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Data Engineer Mid Interview Questions

503 verified Data Engineer Mid interview questions — solve with answers, learn from explanations, test yourself in a real simulation.

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Sample questions

Data Governance LineageDifficulty 2
A dashboard metric suddenly shows an unexpected drop. Before touching any code, what is the most useful first step that lineage information enables?
  • aIncreasing the retry count of the job that produces the dashboard
  • bAsking the dashboard's end users to describe what they expected to see
  • cRestarting the entire data platform to clear any cached state
  • dTracing the metric backward through lineage to the changed source✓
Explanation:Lineage lets an engineer trace the metric backward to the exact upstream source or transformation that changed, instead of guessing via retries or restarts.
Data Governance LineageDifficulty 2
A team plans to drop a column from a shared table. What should they check first to avoid breaking anything?
  • aWhether the column name is spelled consistently across the codebase
  • bHow much disk space the column currently occupies
  • cThe lineage graph, to see which downstream consumers use it✓
  • dThe color scheme used in dashboards that display the table
Explanation:The lineage graph shows exactly which downstream reports and pipelines depend on that column, so the team can assess the real impact before dropping it.
Data Governance LineageDifficulty 2
Why is column-level lineage generally more useful than table-level lineage for impact analysis?
  • aIt requires less metadata to maintain overall
  • bIt shows exactly which downstream fields depend on that column✓
  • cIt automatically fixes broken pipelines without manual intervention
  • dIt removes the need for a data catalog entirely
Explanation:Column-level lineage pinpoints which specific downstream fields are affected, avoiding wasted effort investigating unrelated parts of a table.
Data Governance LineageDifficulty 2
Before renaming a widely-used table, an engineer wants to know exactly which reports would break. Lineage tracking helps by...
  • aAutomatically renaming the table in every downstream system
  • bNotifying all employees in the company by broadcast email
  • cEncrypting the table so unauthorized changes are prevented
  • dListing every downstream consumer of that table✓
Explanation:Lineage tracking lists every downstream consumer of a table, so each one can be reviewed or updated before a breaking change like a rename.
Data Governance LineageDifficulty 2
A team documents a table in the data catalog using an entry like the one below.
dataset: orders
owner: sales-team
classification: internal
description: one row per completed order
last_updated: daily

What is the main benefit of maintaining entries like this?
  • aPeople can quickly find, understand, and know who owns the data✓
  • bThe entry automatically enforces access permissions on the underlying table
  • cThe entry replaces the need for any data quality checks on the table
  • dThe entry increases the query performance of the orders table
Explanation:Catalog entries like this let people discover the dataset, understand its meaning, and know who owns it, without needing to ask around.
Data Governance LineageDifficulty 2
A new analyst joins the team and needs to find a table that has revenue by region. There is no catalog. What is the most likely consequence?
  • aThe analyst will automatically be granted access to all tables
  • bThe analyst wastes time asking around instead✓
  • cThe database will reject queries from new employees
  • dThe lack of a catalog will improve query performance
Explanation:Without a catalog, discovering existing data relies on informal channels, which wastes time and risks duplicated or forgotten datasets.

Topics

Data Governance Lineage 75Data Modeling Warehousing 75Data Partitioning Scaling 75Data Pipeline Design 75Data Pipeline Orchestration 75Data Pipeline Reliability 75Data Quality Validation 75Streaming Fundamentals 75

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