omnigraph/docs/releases/v0.8.0.md

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# Omnigraph v0.8.0
feat(engine): graph lineage in __manifest — single-source fold, v3→v4 migration, schema-version floor (#299) * docs(rfc-013): bank the #295 spec-review comments as step-5 constraints (§5.1) 3b shipped a minimal WriteTxn{branch,base} and deferred the full §4.1 opener unification (pinned-base opener, shared Session, write-local handle cache, strict-op conflict-timing move) to step 5. The greptile comments on the #295 spec were moot for #298 (none of those constructs were built) but are load-bearing for step 5: (1) the handle cache must be Send+Sync (Mutex, not RefCell); (2) the strict-op timing move needs an explicit retry contract — txn discarded after any commit, retry re-opens a fresh base — which is the SAME contract as the stale-view false-fail (§1d.2); (3) the opener-equivalence test must advance HEAD externally then assert pinned-base, not the trivial HEAD==base. * feat(engine): fold graph lineage into the __manifest publish CAS (RFC-013 Phase 7) Graph lineage no longer lives in a second write to _graph_commits.lance. Each commit's graph_commit + graph_head:<branch> rows now ride the SAME __manifest merge-insert as the table-version rows (one atomic version), and CommitGraph reads its cache from the manifest projection (read_graph_lineage). _graph_commits.lance is no longer written commit rows (it remains only as a Lance branch-ref carrier). Mechanism: a LineageIntent { graph_commit_id (ULID, minted once), branch, actor, merged_parent, created_at } threads through ManifestBatchPublisher::publish. Inside the publisher retry loop the parent is resolved per attempt from the just-loaded branch-scoped manifest (the should_replace_head winner over the visible graph_commit rows — branch-correct by Lance branch isolation; the graph_head row is written for forward-compat + the §7.1 contention point but is not the parent source, so a freshly-forked branch resolves the right fork-point parent). A CAS-conflict retry re-reads the advanced head → correct new parent; the commit_id is stable across retries. Closes two known gaps BY CONSTRUCTION (one write, no second step to fail/ race): - manifest→commit-graph atomicity (no crash window between manifest + lineage), - commit-graph parent under concurrency (no refresh→append TOCTOU; the per-write commit_graph.refresh() is gone). Recovery, branch-merge, and genesis route their lineage through the same CAS (merge: one commit_merge_with_actor; recovery: publish_recovery_commit folds the recovery commit, actor=omnigraph:recovery; genesis rides the init __manifest write). The dead _graph_commits write helpers (append_commit/_merge/_actor) are #[allow(dead_code)] (the actor sidecar table is still enumerated by optimize). Verified (sequential): build clean; the new lineage_projection gate (manifest-only — _graph_commits/_actors have 0 rows; full lineage reconstructs via the projection); branching/merge_truth_table (exhaustive, branch-aware)/composite_flow/point_in_time/ changes/consistency/recovery; failpoints (59, incl. recovery lifecycle + the now-closed atomicity gap); full --workspace. Cost tests REVERT to their pre-fold values (writes +1, write_cost ceiling 80) — the proof of true single-CAS (no extra write). invariants.md marks both gaps CLOSED. PENDING (next stages, this PR): the §7.1 concurrent graph_head one-winner gate (stage 5 — two concurrent same-branch commits, exactly one wins); the stamp bump v4 + migrate_v3_to_v4 backfill + read-only refuse for EXISTING graphs (stage 4); full doc-sync of storage.md/architecture.md/writes.md. * feat(engine): migrate existing v3 graphs to manifest lineage (RFC-013 Phase 7 stage 4) The Phase-7 fold made CommitGraph read lineage from the __manifest projection, so a pre-Phase-7 (internal-schema v3) graph — lineage in _graph_commits.lance, none in __manifest — would read an empty commit DAG. Stage 4 makes existing graphs upgrade seamlessly and not break reads. - Stamp 3 -> 4 + migrate_v3_to_v4: bumps INTERNAL_MANIFEST_SCHEMA_VERSION and adds the 3 => migrate_v3_to_v4 