agent.md

Engineering Conventions for BPlusTree3

• No feature flags for internal experiments. We have no external users, so avoid #[cfg(feature = ...)] branches. Implement improvements directly (or in short‑lived local branches) and remove experimental code before merging.

• Performance work

  • Validate with existing Criterion benches and the large delete runner (rust/src/bin/large_delete_benchmark.rs).
  • For line‑level CPU hotspots, use the Instruments workload (rust/src/bin/instruments_delete_target.rs) and store traces under rust/delete_profile.trace (not committed).
  • Prefer targeted, localized changes that don’t regress insert/get/range performance.

• Coding style

  • Keep changes minimal and focused on the stated goal.
  • Reduce repeated arena lookups and redundant separator/key reads in hot paths.
  • Favor bulk moves and pre‑allocation over per‑element operations.

• Benchmarks to run for delete changes

  • cd rust && cargo bench --bench comparison deletion
  • cd rust && cargo run --release --bin large_delete_benchmark
  • Optional: record Instruments trace for confirmation of hotspot reductions.

• Hygiene before commit

  • Always remove dead code introduced by refactors.
  • Delete code as soon as it is dead.
  • Always format the workspace: cd rust && cargo fmt --all.
  • Always run all tests: cargo test --workspace (and benches if relevant).