seek

Now: DONT

kv64 (dog/abc/KV.h: (u64 key, u64 val), KEY-ONLY Z/hashEq) is already registered in jab's container bindings — HEAP_REG/ HASH_REG/HIT_REG(kv64) (heap.hpp, hash.hpp, hit.hpp) — but the LSM surface abc.index serves only u64 and wh128: kv64 is explicitly DEFERRED (index.hpp ~~28, API.md~~ 396) because compaction and .seek dedup are FULL-ELEMENT newest-wins, which a key-only comparator breaks. Build the keyed variant: one live val per key, newest wins, older same-key rows collapse. This is the true-map twin of wh128's multimap — the LWW lane ANNO-001's status atoms want.

Input

Context

kv64Z compares keys only, so same-key rows are Z-equal ties; the HIT ladder's "newest in the stream wins on a tie" already picks a winner — it just doesn't DROP the losers (full-element dedup).
Query today: get scans runs newest-first (shadowing at query time); .seek merges via a min-heap with full-element dedup — both are one keyed-equality rule away from map semantics.
v1 deletes (API.md): a newer run shadows an older at query time, compaction never drops — the tombstone mechanism is being ruled in ANNO-001 TODO-1 (negative runs vs sidecar mask).
ANNO-001's multimap rides wh128 (full-pair Z); single-val-per- key annos (a ticket's ONE status atom, LWW) fit a keyed lane.
TODO-003 is the second driver: its board query Sta: OPEN streams a prefix block, and with overwrites never collapsed it returns every ticket EVER opened — i.e. all of them.
kv64 and wh128 are byte-identical 16-byte pairs (KV.h:19, WHIFF.h:53) differing only in Z/hashEq, so an existing wh128 run re-reads as kv64 — adopting the lane costs no data migration.

Goals

abc.index kv64 lane: put/get/range/seek returning ONE live val per key (newest wins); keyed compaction collapses shadowed rows.
Same run/mmap machinery: ron60 run names, alignment check, idxmaint-style ladder — a lane, not a fork.
Query-time overwrite collapse on .range/.prefix too, not just get/seek: the streaming fast-drain is the board's query shape and today it deliberately skips cross-run dedup.

Constraints

wh128 and u64 lane behavior stays byte-identical; keyed dedup is a per-lane property, never a global switch.
Rule #4: all state in JS, native leaves are marshalling only; extend HITx.h with a keyed-collapse variant, no second LSM impl.
Don't paint the tombstone ruling into a corner: a keyed lane makes key-wide kills natural (newest tombstone per key wins, evaporates at the bottom run) — keep the merge shaped for that.

WIP

Design decisions

Keyed collapse = dedup on Z-equality instead of full-element equality; kv64Z's key-only ordering makes same-key rows adjacent in the merge, so the collapse is a comparator swap, not new flow.
Memtable put replaces the same key (HASHkv64 exists); get = per-run sFindGE newest-first, first hit wins — today's shadowing shape, now also the compaction rule.

TODOs

1. Table-driven C tests FIRST for the keyed HITkv64Compact: same-key rows across runs (newest wins), ties inside one run, torn/misaligned run rejection.
2. HITx.h keyed-collapse variant instantiated for kv64; prove wh128/u64 ladders unchanged (existing tests stay green).
3. index.hpp: wire the kv64 lane — put crosses (key,val) as two BigInts, get/needles/lo/hi as the key BigInt, val returned; per-run alignment check (16-byte slot, same as wh128).
4. JS surface: abc.index({lane:'kv64'}) put/get/range/seek; seek exposes .key/.val/.entry like the wh128 lane.
4b. Query-time collapse for .range/.prefix on the keyed lane: keyed dedup in the seekrange drain, newest run wins; test a key overwritten in a younger run AND within one run.
5. Maintenance: generalize idxmaint.js (EXT/SLOT/lane param) or add the kv64 twin; ladder-compaction test through JS.
6. Docs: API.md kv64 section (deferral note removed), jab INDEX.md; note the lane choice rule (map=kv64, multimap=wh128).
7. Deletes: adopt the tombstone mechanism once ANNO-001 TODO-1 is ruled; key-wide kill = newest-tombstone-per-key, dropped when the merge reaches the bottom run.

Blockers and bummers

Only TODO-7 is gated (the tombstone ruling); 1–6 are unblocked.
Run-age ordering is load-bearing for keyed ties: the ladder must keep the oldest-first stack invariant or LWW silently inverts.

Outcome

Open. Filed 2026-07-24, split from the ANNO-001 design chat (kv64 deferral found while checking jab index lanes).