arm. The migration reads this branch's _graph_commits/_actors, emits one graph_commit row per commit + exactly one graph_head:<branch> for the head (should_replace_head winner, deterministic id-sort — no hash-map-order in migration output), merge-inserts into __manifest, then set_stamp(4) LAST. Idempotency guard first (read_graph_lineage non-empty -> just stamp); crash before set_stamp re-enters at v3 and the guard completes it. Does NOT touch the unenforced-PK metadata. Runs per branch: migrate_on_open backfills main; load_publish_state backfills each branch on its first write (root_uri/branch threaded through migrate_internal_schema). - v3-read fallback: CommitGraph version-gates the lineage source — stamp < 4 reads the (re-activated) _graph_commits.lance; >= 4 uses the manifest projection. So a READ-ONLY open of an un-migrated graph reads correct history with no write. Correctness catch: the legacy _graph_commit_actors.lance was never branched, so the fallback reads it FLAT (no branch checkout) while checking out the branch only on the commits dataset. - Read-only stamp-refuse: a ReadOnly open of a FUTURE-stamped graph now refuses with the same upgrade error (future-proofing the next format bump; the write path already refused via migrate_internal_schema). - Docs: storage/architecture/writes/invariants/constants updated to manifest-stored lineage; release note docs/releases/v0.8.0.md (format v4, old writers clean-break, data preserved, upgrade writers first). 6 new tests (v3 backfill, idempotent, v3 read-only fallback, future-stamp refuse in both modes, crash-before-stamp completes, legacy branch+flat-actor read). Full engine suite + failpoints (59) + cargo test --workspace --locked green; check-agents-md passes. * test(engine): graph_head concurrency gate — disjoint same-branch writers form a linear commit DAG (RFC-013 Phase 7) Two (or N) writers committing disjoint tables on one branch still share the mutable `graph_head:<branch>` manifest row, so the only row-level CAS contention is that row. The contract — exactly one writer wins each CAS round; the loser retries inside the publisher, re-resolves its parent off the freshly-advanced head, and re-commits, so every writer lands and the graph_commit DAG stays a single LINEAR chain (no fork) — had no acceptance test. This adds it. - concurrent_disjoint_writes_share_head_and_form_linear_chain: two disjoint writers + distinct LineageIntent, tokio::join!; both commit; the on-disk DAG is genesis -> c -> c' (asserted linear: exactly one genesis, no two commits share a parent, the head is the unique non-parent). - n_concurrent_disjoint_writers_converge_to_one_linear_chain: N=8 disjoint writers each with an app-level retry loop (the publisher's internal budget can be exhausted under contention); all converge to one linear chain of 8. - concurrent_disjoint_writes_form_linear_chain_on_s3: the same race on a real object store (true conditional-put CAS), bucket-gated. Cites both tests from the §7.1 contention note in invariants.md. Test-only; no production change. * perf(engine): fold the lineage parent scan into the publish path's single __manifest scan (RFC-013 P2) Each lineage publish scanned `__manifest` twice: `load_publish_state` read table state via one scan, then `resolve_lineage_rows` did a second full `read_graph_lineage` scan only to find the parent commit. Fold the `graph_commit` extraction into the existing scan. - `read_manifest_scan` gains a `collect_lineage` flag. The publish path (`read_publish_scan`) collects the `graph_commit` rows in the same pass; the table-state hot path leaves them in the forward-compat skip arm, so it never pays the O(commits) lineage JSON decode (it also skips reading the `object_id` column entirely). One shared `decode_graph_commit_row` serves both the folded path and the standalone `read_graph_lineage`, so the two cannot drift. - `resolve_lineage_rows` is now sync and takes the already-parsed rows; the per-attempt re-read is preserved because `load_publish_state` runs once per CAS attempt, so a retry still re-parents off the advanced head. - `load_publish_state` returns