Before submitting for review, we need to ensure the implementation is fully tested, passes all existing tests, and meets the epic's acceptance criteria (O(log n) search, all tests pass, production quality).

Tasks

• build/ — Run full Catch2 test suite: ./test/catch2/catch2-unittests (criterion: all tests pass)
• build/ — Run compaction test suite: python3 ../test/suite/run.py test_compact* (criterion: all compaction tests pass)
• build/ — Run dist/s_all to validate code style, prototypes, and generated code (criterion: s_all passes with no errors)
• src/block/block_ext.c — Add or update statistics: keep block_ext_walked stat from prototype, ensure it's correctly tracked by __block_first_srch_v2 (criterion: stat tracks number of skiplist nodes examined during search)
• Performance validation — Run a compaction workload (e.g., test/format with compaction enabled, or manual compact on a large database with many holes) and verify via statistics that block_ext_walked is low (criterion: block_ext_walked averages < 20 per search in a workload with 1000+ holes, demonstrating O(log n) behavior)

Files to create or modify

• src/block/block_ext.c — final implementation
• dist/stat_data.py — statistics definitions
• build/ — test execution
• test/suite/test_compact*.py — compaction tests
• test/catch2/block/ — unit tests

Definition of Done

• All existing tests pass (Catch2, compaction suite, dist/s_all)
• Statistics demonstrate O(log n) search performance
• Code is production-ready: no known bugs, fully documented, style-compliant
• Epic acceptance criteria met: O(log n) search, all tests pass, production quality