SEV · Data corruption
400K corrupted payment records
Payment data corruption hit 400K records in production. Working alongside dev on root cause, I identified ten distinct corruption patterns from the audit logs, translated them into 100 targeted test cases, and validated the fix end to end.
✓ shipped in 5 days · 0 critical defects post-release
Migration
Informix → PostgreSQL, 700M+ records
Owned test coverage across a full database engine migration. Ran 6 pre-production validation cycles covering 600M records before cutover.
✓ zero rollback
SEV · Data integrity
Serial number duplication
~2,000 records/day were silently duplicating serial numbers. Designed 55 test cases around the duplication surface and drove verification through a ~1.5-month fix cycle.
✓ duplication eliminated at source
Shift-left catch
Design flaw caught at 75% build
Spotted a fundamental design flaw in a data format feature on domain knowledge alone - before it ever reached production. Feature was disabled with zero production exposure.
✓ 0 customer impact · caught pre-release