a named `LoadedPublishState` instead of a four-tuple; the thin `read_registered_table_locations` / `read_tombstone_versions` accessors fold away. `read_manifest_entries` becomes `#[cfg(test)]`: the fold removes its last production caller, leaving only the test-only namespace module (`db/manifest.rs`: `#[cfg(test)] mod namespace`), so gating it keeps it from becoming dead code in non-test builds. Measured at depth ~5: per-write `__manifest` reads drop 44 -> 26 (total reads 54 -> 36). write_cost.rs gains a `manifest_reads <= 34` sub-ceiling that trips if a publish-path scan is re-added, and its calibration comment is corrected. * test(engine): red — transient legacy-open failure silently completes the v3→v4 migration A pre-Phase-7 (internal schema v3) graph keeps its graph lineage in `_graph_commits.lance`; the v3→v4 internal-schema migration backfills it into `__manifest` and stamps v4. `read_legacy_commit_cache` currently maps EVERY `Dataset::open` error to "no legacy data" (`Err(_) => empty`), so a transient or corrupt open during the one-time migration backfills nothing and still stamps v4 — orphaning the real lineage permanently (the migration runs once; the v3 fallback is then disabled). Add a `migration.v3_to_v4.legacy_open` failpoint that injects a non-not-found Lance error at the legacy open, and a fault-injection regression test in the `failpoints` binary. Against the current swallow the migration completes anyway, so the test fails on its "migration must abort" assertion — the predicted symptom. The fix follows in the next commit. Test support reachable from the `failpoints` integration binary (it compiles the crate without `cfg(test)`): the v3-fixture helpers and a stamp/row-count reader are gated `cfg(any(test, feature = "failpoints"))`, still excluded from release builds. Failpoint tests stay in the integration binary because the fail registry is process-global. * fix(engine): propagate non-not-found legacy-open errors in the v3→v4 migration `read_legacy_commit_cache` mapped EVERY `Dataset::open` error to an empty cache (`Err(_) => empty`) on both the legacy commits dataset and its actor sidecar. The v3→v4 internal-schema migration reads this once before stamping internal-schema v4; a transient or corrupt open therefore backfilled nothing and stamped v4 anyway, orphaning the graph's real lineage permanently (the migration runs once, and the stamp-gated v3 fallback is disabled at v4). This is the "no silent failures" deny-list violation, and realistic on object storage. Both opens now match the not-found variants — Lance maps an object-store NotFound to `DatasetNotFound` — as the benign "no legacy data" / "no authors" signal, and propagate anything else as a loud error. The two arms share the variant contract but carry different rationale (commits-absent is the legitimate empty signal; actor-sidecar-absent is benign, but a corrupt actor open silently wiping authorship before stamping v4 is the same loss hole), commented at each site. Pinned by the `lance_surface_guards.rs::dataset_open_missing_returns_not_found_variant` guard (turns red if a Lance bump changes the absence variant) and greens the fault-injection regression test from the previous commit. * test(engine): cover the per-branch v3→v4 migration against a real Lance branch `seed_legacy_v3_lineage` writes every commit (including the "feature"-tagged one) to MAIN's `_graph_commits.lance` with `manifest_branch` as a mere field, so the production per-branch migration path — `read_legacy_commit_cache` checking out a real Lance branch, and a branch-scoped `__manifest` — was never exercised. Add `seed_legacy_v3_lineage_with_branch`, which forks a real `feature` Lance branch on BOTH `_graph_commits.lance` and `__manifest` (the branch inherits main's stripped v3 state), and a test that migrates the BRANCH and asserts the branch's lineage lands in the BRANCH's `__manifest` (genesis + A + branch commit, `graph_head:feature` → branch commit, parents + actors intact) with main's `__manifest` untouched. This empirically resolves the open question behind the merge robustness