approach. What lasting solution should be selected for the verified conditions?
- Monitor scan-to-result ratio and clustering upkeep for land_cover_observations_south
- Inspect clustering columns and actual filter patterns for land_cover_observations_south
- Choose suitable liquid clustering keys and supported optimization maintenance
- Add a new physical partition for every possible filter value at Satellite imagery startup
Explanation
Correct Answer
C:Choose suitable liquid clustering keys and supported optimization maintenance is the intended durable approach for land_cover_observations_south: it addresses the verified problem (land_cover_observations_south Delta queries slow after the filter distribution changes) while preserving the required behavior (performance optimization must adapt to predicate patterns). A diagnostic or monitoring step alone would not create this target-state behavior.
Incorrect Answers
A:Monitor scan-to-result ratio and clustering upkeep for land_cover_observations_south would help detect future recurrence, but metrics alone do not deliver the target approach. The land_cover_observations_south requirement is that performance optimization must adapt to predicate patterns.
B:Inspect clustering columns and actual filter patterns for land_cover_observations_south could clarify the original fault, but the available evidence already establishes its scope; it is not the target approach now requested. The land_cover_observations_south workflow still requires that performance optimization must adapt to predicate patterns.
D:Extreme partitioning creates metadata overhead. The proposed action (Add a new physical partition for every possible filter value at Satellite imagery startup) does not meet the requirement that performance optimization must adapt to predicate patterns, nor does it constitute the target approach.
Question 84
The customer_order_changes_metro pipeline at Online apparel cooperative has this failure: customer_order_changes_metro job points to the dev catalog even after deploying with the production target. The team observed that configuration shows an unresolved dev catalog literal in the bundle. Business requirement: one codebase must deploy safely to different UC environments. The target approach is approved. The current task is to introduce it safely with bounded scope and rollback. What should be done next to deploy the approved solution?
- Parameterize environment-specific catalog and resources using Declarative Automation Bundle targets
- Replace the Git code with a different unreviewed copy for every environment at Online apparel cooperative
- Inspect resolved deployment and execute job under both targets to confirm isolation
- Add tested prod variable overrides and run validation before deploy
Explanation
Correct Answer
D:Add tested prod variable overrides and run validation before deploy provides a bounded way to introduce the approved solution into customer_order_changes_metro and detect an early mismatch. The existing signal is configuration shows an unresolved dev catalog literal in the bundle; a staged change protects the service requirement (one codebase must deploy safely to different UC environments) and makes rollback practical.
Incorrect Answers
A:Parameterize environment-specific catalog and resources using Declarative Automation Bundle targets is a plausible lasting design once chosen, but it does not perform the controlled implementation step at this stage. In the customer_order_changes_metro scenario, the observed evidence is that configuration shows an unresolved dev catalog literal in the bundle; the requirement remains: one codebase must deploy safely to different UC environments.
B:Diverging codebases defeat controlled promotion. The proposed action (Replace the Git code with a different unreviewed copy for every environment at Online apparel cooperative) does not meet the requirement that one codebase must deploy safely to different UC environments, nor does it constitute the controlled implementation step.
C:Inspect resolved deployment and execute job under both targets to confirm isolation is a one-time acceptance check. It does not supply the controlled implementation step for customer_order_changes_metro; a passing test cannot substitute for the specific task now required.
Question 85
Consider the loan_repayment_events_island workload at Consumer finance platform: loan_repayment_events_island overnight export fires one hour early after daylight-saving changes. Inspection found that run history shows schedule configured in a different timezone than business cutoff. The governed outcome must ensure that the export must complete relative to the local reporting calendar. The failure and requirements have been diagnosed; the team must select the lasting pipeline or governance approach. Which data-engineering approach resolves the documented weakness?
- Monitor schedule drift, missed triggers and export deadline slips for loan_repayment_events_island
- Inspect schedule timezone, cron expression and daylight-saving policy for loan_repayment_events_island
- Assume all local timezones have the same UTC offset year-round at Consumer finance platform
- Configure Lakeflow scheduled trigger using an explicit timezone and cutoff
Explanation
Correct Answer
D:Configure Lakeflow scheduled trigger using an explicit timezone and cutoff is the intended durable approach for loan_repayment_events_island: it addresses the verified problem (loan_repayment_events_island overnight export fires one hour early after daylight-saving changes) while preserving the required behavior (the export must complete relative to the local reporting calendar). A diagnostic or monitoring step alone would not create this target-state behavior.
Incorrect Answers
A:Monitor schedule drift, missed triggers and export deadline slips for loan_repayment_events_island would help detect future recurrence, but metrics alone do not deliver the target approach. The loan_repayment_events_island requirement is that the export must complete relative to the local reporting calendar.
