Data Engineering & Analytics Infrastructure Topics
Data pipeline design, ETL/ELT processes, streaming architectures, data warehousing infrastructure, analytics platform design, and real-time data processing. Covers event-driven systems, batch and streaming trade-offs, data quality and governance at scale, schema design for analytics, and infrastructure for big data processing. Distinct from Data Science & Analytics (which focuses on statistical analysis and insights) and from Cloud & Infrastructure (platform-focused rather than data-flow focused).
Data Cleaning and Quality Validation in SQL
Handle NULL values, duplicates, and data type issues within queries. Implement data validation checks (row counts, value distributions, date ranges). Practice identifying and documenting data quality issues that impact analysis reliability.
Stream Processing and Event Streaming
Designing and operating systems that ingest, process, and serve continuous event streams with low latency and high throughput. Core areas include architecture patterns for stream native and event driven systems, trade offs between batch and streaming models, and event sourcing concepts. Candidates should demonstrate knowledge of messaging and ingestion layers, message brokers and commit log systems, partitioning and consumer group patterns, partition key selection, ordering guarantees, retention and compaction strategies, and deduplication techniques. Processing concerns include stream processing engines, state stores, stateful processing, checkpointing and fault recovery, processing guarantees such as at least once and exactly once semantics, idempotence, and time semantics including event time versus processing time, watermarks, windowing strategies, late and out of order event handling, and stream to stream and stream to table joins and aggregations over windows. Performance and operational topics cover partitioning and scaling strategies, backpressure and flow control, latency versus throughput trade offs, resource isolation, monitoring and alerting, testing strategies for streaming pipelines, schema evolution and compatibility, idempotent sinks, persistent storage choices for state and checkpoints, and operational metrics such as stream lag. Familiarity with concrete technologies and frameworks is expected when discussing designs and trade offs, for example Apache Kafka, Kafka Streams, Apache Flink, Spark Structured Streaming, Amazon Kinesis, and common serialization formats such as Avro, Protocol Buffers, and JSON.
Analytics Architecture and Reporting
Designing and operating end to end analytics and reporting platforms that translate business requirements into reliable and actionable insights. This includes defining metrics and key performance indicators for different audiences, instrumentation and event design for accurate measurement, data ingestion and transformation pipelines, and data warehouse and storage architecture choices. Candidates should be able to discuss data modeling for analytics including semantic layers and data marts, approaches to ensure metric consistency across tools such as a single source of truth or metric registry, and trade offs between query performance and freshness including batch versus streaming approaches. The topic also covers dashboard architecture and visualization best practices, precomputation and aggregation strategies for performance, self service analytics enablement and adoption, support for ad hoc analysis and real time reporting, plus access controls, data governance, monitoring, data quality controls, and operational practices for scaling, maintainability, and incident detection and resolution. Interviewers will probe end to end implementations, how monitoring and quality controls were applied, and how stakeholder needs were balanced with platform constraints.
Data Warehousing and Data Lakes
Covers conceptual and practical design, architecture, and operational considerations for data warehouses and data lakes. Topics include differences between warehouses and lakes, staging areas and ingestion patterns, schema design such as star schema and dimensional modeling, handling slowly changing dimensions and fact tables, partitioning and bucketing strategies for large datasets, common architectures including medallion architecture with bronze silver and gold layers, real time and batch ingestion approaches, metadata management, and data governance. Interview questions may probe trade offs between architectures, how to design schemas for analytical queries, how to support both analytical performance and flexibility, and how to incorporate lineage and governance into designs.
Automated Reporting & Report Development
Build automated reports that refresh on schedule. Understand refresh schedules, data pipeline integration, and deployment to production. Create parameterized reports for different stakeholder needs. Know how to version control and manage report changes.
Data Transformation and Loading
Focuses on the extract transform load and extract load transform approaches for ingesting transforming and loading data. Candidates should understand three core stages: extract which is acquiring data from sources such as application programming interfaces databases logs and message queues; transform which is cleaning validating reshaping aggregating and enriching data to meet downstream requirements; and load which is writing processed data to targets such as analytic databases data warehouses data lakes or reporting systems. Topics include the differences between extract transform load and extract load transform, incremental loads versus full refresh, scheduling and orchestration best practices, tooling and frameworks used for transformation and orchestration, idempotency and deduplication strategies, error handling and retry semantics, data quality checks end to end validation recovery and integration with business intelligence and analytics consumers. Interview focus is on concrete transformation logic pipeline orchestration and validation strategies and on choosing the right pattern and tooling for given constraints.
Dimensional Modeling and Star Schema Concepts
Understand fact and dimension tables, surrogate keys, and slowly changing dimensions. Be able to write queries that efficiently query dimensional data structures. Understand grain of fact tables and how to aggregate appropriately.
Business Intelligence and Analytics Performance
Performance considerations for business intelligence and analytics tools and pipelines. Topics include extract versus live connections, incremental refresh strategies, aggregated tables and precomputation, dashboard profiling, minimizing visual complexity, and caching strategies for reporting layers. Candidates should understand when to denormalize data for reporting, how to monitor query times inside BI tools, and trade offs between real time versus pre aggregated reporting.
Data Quality and Anomaly Detection
Focuses on identifying, diagnosing, and preventing data issues that produce misleading or incorrect metrics. Topics include spotting duplicates, missing values, schema drift, logical inconsistencies, extreme outliers caused by instrumentation bugs, data latency and pipeline failures, and reconciliation differences between sources. Covers validation strategies such as data tests, checksums, row counts, data contracts, invariants, and automated alerting for quality metrics like completeness, accuracy, and timeliness. Also addresses investigation workflows to determine whether anomalies are data problems versus true business signals, documenting remediation steps, and collaborating with engineering and product teams to fix upstream causes.