shoney.arickathil
1749440351
- 9b spec gains section 6 "Ownership, borrows, and GC across the engine boundary": two one-way copy gates (no VM pointer enters a row, everything a select returns is copied out), so the collector never traces engine memory and the engine never touches refcounts - row views are borrows WITHOUT a runtime net: rows share the VM's field encoding but not its header, so no borrow word backs them -- the compile-time escape rule is load-bearing alone - cursor stability settled: scans materialize their id list before the body, row updates through the view stay legal (raise mode updates an indexed column mid-scan and is the proving fixture), insert/delete on a table with an open cursor is a new WO-E5xx - GC-pause interaction recorded: collector runs between statements, a long scan delays slices -- accepted, documented - iteration-7b ordering constraint: GC inference must classify before table-field validation, diagnostic names the inference reason -- noted in 7b story, iteration-9 plan constraints, 9b plan tasks - stories 09/09b Info sections point at the analysis; 9b plan Tasks 3/5 carry the enforceable checkboxes (ASan boundary assertion) Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
64 lines
2.9 KiB
Markdown
64 lines
2.9 KiB
Markdown
# Iteration 9 — database engine
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> Format: `product/story-iteration-template`. Part of
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> [Story — one language, one runtime, one database, one binary](00-story.md).
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## Goals
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- The language's oldest promise executes on the new runtime: every class is
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a table. `insert` and `select` stop trapping (`DB_STUB` retires) and run
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against class-shaped row storage inside the VM's shards.
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- Data survives anything: a typed write-ahead log with ack-after-fsync,
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parallel boot replay, and a crash battery proving no committed row is
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ever lost and no half-applied transaction ever visible.
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## Acceptance Criteria
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- What to achieve?
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- **Given** a class annotated `@table` and a method inserting rows,
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- **when** the method runs,
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- **then** the insert is WAL-logged before acknowledgment, visible to
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subsequent `select`, and the pricing fixture that previously trapped
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`DB_STUB` now passes with real data.
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- What to achieve?
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- **Given** kill -9 at arbitrary points during committed writes,
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- **when** the process reboots and replays,
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- **then** every acknowledged commit is present, no unacknowledged
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partial write is visible, and replay across shards completes without
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manual steps.
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- What to achieve?
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- **Given** a `@unique` field and a duplicate insert,
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- **when** it executes,
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- **then** the insert traps with the unique-violation code and
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secondary indexes remain consistent (maintained only through the
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engine's row choke points).
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## Out Of Scope
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- Cypher/document query paradigms and `LIVE` subscriptions (the query
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layer's later phases; `prototypes/wo-db` stays the reference).
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- Cross-shard 2PC transactions; Postgres mirroring (exists on the Rust
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side; ports after parity).
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## Info
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- Doctrine: RAM is authoritative; the WAL makes it durable; indexes drift
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unless writes go through the row API — the Rust runtime learned this
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lesson, the C engine enforces it.
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- The wo-db overlap manifest keeps the C++ prototype and this engine
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answer-compatible where features overlap.
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- **Ownership/GC analysis (2026-08-15):** the engine and the VM heap are two
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memory worlds crossed only by copy — rows store no VM pointers, GC-managed
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values in stored fields are a compile error, and everything a query returns
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is copied out — so the collector never traces rows and the engine never
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counts references. The full analysis (row views as borrows without a
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runtime net, cursor stability, GC-pause interaction) lives in the 9b
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design's section 6:
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[`2026-08-15-table-relations-query-design.md`](../../superpowers/specs/2026-08-15-table-relations-query-design.md).
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## Proposed Solution
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- Execute the existing plan: `docs/superpowers/plans/2026-08-01-db-engine-binding.md`
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(class-shaped row slabs with a choke-point row API, typed WAL + parallel
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replay + crash battery, insert execution, doctrine-enforced indexes +
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`@unique` trap, select subset, db corpus).
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