Data Engineering
Data Pipeline Patterns
Batch Processing
- •Scheduled Jobs: Run data processing at fixed intervals (hourly, daily, weekly)
- •Use Cases: Historical analysis, reporting, data warehousing
- •Tools: Apache Spark, Hadoop, Airflow, dbt
- •Design Considerations: Latency tolerance, resource efficiency, cost optimization
Streaming Processing
- •Real-time Ingestion: Process data as it arrives with low latency
- •Use Cases: Real-time analytics, monitoring, fraud detection
- •Tools: Apache Kafka, Apache Flink, Apache Storm, Apache Beam
- •Design Considerations: Event ordering, exactly-once semantics, backpressure
Lambda Architecture
- •Batch Layer: Store immutable master dataset, compute batch views
- •Speed Layer: Process real-time data for low-latency queries
- •Serving Layer: Merge batch and real-time views for queries
- •Use Cases: Systems requiring both batch and real-time capabilities
- •Challenges: Complexity of maintaining two code paths
Kappa Architecture
- •Unified Processing: Use a single stream processing framework
- •Replay Capability: Reprocess data from the event log
- •Use Cases: Simplified architecture when batch is just fast streaming
- •Benefits: Reduced complexity, single codebase
ETL/ELT Best Practices
ETL (Extract, Transform, Load)
- •Extract: Pull data from source systems with minimal impact
- •Transform: Clean, validate, and transform data in a staging area
- •Load: Load processed data into the target system
- •Best Practices:
- •Minimize source system impact
- •Handle incremental updates efficiently
- •Validate data before loading
- •Document transformation logic
ELT (Extract, Load, Transform)
- •Extract: Pull raw data from source systems
- •Load: Load raw data into the target system (usually data warehouse)
- •Transform: Transform data within the target system using SQL
- •Best Practices:
- •Leverage data warehouse compute power
- •Maintain raw data for audit trails
- •Use dbt for transformation orchestration
- •Version control transformation logic
Data Ingestion Patterns
- •Full Load: Load entire dataset each time
- •Incremental Load: Load only changed records
- •Change Data Capture (CDC): Capture data changes in real-time
- •Bulk Load: High-volume batch loading for initial loads
Data Storage Options
SQL Databases
- •Relational Data: Structured data with relationships
- •ACID Compliance: Strong consistency guarantees
- •Examples: PostgreSQL, MySQL, SQL Server, Oracle
- •Use Cases: Transactional systems, operational data stores
NoSQL Databases
- •Document Stores: JSON-like documents (MongoDB, CouchDB)
- •Key-Value Stores: Simple key-value pairs (Redis, DynamoDB)
- •Column-Family Stores: Wide-column storage (Cassandra, HBase)
- •Graph Databases: Relationship-focused (Neo4j, Amazon Neptune)
- •Use Cases: Semi-structured data, high scalability, specific data models
Data Lakes
- •Raw Data Storage: Store data in native format
- •Schema-on-Read: Define schema when reading data
- •Examples: AWS S3, Azure Data Lake, Google Cloud Storage
- •Use Cases: Data exploration, ML training, archiving
Data Warehouses
- •Optimized for Analytics: Columnar storage, compression
- •SQL Interface: Familiar query language
- •Examples: Snowflake, BigQuery, Redshift, Azure Synapse
- •Use Cases: Business intelligence, reporting, analytics
Data Quality and Validation
Data Quality Dimensions
- •Completeness: No missing values or records
- •Accuracy: Data reflects real-world values
- •Consistency: No conflicting data across sources
- •Timeliness: Data is up-to-date
- •Validity: Data conforms to defined rules and formats
- •Uniqueness: No duplicate records
Validation Techniques
- •Schema Validation: Check data types, formats, and constraints
- •Range Checks: Verify values fall within expected ranges
- •Pattern Matching: Use regex for format validation (email, phone, etc.)
- •Referential Integrity: Validate foreign key relationships
- •Business Rules: Apply domain-specific validation logic
Data Profiling
- •Statistical Analysis: Understand data distributions and patterns
- •Pattern Discovery: Identify data formats and structures
- •Anomaly Detection: Find outliers and unusual values
- •Dependency Analysis: Discover relationships between fields
Data Lineage
- •Source Tracking: Trace data back to original sources
- •Transformation Tracking: Document all transformations applied
- •Impact Analysis: Understand downstream effects of changes
- •Compliance: Meet regulatory requirements for data tracking