Senior Data Engineer

Production-grade data engineering skill for building scalable, reliable data systems.

Table of Contents

1. Trigger Phrases
2. Quick Start
3. Workflows
4. Architecture Decision Framework
5. Tech Stack
6. Reference Documentation
7. Troubleshooting

---

Trigger Phrases

Activate this skill when you see:

Pipeline Design:

• "Design a data pipeline for..."
• "Build an ETL/ELT process..."
• "How should I ingest data from..."
• "Set up data extraction from..."

Architecture:

• "Should I use batch or streaming?"
• "Lambda vs Kappa architecture"
• "How to handle late-arriving data"
• "Design a data lakehouse"

Data Modeling:

• "Create a dimensional model..."
• "Star schema vs snowflake"
• "Implement slowly changing dimensions"
• "Design a data vault"

Data Quality:

• "Add data validation to..."
• "Set up data quality checks"
• "Monitor data freshness"
• "Implement data contracts"

Performance:

• "Optimize this Spark job"
• "Query is running slow"
• "Reduce pipeline execution time"
• "Tune Airflow DAG"

---

Quick Start

Core Tools

# Generate pipeline orchestration config
python scripts/pipeline_orchestrator.py generate \
  --type airflow \
  --source postgres \
  --destination snowflake \
  --schedule "0 5 * * *"

# Validate data quality
python scripts/data_quality_validator.py validate \
  --input data/sales.parquet \
  --schema schemas/sales.json \
  --checks freshness,completeness,uniqueness

# Optimize ETL performance
python scripts/etl_performance_optimizer.py analyze \
  --query queries/daily_aggregation.sql \
  --engine spark \
  --recommend

---

Workflows

→ See references/workflows.md for details

Architecture Decision Framework

Use this framework to choose the right approach for your data pipeline.

Batch vs Streaming

Criteria	Batch	Streaming
Latency requirement	Hours to days	Seconds to minutes
Data volume	Large historical datasets	Continuous event streams
Processing complexity	Complex transformations, ML	Simple aggregations, filtering
Cost sensitivity	More cost-effective	Higher infrastructure cost
Error handling	Easier to reprocess	Requires careful design

Decision Tree:

Is real-time insight required?
├── Yes → Use streaming
│   └── Is exactly-once semantics needed?
│       ├── Yes → Kafka + Flink/Spark Structured Streaming
│       └── No → Kafka + consumer groups
└── No → Use batch
    └── Is data volume > 1TB daily?
        ├── Yes → Spark/Databricks
        └── No → dbt + warehouse compute

Lambda vs Kappa Architecture

Aspect	Lambda	Kappa
Complexity	Two codebases (batch + stream)	Single codebase
Maintenance	Higher (sync batch/stream logic)	Lower
Reprocessing	Native batch layer	Replay from source
Use case	ML training + real-time serving	Pure event-driven

When to choose Lambda:

• Need to train ML models on historical data
• Complex batch transformations not feasible in streaming
• Existing batch infrastructure

When to choose Kappa:

• Event-sourced architecture
• All processing can be expressed as stream operations
• Starting fresh without legacy systems

Data Warehouse vs Data Lakehouse

Feature	Warehouse (Snowflake/BigQuery)	Lakehouse (Delta/Iceberg)
Best for	BI, SQL analytics	ML, unstructured data
Storage cost	Higher (proprietary format)	Lower (open formats)
Flexibility	Schema-on-write	Schema-on-read
Performance	Excellent for SQL	Good, improving
Ecosystem	Mature BI tools	Growing ML tooling

---

Tech Stack

Category	Technologies
Languages	Python, SQL, Scala
Orchestration	Airflow, Prefect, Dagster
Transformation	dbt, Spark, Flink
Streaming	Kafka, Kinesis, Pub/Sub
Storage	S3, GCS, Delta Lake, Iceberg
Warehouses	Snowflake, BigQuery, Redshift, Databricks
Quality	Great Expectations, dbt tests, Monte Carlo
Monitoring	Prometheus, Grafana, Datadog

---

Reference Documentation

1. Data Pipeline Architecture

See references/data_pipeline_architecture.md for:

• Lambda vs Kappa architecture patterns
• Batch processing with Spark and Airflow
• Stream processing with Kafka and Flink
• Exactly-once semantics implementation
• Error handling and dead letter queues

2. Data Modeling Patterns

See references/data_modeling_patterns.md for:

• Dimensional modeling (Star/Snowflake)
• Slowly Changing Dimensions (SCD Types 1-6)
• Data Vault modeling
• dbt best practices
• Partitioning and clustering

3. DataOps Best Practices

See references/dataops_best_practices.md for:

• Data testing frameworks
• Data contracts and schema validation
• CI/CD for data pipelines
• Observability and lineage
• Incident response

---

Troubleshooting

→ See references/troubleshooting.md for details