work: the fast-path `read_graph_lineage(dataset)` has no `manifest_branch` filter, but `__manifest` is Lance-branched per graph-branch, so a branch reads only its own lineage — the test confirms migrating one branch does not leak into another. No branch filter is needed. * refactor(engine): type the lineage-backfill merge conflict via the publisher classifier `state::merge_lineage_rows` (the v3→v4 lineage backfill's standalone `__manifest` merge-insert) stringified its `execute_reader` error, discarding the Lance variant. Route it through the publisher's `map_lance_publish_error` (now `pub(crate)`) so a concurrent first-open's row-level CAS loss surfaces as the SAME typed `OmniError::Manifest{ details: RowLevelCasContention }` the publisher's own retry consumes — one vocabulary, no raw-Lance matching in the migration. Deliberately NOT unified with `optimize::is_retryable_lance_conflict`: that classifier also matches `CommitConflict`/`RetryableCommitConflict` from the compaction commit path, which a row-level merge-insert never emits. Cross-linked with a comment at both sites. Behavior-preserving: the only path that changes is the error TYPE on a CAS loss (previously an opaque `Lance` string, now a typed conflict); no success/failure outcome changes. The bounded re-open retry that consumes the new type lands next. * test(engine): red — concurrent v3→v4 migrations error instead of converging `migrate_v2_to_v3` is concurrent-runner idempotent by design; v3→v4 regressed it. `merge_lineage_rows` uses `conflict_retries(0)` and `migrate_v3_to_v4` has no app-level retry, so when two processes open the same legacy graph at once the backfill's row-level CAS loser errors the whole open instead of converging. The test opens two `__manifest` handles at the same pre-migration (v3, empty-lineage) HEAD and runs both `migrate_internal_schema` calls under `tokio::join!`, forcing the `graph_head:main` CAS to fire every run. Against the current code the loser fails with `RowLevelCasContention` ("Attempted 0 retries.") — the predicted symptom — so the "both must converge" assertion panics. The bounded re-open retry that makes both converge lands next. * fix(engine): make the v3→v4 lineage backfill converge under concurrent runners `migrate_v2_to_v3` is concurrent-runner idempotent; v3→v4 was not. Two processes (or open-for-write handles) opening the same legacy graph at once both reach the backfill merge, and `merge_lineage_rows`'s `conflict_retries(0)` made the row-level CAS loser error the whole open instead of converging. Two contention points, both now handled all-or-nothing: 1. The backfill merge on `graph_head:<branch>`. Wrap (fast-path re-read → read legacy → merge) in a bounded re-open retry loop: a `RowLevelCasContention` loss re-opens the manifest past the winner's (atomic) commit and re-loops; the fast-path re-read then sees the winner's lineage and stamps. On budget exhaustion it returns a `RowLevelCasContention`-typed error so the publisher's OUTER retry loop completes it. The retry decision reuses the publisher's `is_retryable_publish_conflict` so the two stay in lockstep. 2. The terminal stamp bump. Making the merge loser converge newly lets BOTH runners reach `set_stamp(4)` — an `UpdateConfig` commit on the same key — so the loser gets `lance::Error::IncompatibleTransaction` (NOT a row-level CAS, so the merge loop doesn't catch it). This surfaced only under the concurrent full-suite run, not the isolated test. Both write the SAME value, so the conflict is benign: `commit_v4_stamp_idempotently` re-opens and, if the stamp already reached the target, succeeds; else re-applies (bounded). Greens the race test from the previous commit (3x isolated, 5x full-suite, no flake). The new `IncompatibleTransaction` match is pinned by `lance_surface_guards.rs::lance_error_incompatible_transaction_variant_exists`. * fix(engine): refuse a future internal-schema stamp on the branch read path `load_commit_cache_for_branch` dispatched on the branch's internal-schema stamp — `< CURRENT` to the v3 legacy fallback, `>= CURRENT` to the manifest projection — but never refused