I gave this talk at DevOpsDays Tel Aviv 2025.

Most systems rely on default configuration values, and that’s usually fine. But these defaults often go untouched for years, even when they no longer match the system’s scale or behavior. The result? Silent performance losses that are easy to miss and hard to trace.

In this talk, I share the true story of how changing a single digit in an obscure timeout setting cut our API latency in half. The issue wasn’t bad code, it was an outdated assumption baked into a default value that didn’t fit our system anymore.

You’ll learn:

• How configuration defaults can quietly create performance bottlenecks
• What invisible inefficiencies look like in advanced DB connection management (e.g. sharding, connection pools, connection multiplexers)
• How to detect these issues in production systems, even when logs and metrics seem fine
• A practical approach for evaluating, tuning, and monitoring configuration selection

This talk is for anyone working at the intersection of development and operations. If your systems are “working” but not performing, this will help you uncover why, and what to do next.