B:Inspect schedule timezone, cron expression and daylight-saving policy for loan_repayment_events_island could clarify the original fault, but the available evidence already establishes its scope; it is not the target approach now requested. The loan_repayment_events_island workflow still requires that the export must complete relative to the local reporting calendar.
C:Timezones with dst can shift relative to utc. The proposed action (Assume all local timezones have the same UTC offset year-round at Consumer finance platform) does not meet the requirement that the export must complete relative to the local reporting calendar, nor does it constitute the target approach.
Question 86
At Public weather agency, the liquid clustering maintenance workflow handles station observation files. The problem is that station_observation_files_east Delta queries slow after the filter distribution changes. Evidence: query profile shows increased file scanning despite healthy worker utilization. Constraint: performance optimization must adapt to predicate patterns. The new approach is deployed. The current task is to prove correct output and authorized behavior, not just successful installation. Which test should pass before the new flow is accepted?
- Add a new physical partition for every possible filter value at Public weather agency
- Inspect clustering columns and actual filter patterns for station_observation_files_east
- Recluster a pilot table and measure read/write behavior
- Compare representative query scan metrics and results before and after
Explanation
Correct Answer
D:Compare representative query scan metrics and results before and after directly tests the behavior that should change after the correction. With the observed evidence (query profile shows increased file scanning despite healthy worker utilization), the acceptance result must demonstrate actual data or permission correctness, while retaining the requirement that performance optimization must adapt to predicate patterns.
Incorrect Answers
A:Extreme partitioning creates metadata overhead. The proposed action (Add a new physical partition for every possible filter value at Public weather agency) does not meet the requirement that performance optimization must adapt to predicate patterns, nor does it constitute the post-change acceptance test.
B:Inspect clustering columns and actual filter patterns for station_observation_files_east could clarify the original fault, but the available evidence already establishes its scope; it is not the post-change acceptance test now requested. The station_observation_files_east workflow still requires that performance optimization must adapt to predicate patterns.
C:Recluster a pilot table and measure read/write behavior may introduce a correction, but the question does not ask for installation or migration. A rollout alone cannot replace the post-change acceptance test, especially given the evidence that query profile shows increased file scanning despite healthy worker utilization.
Question 87
The turbine_sensor_messages_coastal pipeline at Renewable energy operator has this failure: turbine_sensor_messages_coastal job succeeds for a developer but fails under the production scheduler. The team observed that audit logs show a personal identity has access that the service principal lacks. Business requirement: production execution must use a durable least-privilege identity. The target approach is approved. The current task is to introduce it safely with bounded scope and rollback. What should be done next to deploy the approved solution?
- Share the developer's personal access token as a permanent production secret at Renewable energy operator
- Execute a full run using the service principal and verify output
- Switch run-as after validating access to each dependency
- Configure a scoped service principal job identity with required UC privileges
Explanation
Correct Answer
C:Switch run-as after validating access to each dependency provides a bounded way to introduce the approved solution into turbine_sensor_messages_coastal and detect an early mismatch. The existing signal is audit logs show a personal identity has access that the service principal lacks; a staged change protects the service requirement (production execution must use a durable least-privilege identity) and makes rollback practical.
Incorrect Answers
A:Personal tokens are not durable least-privilege job identities. The proposed action (Share the developer's personal access token as a permanent production secret at Renewable energy operator) does not meet the requirement that production execution must use a durable least-privilege identity, nor does it constitute the controlled implementation step.
B:Execute a full run using the service principal and verify output is a one-time acceptance check. It does not supply the controlled implementation step for turbine_sensor_messages_coastal; a passing test cannot substitute for the specific task now required.
D:Configure a scoped service principal job identity with required UC privileges is a plausible lasting design once chosen, but it does not perform the controlled implementation step at this stage. In the turbine_sensor_messages_coastal scenario, the observed evidence is that audit logs show a personal identity has access that the service principal lacks; the requirement remains: production execution must use a durable least-privilege identity.
Question 88
Consider the land_cover_observations_highland workload at Satellite imagery startup: land_cover_observations_highland validation notebook computes the partition date but downstream tasks use yesterday by default. Inspection found that logs show successful validation for one date and export for another. The governed outcome must ensure that the exported partition must match the validated partition. The first acceptance run passed. The current task is to detect future regressions and changes over time. Which continuing signal best reveals recurrence or drift?
- Pass a validated task value to the dependent export task
- Run an out-of-order input and verify exported partition matches validated date
- Hardcode yesterday in every downstream task at Satellite imagery startup
- Monitor missing task values and inconsistent task parameters for land_cover_observations_highland
Explanation
Correct Answer
D:Monitor missing task values and inconsistent task parameters for land_cover_observations_highland creates recurring visibility into the failure mode (land_cover_observations_highland validation notebook computes the partition date but downstream tasks use yesterday by default). Unlike a single successful test, the measure can reveal drift, lag, or new failures after later source and deployment changes while the exported partition must match the validated partition.
