Tell us about your cases of detecting and fixing bugs in complex distributed systems

In complex distributed systems, bugs often manifest due to network delays, component desynchronization, or errors in interaction logic. To detect them, I used the following approaches:

• Logging with unique request identifiers to track data flow through the system.
• Using tracing and monitoring tools, such as OpenTelemetry or Zipkin.
• Reproducing the problem in a test environment with similar load.
• Analyzing memory dumps and core files during crashes.

To fix bugs, it is important to understand at which stage the error occurs — in communication, data processing, or synchronization. For example, I once discovered a data race between threads that led to an incorrect state. The solution was to introduce mutexes and atomic operations to protect shared resources.

This systematic approach helps identify and eliminate complex errors in distributed systems.