Every Android developer has been there: a crash report full of a.b.c() and x.y.z() - completely useless without a R8/ProGuard mapping file. At Sentry, we ingest over 3 billion Android crash events per month, and getting deobfuscation right matters a lot.

This talk tells the story of a production incident that forced us to rethink how R8/ProGuard deobfuscation works at scale - from loading entire mapping files into memory (sometimes hundreds of megabytes each) to a new on-disk cache format that serves 99% of deobfuscation requests without ever touching the original file.

The result: 88% latency reduction and a 20x throughput improvement.

We'll cover the architecture of the R8/ProGuard cache format, and what it actually looks like to ship low-level symbolication infrastructure at this scale.

If you've ever wondered what happens to your mapping file after you hit upload - this is the talk for you.