Incorrect Answers
A:Pass a validated task value to the dependent export task is a plausible lasting design once chosen, but it does not perform continuing operational detection at this stage. In the land_cover_observations_highland scenario, the observed evidence is that logs show successful validation for one date and export for another; the requirement remains: the exported partition must match the validated partition.
B:Run an out-of-order input and verify exported partition matches validated date is a one-time acceptance check. It does not supply continuing operational detection for land_cover_observations_highland; a passing test cannot substitute for the specific task now required.
C:Hardcoded dates can diverge from validated data. The proposed action (Hardcode yesterday in every downstream task at Satellite imagery startup) does not meet the requirement that the exported partition must match the validated partition, nor does it constitute continuing operational detection.
Question 89
Consider the pollution_measurements_west workload at Air quality nonprofit: two concurrent writers update pollution_measurements_west and a reader sometimes sees inconsistent exported copies. Inspection found that the write log shows independent files were replaced while an ETL job was reading them. The governed outcome must ensure that readers require consistent committed versions without pausing ingest. The team has not selected a remedy. It first needs evidence that distinguishes the actual dependency or data fault. Which evidence-gathering action should precede an architectural change?
- Convert the staging copy and cut over readers only after commit and rollback tests
- Inspect commit history and concurrent writer conflict details for pollution_measurements_west
- Allow direct writers to replace arbitrary Parquet files while readers scan them at Air quality nonprofit
- Store pollution_measurements_west as a Delta table and rely on atomic transaction-log commits
Explanation
Correct Answer
B:Inspect commit history and concurrent writer conflict details for pollution_measurements_west directly investigates the evidence (the write log shows independent files were replaced while an ETL job was reading them) and distinguishes possible causes of two concurrent writers update pollution_measurements_west and a reader sometimes sees inconsistent exported copies. It establishes what must be corrected without assuming a fix before verifying the stated business requirement: readers require consistent committed versions without pausing ingest.
Incorrect Answers
A:Convert the staging copy and cut over readers only after commit and rollback tests may introduce a correction, but the question does not ask for installation or migration. A rollout alone cannot replace the required pre-change investigation, especially given the evidence that the write log shows independent files were replaced while an ETL job was reading them.
C:Uncoordinated file replacement cannot provide delta transaction guarantees. The proposed action (Allow direct writers to replace arbitrary Parquet files while readers scan them at Air quality nonprofit) does not meet the requirement that readers require consistent committed versions without pausing ingest, nor does it constitute the required pre-change investigation.
D:Store pollution_measurements_west as a Delta table and rely on atomic transaction-log commits is a plausible lasting design once chosen, but it does not perform the required pre-change investigation at this stage. In the pollution_measurements_west scenario, the observed evidence is that the write log shows independent files were replaced while an ETL job was reading them; the requirement remains: readers require consistent committed versions without pausing ingest.
Question 90
Consider the claims_payment_events_delta workload at Regional insurance broker: claims_payment_events_delta dashboard repeatedly scans years of silver transactions for daily rollups. Inspection found that SQL history shows expensive repeated aggregation on an otherwise stable reporting query. The governed outcome must ensure that analysts need low-latency aggregates refreshed on a defined cadence. The first acceptance run passed. The current task is to detect future regressions and changes over time. Which continuing signal best reveals recurrence or drift?
- Verify refresh applies new silver rows and queries return the expected totals
- Create a regular view and promise it stores its results between queries at Regional insurance broker
- Monitor gold refresh age and incremental-refresh failures for claims_payment_events_delta
- Publish a materialized view for precomputed frequently queried aggregates
Explanation
Correct Answer
C:Monitor gold refresh age and incremental-refresh failures for claims_payment_events_delta creates recurring visibility into the failure mode (claims_payment_events_delta dashboard repeatedly scans years of silver transactions for daily rollups). Unlike a single successful test, the measure can reveal drift, lag, or new failures after later source and deployment changes while analysts need low-latency aggregates refreshed on a defined cadence.
Incorrect Answers
A:Verify refresh applies new silver rows and queries return the expected totals is a one-time acceptance check. It does not supply continuing operational detection for claims_payment_events_delta; a passing test cannot substitute for the specific task now required.
B:Ordinary views do not persist precomputed results. The proposed action (Create a regular view and promise it stores its results between queries at Regional insurance broker) does not meet the requirement that analysts need low-latency aggregates refreshed on a defined cadence, nor does it constitute continuing operational detection.
D:Publish a materialized view for precomputed frequently queried aggregates is a plausible lasting design once chosen, but it does not perform continuing operational detection at this stage. In the claims_payment_events_delta scenario, the observed evidence is that SQL history shows expensive repeated aggregation on an otherwise stable reporting query; the requirement remains: analysts need low-latency aggregates refreshed on a defined cadence.