# index-db -- Roadmap
> Path from scaffold to a stable 1.0. Hard parts are front-loaded; each phase has hard exit criteria.
>
> **Anti-deferral rule:** no listed hard task moves to a later phase unless this file records the move and the reason.
---
## v0.1.0 -- Scaffold (DONE)
Compiles, CI green, structure correct, no domain logic.
- [x] Manifest, README, CHANGELOG, REPS, dual license, CI, deny, clippy, rustfmt, FUNDING.
- [x] API surface sketched in `docs/API.md`.
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## v0.2.0 -- B+tree core over pages: search / insert / node split (THE HARD PART, NOT DEFERRED) (DONE)
`BPlusTree<K, V>` with `new`/`insert`/`get`/`contains_key`/`len`/`is_empty`/`height`/`clear`.
Automatic leaf + internal split with median promotion; balanced at every depth.
Heap-backed nodes for now (page-db is unpublished and carries no path dep); the
node layout is the page-oriented one a pager will persist later.
Exit criteria:
- [x] Every public item has rustdoc + a runnable example.
- [x] Core invariants property-tested (balance, sorted keys, separators; cross-checked vs `BTreeMap`).
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## v0.3.0 -- delete + merge/redistribute + forward & reverse range scans (DONE)
`remove` with sibling borrow / merge and root collapse; `iter`/`range` as a
double-ended iterator (`Iter`) over `(&K, &V)`, plus `IntoIterator for &tree`.
Routing-separator + minimum-occupancy invariants property-tested after every
delete; iteration/range cross-checked vs `BTreeMap` forward and reverse.
Exit criteria:
- [x] New surface tested; hot paths benchmarked (range scan + bulk remove).
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## v0.4.0 -- concurrent access via latch coupling + bulk load + feature freeze
Exit criteria:
- [ ] No `todo!`/`unimplemented!`. Feature freeze declared.
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## v0.5.0 -- adversarial key distributions + concurrent-traversal stress + API freeze
Exit criteria:
- [ ] Public API frozen (recorded here). `cargo audit` + `cargo deny` clean.
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## v0.6.0 -> v1.0.0 -- Alpha / Beta / RC / Stable
Integrate against real consumers, broaden testing, capture final benchmarks, then freeze the public API until 2.0 and publish.
---
## Out of scope for 1.0
- The page store itself - `page-db` owns pages and caching.
- Locking - `lock-db` owns concurrency control; index-db uses latches only for tree structure.
- LSM / column storage - different engines (`lsm-db`, CORD).