Debugging complex issues in web applications

on YouTube ↗50m

" summary

Reproduces two real Tomcat bugs and shows concrete fixes and workarounds: a reproducible HTTP/2 semaphore deadlock triggered by three+ multi-GB concurrent streams where a race clears the stream’s operation state before releasing the semaphore — fix is to swap clearing and release and validate with repeated runs; and an intermittent missing-response caused by a native PDFTron library closing file descriptors twice, diagnosed with strace + Wireshark and resolved by disabling the library or using HTTP/1.1. Uses debug logging, thread dumps, rolling logs and a practical 20-test rule for statistical confidence.

AI-written summary · about

" chapters (8)

1. 0:00Introduction
2. 2:20What makes issues complex
3. 5:53Debugging methodology
4. 10:49HTTP/2 response blocking issue
5. 22:57Premature connection drops
6. 37:25Debugging techniques
7. 43:19Handling vendor bugs
8. 47:53Q&A

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