glm-5.3-flash
758ccfb359
Six tasks against the wave-2 contract surface as reviewed (no amendments from the gate): - engine-sqlite: the default kv engine — WAL + synchronous=NORMAL, prepared statements, the indexed size column probe (B5's row shape), has-as-EXISTS, virgin-store no-tables-yet tolerance, spawn_blocking discipline - engine-sqlite-window: the engine-state seam's window family only (ADR-012 §5's reduction — gc_window, stage/take; no pin rows, no sweep-lock body) - store-sqlite-construction: KvEngine::Sqlite slots in, the dual-tier/kv-only constructors with the constructor-tunable window delay (default 5 min), ensure_gc_schema at construction, the one-window-host posture - store-sweep-durable-window: the sweep's SQL-backed form — overdue rows execute with re-arbitration before/alongside marking, candidates stage at mark_end + window, counts exact relative to the schedule (ADR-012 §6.7); the inline form preserved verbatim - suite-column-sqlite: the first SQL-backed column, server-less — form-independent reference rows mirror directly; the sweep rows are schedule-relative (the recorded INV-4/5 mirror amendment) - review-wave-3: the engine-wave gate (engine-vs-contract conformance) Verification: dependency graph validated (all ids resolve, no cycles, topological order clean); docs-only change. Refs: docs/plans/implementation.md §Wave 3
88 lines
4.0 KiB
Markdown
88 lines
4.0 KiB
Markdown
---
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id: engine-sqlite-window
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name: sqlite engine-state window family — the durable single-node delete window
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status: pending
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depends_on: [engine-sqlite]
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scope: narrow
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risk: low
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impact: component
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level: implementation
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tags: [wave-3, engines, sqlite, gc]
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---
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## Description
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Implement the engine-state companion seam's **window family** on the
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sqlite backend (`src/sqlite.rs` or its seam module): the
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`EngineWindowState` impl per ADR-010 §2 **as reduced by ADR-012 §5** —
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the window family only. The pin clauses and the sweep-lock body are
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**dropped dead machinery** for sqlite (ADR-012 §5's table: pin clauses
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**no**, sweep-lock clause **no** — the single-flighter is the
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in-process lock; a sqlite fleet is a recorded non-option, ADR-010 §3).
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Nothing of `EngineFleetState` may exist on this engine.
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- **`ensure_gc_schema`** — creates **`gc_window` only**
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(`gc_window (key BLOB PRIMARY KEY, visible_after INTEGER)`; the
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timestamp encoding — `SystemTime` ↔ integer, sub-second precision
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for the test tunings — is a recorded design point). Never `gc_pins`;
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the embedder's liveness table is never created here (ADR-008's
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schema-ownership rule — the sweep reads it and never owns it).
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Called at store construction by the store core
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(`store-sqlite-construction` wires the call); the clause body is
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engine-side.
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- **`window_stage`** — stage candidates into the durable window,
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**idempotent per `(key, deadline)`** (`INSERT OR IGNORE` semantics —
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the body's discipline; the store stages each candidate once per
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sweep, and a re-stage of the same key at a new deadline updates the
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row). Virgin store: tolerated (the table exists from construction;
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a no-tables-yet database stages lazily or errors nothing — the
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Backend trait's engine posture carries here).
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- **`window_take(now)`** — take overdue candidates
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(`visible_after <= now`): the rows **leave the window table and
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return as keys** for the calling sweep to re-arbitrate and delete —
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the executor is the next sweep (ADR-012 §6.7). Empty when nothing is
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overdue; virgin store: empty. The take is one atomic step (selected
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rows removed and returned together — a row is never handed out
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twice).
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- **Contract tests** per the applicability row (ADR-012 §5's table is
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the contract-test matrix): the schema creates the window table only
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(assert `gc_pins` does not exist); stage idempotence per
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`(key, deadline)` incl. the re-stage-at-new-deadline form; take
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returns exactly the overdue set, removes it, leaves future rows;
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empty/virgin shapes; the timestamp encoding's boundary
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(`visible_after == now` is overdue — `<=` per the seam doc).
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The store core drives these clauses (`store-sweep-durable-window`);
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this task ships the clauses and their engine-level contract tests.
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## Acceptance Criteria
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- [ ] The sqlite backend implements `EngineWindowState` — the window
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family only; no pin-clause or sweep-lock body exists anywhere in
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the sqlite engine
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- [ ] `ensure_gc_schema` creates `gc_window` only; `gc_pins` is never
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created by sqlite (contract-tested)
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- [ ] `window_stage` is idempotent per `(key, deadline)`; a re-stage
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at a new deadline updates the row
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- [ ] `window_take` returns exactly the overdue set (`<= now`
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boundary), removes it atomically, leaves future rows; empty on
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none/virgin
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- [ ] Clause contract tests green; `cargo test` (default) green;
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`cargo clippy --all-targets -- -D warnings` and
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`cargo fmt --check` green
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## References
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- src/gc.rs (`EngineWindowState` — the seam contract and its clause docs)
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- docs/architecture/decisions/010-backend-io-seams-and-fleet-state.md §2
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- docs/architecture/decisions/012-pre-decomposition-consistency-rulings.md §5 (the applicability table; the sqlite reduction), §6.7 (the executor)
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- docs/architecture/decisions/008-trait-size-probe-fleet-gc-and-large-engines.md §2 (the durable window's semantics)
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- docs/architecture/decisions/005-pooled-cas-and-gc-mechanism.md (the delete-window protocol)
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## Notes
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> To be filled by implementation agent
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## Summary
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> To be filled on completion |