a `> CURRENT` branch stamp, so a newer-binary shape would be misread by the projection rather than rejected. Add `refuse_if_stamp_too_new(stamp)` (re-exported `pub(crate)` from `migrations`) right after the branch stamp is read, mirroring the main read path's `refuse_if_internal_schema_too_new`. This is defense-in-depth, not a live hole: migrations run main-first (main migrates on open; each branch on its first write), so main's stamp is always >= every branch's and the main path refuses first. The guard closes the gap if that ordering invariant is ever weakened. Tested by force-stamping a real branch past CURRENT and asserting the branch read refuses with the upgrade error (the test misreads via the projection — returns Ok — without the guard, confirmed by removing it). * docs(rfc-013): record the v3→v4 migration robustness fixes invariants.md Known Gaps: the `migrate_v3_to_v4` entry now states the migration is loud on non-not-found legacy-open errors and concurrent-runner idempotent (bounded re-open retry on the merge CAS + idempotent stamp bump), and that the branch read path refuses a `> CURRENT` stamp. lance.md: note the two new surface guards the migration depends on (`dataset_open_missing_returns_not_found_variant`, `lance_error_incompatible_transaction_variant_exists`). testing.md: note the migration fault-injection test in the failpoints row. * refactor: remove dead code and silence warnings across engine + cluster Dead-code sweep follow-up to the RFC-013 stack. No behavior change. - engine: delete the orphaned `validate_edge_cardinality` — the load path uses `validate_edge_cardinality_with_pending_loader` for every mode (including Overwrite, which it treats as the replacement table image), so the old standalone validator had no caller — and correct its sibling's now-stale doc reference. Gate `TableStore::append_batch` `#[cfg(test)]`: it is the inline- commit residual kept only for recovery test setup, with no non-test caller. - cluster: drop unused imports in `lib.rs`, delete the unused `ClusterStore::payload_display`, and raise `LiveGraphObservation` / `GraphObservationJson` / `PolicyTarget` to `pub(crate)` to match the functions that return them. Both lib crates now build warning-free. * fix(engine): match Lance's typed DatasetAlreadyExists, not the message string The internal create-or-open idempotency fallbacks in `db/commit_graph.rs` and `db/recovery_audit.rs` classified the "already exists" race by `err.to_string().contains("Dataset already exists")` — a Lance display string, not an API contract. A wording change upstream would silently break the fallback (a re-create would error instead of opening the existing table). Match the typed `lance::Error::DatasetAlreadyExists { .. }` variant instead — the same discipline as the v3→v4 migration's not-found classifier — pinned by the new `lance_surface_guards.rs::lance_error_dataset_already_exists_variant_exists` guard so a Lance rename turns red instead of silently regressing. * refactor(engine): consolidate now_micros into one crate::db helper Four `fn now_micros() -> Result<i64>` copies (commit_graph, recovery_audit, graph_coordinator, manifest/graph) had already drifted: three mapped the clock error to `OmniError::manifest("...UNIX_EPOCH...")` while recovery_audit used `OmniError::manifest_internal("...unix epoch...")`. Replace all four with one `pub(crate) fn now_micros()` in `db/mod.rs` (the majority `manifest` variant), and repoint the eight call sites at `crate::db::now_micros()`. No test asserts on the failure message, so unifying the variant is behavior-safe; the timestamp-mapping contract can no longer fork across the rows it stamps. * refactor(engine): drop the dead snapshot param from roll_back_sidecar `roll_back_sidecar` took `snapshot: &Snapshot` only to discard it with `let _ = snapshot;` — rollbacks now always publish (the restored HEAD plus a recovery-commit lineage row), so the snapshot is never read to decide whether to skip a publish. Remove the parameter, the two call-site arguments, and the suppressor. A signature must not advertise inputs it does not consume. The `Snapshot` import stays — `process_sidecar`, `roll_forward_all`, and `record_audit_recovery_rollforward` still take it. * test(engine): red — open_at_branch wedges a branch on a missing commit-graph ref A v4 graph keeps its graph lineage in `__manifest` (RFC-013 Phase 7); the `_graph_commits.lance` branch ref is a derived artifact. An interrupted fork-reclaim or a `cleanup` race can drop that derived ref while the manifest lineage stays intact. Per invariants 7 + 15 a missing derived ref must not fail a logical read of the lineage. This wedge builds a real v4 `feature` branch (its `graph_head:feature` row in `__manifest`), force-deletes ONLY the `_graph_commits.lance` `feature` ref, then asserts the branch reads (`open_at_branch` / list-commits / `merge_base`) succeed from `__manifest` while a write that needs the derived ref (`create_branch`) fails loudly with the typed actionable error. Red against current code: `open_at_branch`'s hard `checkout_branch(branch)?` on the missing ref errors `OmniError::Lance` (Lance "Not found: _graph_commits.lance/tree/feature/_versions"), wedging the logical read. * fix(engine): read manifest lineage independent of the derived _graph_commits ref `CommitGraph::open_at_branch` did a hard `checkout_branch(branch)?` on the `_graph_commits.lance` branch ref before reading lineage — so a missing derived ref (an interrupted fork-reclaim, or a `cleanup` race) wedged the branch's commit-list / merge-base / snapshot resolution even though the lineage is readable from the authoritative `__manifest` (RFC-013 Phase 7). That is a derived/physical artifact failing a logical read — invariants 7 and 15. Make the held commits handle `Option<Dataset>` (mirroring `actor_dataset`). `open_at_branch` and `refresh` check out the derived ref best-effort: a typed not-found (`RefNotFound`/`NotFound`) yields a `None` handle while the read re-syncs from `__manifest`; any other open error still propagates. The manifest existence gate is unchanged — `load_commit_cache_for_branch` keeps its hard `?`, so a truly absent branch still fails loudly at the manifest. `create_branch` (the only writer that forks a ref) and the folded-in version lookup return a loud, actionable error on `None`, deferring repair to `cleanup`'s existing orphan reconciler rather than inlining a write on a read-side refresh. Reads (`head_commit`/`load_commits`/`get_commit`/`merge_base`) never touch the handle. Greens the wedge regression from the preceding commit. * fix(engine): v3→v4 retry loops return retryable contention on exhaustion `commit_v4_stamp_idempotently`'s retry loop used `0..=STAMP_RETRY_BUDGET` (6 iterations) with an `attempt < STAMP_RETRY_BUDGET` guard, so the LAST iteration's `IncompatibleTransaction` fell through to `Err(e) => OmniError::Lance(...)` — stringified, non-retryable — instead of the intended `RowLevelCasContention`, and the post-loop contention return was dead code. The publisher's outer retry only re-runs `is_retryable_publish_conflict`, so under sustained concurrent v3→v4 migration the one-time stamp bump could fail instead of converging, defeating the idempotency the migration is supposed to add. Fix the loop to `0..BUDGET` with an UNGUARDED `IncompatibleTransaction` arm: the retryable variant is always handled inside the loop (re-open + same-value check + retry), so it can never reach the stringifying catch-all, and the post-loop is the SINGLE reachable exhaustion path — the typed `RowLevelCasContention`. The `Err(e)` arm now catches only genuine non-contention errors. Apply the same range alignment to the sibling merge loop in `migrate_v3_to_v4` (behaviorally correct today — its `Err(err)` returns the already-typed contention — but it carried the identical off-by-one structure the stamp loop was copied from; aligning both stops the next copy from re-introducing it). Test-first. The exhaustion path is otherwise near-unreachable — a real concurrent winner stamps the same value, so the re-read returns Ok on the first retry — so a new `migration.v4_stamp.force_incompatible` failpoint forces every stamp attempt to lose, driving exhaustion