NotesEngineering notesWriting on software architecture, backend systems, developer tooling, and AI-assisted workflows.Allaibackendcachingcareerci cdconcurrencydatabasedeveloper experiencedevopsgithub actionsgoopen sourceperformancepostgresqlsoftware architecturesystem designtestingworkflowSearchClear filtersN-001September 24, 2026The Query Got Faster—and the Result Became WrongA real PostgreSQL case where a convincing EXPLAIN ANALYZE led to a faster rewrite that silently changed the result—and what I now validate before accepting a query optimization.database / performance / postgresql / testing9 min read