shoney.arickathil
80046556af
- 00: story framing - 01: principles doc - 02: VM core - 04: single binary e2e - 05: language surface - 08: shard-actor runtime - 09: database engine - 10: HTTP service
63 lines
2.8 KiB
Markdown
63 lines
2.8 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, every `ref`/`multi` field a relation — the `@`-annotations
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(`@table`, `@unique`) are the built-in ORM, mapped at compile time with no
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external layer. `insert` and `select` stop trapping (`DB_STUB` retires)
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and run 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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- Annotations, not macros: `@table`/`@unique` are compiler-known and
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resolved at compile time; user-defined macros stay rejected (systems-track
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verdict table). A `ref T` field compiles to a typed row id (FK); `multi T`
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to the owning-side collection edge — the relation model the examples
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(pricing's `Product`/`Price`) already write.
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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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## 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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