perf(delete): drop per-key B-tree probe & bulk-delete PK on the FW contiguous path (M3) - #382
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…ntiguous path The shared B8/B9 contiguous probe resolved every key with one Index.Search and then TryBulkDeleteContiguousFixedWidth removed the PK entries one Delete at a time — ~20K B-tree operations per 10K-row fixed-width batch. The probe now locates only the FIRST key through the tree, computes the remaining positions by the fixed-width stride, reads the contiguous span once and verifies every record by its length prefix AND its decoded fixed-width PK slot (equal to the batch key); the delete removes the PK entries with one DeleteBulk pass. The verification rejects exactly the batches the old per-key search rejected gaps/tombstones surface as prefix mismatches, a differing PK falls back like a tree miss), so nothing is modified before the whole span is proven valid. Fair-PK median-of-3 (sequential, uncontended): fixed-width UPDATE ~245K, DELETE ~172K ops/s vs ~138-164K/~120-156K in the earlier single-shot runs.
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Samenvatting
FW contigu pad (B8/B9): per-key B-tree probe vervangen door decode-verificatie +
DeleteBulk.De gedeelde contiguous-probe resolved elke key met één
Index.Search(~10K searches per10K-row batch) en de FW-DELETE verwijderde de PK-entry's daarna één
Deleteper key — samen~20K boomoperaties per batch. Nu:
PK-slot (gelijk aan de batch-key) — dezelfde batches vallen terug als voorheen (gaps/tombstones
→ prefix-mismatch; afwijkende PK → fallback), en er wordt niets gemuteerd vóór de hele span
bewezen geldig is;
DeleteBulk.Metingen (fair-PK median-of-3, sequenced, zelfde machine)
Let op: INSERT/READ (onveranderde paden) varieerden tussen de twee median-runs met ±10-20% —
er blijft omgevingsruis op deze machine; de SQLite-ratio binnen elke run is daardoor de meest
betrouwbare maat. Richting is consistent positief op alle DELETE/UPDATE-ratio's.
Validatie
probe-verificatie af.