Practical Database Engineering
Database Troubleshooting, Performance, and AI Search Guides
Hands-on guides for SQL Server, PostgreSQL, Oracle, MySQL, DuckDB, MongoDB, Redis, and SQLite. Find reproducible fixes, tested SQL, upgrade checklists, and architecture decisions written for working DBAs and developers.
Learn Database: choose your next step
Select Database Product
SQL Server
Installation, HA/DR, Tuning
PostgreSQL
Tutorials, Operations, Tuning
Oracle Database
Architecture, Ops, Tuning
MySQL
Replication, Backup, Tuning
DuckDB
Analytics, Parquet, Embedded SQL
MongoDB
Documents, Search, Vector
Redis
Caching, Streams, Vector
SQLite
Embedded Apps, WAL, SQL
Popular DBA Guides
SQL Server · Concurrency
Transaction Isolation Levels Explained
Read Committed, Snapshot, and RCSI with practical blocking behavior.
SQL Server · Performance
Nested Loops, Hash Join, and Merge Join
Read join operators and understand why the optimizer chose them.
SQL Server · Monitoring
Essential DMV Queries
A practical starting set for active requests, waits, I/O, and plans.
SQL Server · Security
Row-Level Security Step by Step
Implement and verify predicate-based access control.
SQL Server · Troubleshooting
Fix “The Target Principal Name Is Incorrect”
A certificate and SPN workflow for connection failures.
DuckDB · Analytics
Analyze CSV and Parquet With SQL
Start local analytical queries without building a server first.