Databases & Data

Expertise in relational databases, distributed systems, and data architecture

Relational Databases

PostgreSQL

  • Proficiency: Advanced

  • Key Skills:

    • Database design and normalization
    • Complex queries and joins
    • Indexing strategies
    • Query optimization and EXPLAIN ANALYZE
    • Transaction management
    • ACID compliance
    • Window functions
    • Common Table Expressions (CTEs)
    • JSON/JSONB support
    • Full-text search

  • Administration:

    • User and role management
    • Backup and restore (pg_dump, pg_restore)
    • Replication and failover
    • Extensions (PostGIS, pgvector, etc.)
    • Performance tuning
    • Monitoring and statistics

  • Projects: Personal Finance Manager (planned), HAY platform, homelab services

  • Strengths: Robustness, advanced features, excellent documentation

SQLite

  • Proficiency: Intermediate
  • Use Cases: Development, embedded databases, small projects
  • Key Skills:
    • Schema design
    • SQL queries
    • Performance considerations
    • File management
    • Limitations and workarounds

NoSQL Databases

Document Databases

  • Basic understanding of MongoDB
  • JSON document storage concepts
  • Schema-less design

Distributed Data Systems

Kafka (Event Streaming)

  • Proficiency: Intermediate

  • Key Skills:

    • Topic creation and management
    • Producer/Consumer concepts
    • Partition strategies
    • Offset management
    • Consumer groups
    • Replication factor
    • Event schema design
    • Avro/Protobuf serialization

  • Use Cases:

    • Asynchronous processing
    • Event sourcing
    • Microservice communication
    • Stream processing
    • Data pipelines

  • Projects: Personal Finance Manager (planned), homelab dev stack

Ceph Distributed Storage

  • Proficiency: Intermediate

  • Key Skills:

    • Object Storage (RADOS)
    • Block Storage (RBD)
    • File Storage (CephFS)
    • Monitor architecture
    • OSD management
    • Data placement and replication
    • Health monitoring
    • Scaling

  • Projects: Proxmox homelab cluster storage

Message Queues

RabbitMQ

  • Proficiency: Basic-Intermediate

  • Concepts:

    • Exchanges and routing
    • Queues and consumers
    • Dead-letter queues
    • Message persistence
    • TTL (Time To Live)
    • Priority queues

  • Use Cases: Task queues, async processing, microservice communication

SQL Skills

Query Design

  • SELECT queries: Projections, filtering, ordering
  • JOINs: INNER, LEFT, RIGHT, FULL OUTER
  • Aggregations: GROUP BY, HAVING, window functions
  • Subqueries: Correlated and uncorrelated
  • CTEs: Common Table Expressions for complex logic
  • UNION/UNION ALL: Combining result sets

Advanced SQL

  • Window Functions: ROW_NUMBER, RANK, DENSE_RANK, LAG/LEAD
  • JSON Operations: JSON creation, extraction, modification
  • Full-Text Search: Text indexing and search
  • Array Operations: ARRAY types and functions
  • Recursive Queries: WITH RECURSIVE

Performance Optimization

  • Indexing Strategies:

    • B-tree indexes
    • Hash indexes
    • Partial indexes
    • Composite indexes
    • BRIN indexes

  • Query Analysis:

    • EXPLAIN ANALYZE
    • Query plans
    • Sequential vs. index scans
    • Nested loop vs. hash joins

  • Optimization Techniques:

    • Avoiding full table scans
    • Index selectivity
    • Query rewriting
    • Statistics and ANALYZE
    • Vacuum and maintenance

Schema Design

Normalization

  • First Normal Form (1NF)
  • Second Normal Form (2NF)
  • Third Normal Form (3NF)
  • Boyce-Codd Normal Form (BCNF)
  • Denormalization trade-offs

Relationship Design

  • One-to-Many relationships
  • Many-to-Many with junction tables
  • Self-referencing relationships
  • Soft deletes vs. hard deletes
  • Foreign key constraints

Data Types

  • Numeric: INT, BIGINT, DECIMAL, NUMERIC
  • Text: VARCHAR, TEXT, CHAR
  • Date/Time: DATE, TIME, TIMESTAMP
  • Boolean: BOOL
  • Arrays: ARRAY types
  • JSON: JSONB for flexibility
  • Enums: Custom enumerated types

Data Migration

Data Import/Export

  • CSV import/export
  • Bulk loading
  • ETL processes
  • Data transformation
  • Validation and error handling

Schema Migrations

  • DDL statements
  • Non-blocking schema changes
  • Backwards compatibility
  • Rollback strategies
  • Zero-downtime deployments

Backup & Recovery

Backup Strategies

  • Full backups
  • Incremental backups
  • Point-in-time recovery (PITR)
  • WAL (Write-Ahead Logging)
  • Continuous replication

Disaster Recovery

  • RTO (Recovery Time Objective)
  • RPO (Recovery Point Objective)
  • Failover procedures
  • Testing recovery plans

Caching

In-Memory Caching

  • Redis basics
  • Cache invalidation strategies
  • TTL management
  • Cache-aside pattern
  • Write-through caching

Query Caching

  • Application-level caching
  • Materialized views
  • Query result caching

Replication & Failover

Replication Strategies

  • Streaming replication
  • Logical replication
  • Multi-master replication
  • Consistency considerations

High Availability

  • Primary/Standby setup
  • Automatic failover
  • Load balancing
  • Synchronous vs. asynchronous replication

ORMs & Data Abstraction

SQLAlchemy (Python)

  • Model definition
  • Session management
  • Query API
  • Relationships and joins
  • Lazy vs. eager loading
  • Custom types

Micronaut Data (Java)

  • Compile-time query generation
  • Annotation-based configuration
  • Repository pattern
  • Custom queries
  • Performance optimization

Monitoring & Observability

Database Monitoring

  • Query performance
  • Slow query logs
  • Connection pool health
  • Disk usage
  • Transaction rates
  • Lock monitoring
  • Replication lag

Tools

  • Prometheus PostgreSQL exporter
  • Grafana dashboards
  • pgBadger for log analysis
  • pg_stat views

Data Privacy & Security

Security Considerations

  • User authentication
  • Role-based access control (RBAC)
  • Column-level encryption
  • Row-level security (RLS)
  • Audit logging
  • Secrets management

Compliance

  • Data retention policies
  • GDPR compliance
  • Encryption at rest
  • Encryption in transit
  • PII handling

JSON & Semi-Structured Data

JSONB in PostgreSQL

  • JSON storage and querying
  • GIN indexes for JSON
  • @>, @, ? operators
  • jsonb_extract functions
  • JSON schema validation

Time-Series Data

Concepts

  • Time-series storage
  • Compression
  • Retention policies
  • Downsampling
  • Aggregation

InfluxDB (Basic)

  • Time-series database
  • Retention policies
  • Continuous queries

Best Practices

  • Meaningful column names
  • Consistent data types
  • Proper indexing
  • Regular backups
  • Monitoring in production
  • Query optimization before scaling
  • Documentation
  • Version control for schema
  • Testing data migrations