When Everything Works Correctly — and the System Still Fails

"Large Drupal platforms often fail not because of a single bug or poorly written module, but due to the accumulation of individually correct architectural decisions interacting in unexpected ways.

This talk presents a real-world technical assessment of a high-traffic Drupal system, where severe performance and stability issues emerged from tight coupling between data synchronization processes, editorial workflows, caching strategies, and synchronous side effects — all while following established Drupal patterns and widely accepted best practices.

We will examine how patterns such as recurring data imports, synchronous external integrations on content save, aggressive cache invalidation, role-based cache fragmentation, and heavily duplicated Views configurations combined to produce cache stampedes, database contention, and highly variable editor and user experience. Crucially, none of these problems were caused by “bad code” in isolation — the failure emerged from the interaction of correct components under real traffic and concurrency.

The session focuses on recognizing systemic risk patterns early, understanding why traditional “fix the slow query” or “add more caching” approaches often fail, and identifying architectural pressure points where relatively small changes can significantly improve system stability and predictability without requiring a full rewrite.

This talk is aimed at developers and technical leads working on medium- to large-scale Drupal platforms who want to move beyond cargo-culted best practices and design systems that behave reliably under real editorial and traffic conditions."