deterministically. Against the pre-fix loop the new `v4_stamp_exhaustion_returns_retryable_contention` test goes red with `Lance("Incompatible transaction: injected failpoint triggered…")`; with the fix it asserts the typed `RowLevelCasContention`. Found by automated review on #299. * feat(engine): minimum-supported internal-schema floor + retirement tripwire The internal-schema migration chain (`migrate_internal_schema`) had a too-new ceiling but no floor, so every old `migrate_vN_…` arm and the v3 legacy readers it needs stay forever — the pile grows by one migration + readers + tests every schema version. Add `MIN_SUPPORTED_INTERNAL_SCHEMA_VERSION` (1 today, a pure no-op: `read_stamp` floors an absent stamp at 1 and no real graph carries 0) as the oldest stamp this binary opens; raising it is how the chain sheds old code. Collapse the one-sided `refuse_if_stamp_too_new` into `refuse_if_stamp_unsupported` checking both bounds, so the floor lands at all three stamp-enforcement sites — the write-path migrate dispatcher, the read-only open guard, and the branch lineage-read path (`commit_graph.rs`) — via one compiler-enforced rename. A hand-wired floor twin would have had to touch each site, and the branch-read path is easy to miss; one combined guard cannot half-enforce. Rename the read-only wrapper `refuse_if_internal_schema_unsupported` to match. A compile-time tripwire (`const _: () = assert!(LOWEST_REGISTERED_MIGRATION_SOURCE == MIN_SUPPORTED…)`) fails the build if a future floor bump forgets to delete the now-dead migration arm (or vice versa) — stronger than a runtime test, impossible to skip, and it doubles as the use that keeps the mirror const live. Tests: a sub-floor graph is refused in both open modes (twin of `future_stamp_is_refused_in_both_open_modes`); the guard accepts exactly [MIN, CURRENT]. No behavior change for any real graph. The retirement runbook lives on the `MIN_SUPPORTED` doc-comment + invariants.md. * fix(engine): compose migration contention with publisher retry; precise recovery-converge audit commit Three review-surfaced fixes on the RFC-013 Phase 7 path. Publisher retry vs migration contention: `publish()` propagated a `load_publish_state` error fatally via `?`, so a `RowLevelCasContention` surfaced by the v3->v4 migration's exhausted merge/stamp budgets aborted the publish instead of being retried — only `merge_rows` conflicts hit the retry. This contradicted the migration's own design, which returns that typed error EXPECTING the publisher to re-run the load (by which point a concurrent winner has usually finished the migration, so the next scan is a no-op). Route a retryable load error through the same retry path as a retryable `merge_rows` conflict. Regression test (failpoints): a one-shot retryable contention injected into `load_publish_state` now commits via the retry; red without the fix (the write fails with the injected contention). Recovery-converge audit commit id: `converge_or_defer_roll_forward` recorded the branch HEAD as the audit row's `graph_commit_id`, but a concurrent user write can advance `graph_head` past the recovery commit between the winner's publish and this read — attributing the audit to a later, wrong commit. Use the latest `RECOVERY_ACTOR`-authored commit (what `publish_recovery_commit` mints), which is the recovery commit by construction. The audit's actor was already correct (it comes from `sidecar.actor_id`, not the commit). Dead param: drop the unused `snapshot` from `record_audit_recovery_rollforward` (removing the `let _ = snapshot;` suppressor). `storage` stays — it is used to delete the sidecar.
2026-06-25 13:55:34 +02:00
feat(engine): retire commit-graph tables (#311) * docs(dev): write-latency roadmap (validated cost model + layered fix) Records the validated 6-LIST warm-write cost model, the two root causes (un-GC'd _versions/; re-resolving latest by listing), and the layered fix (GC + capture-once reuse), plus how commit-graph-table retirement feeds in. Linked from docs/dev/index.md next to the RFC-013 docs. * feat(engine)!: strand storage versioning — one internal-schema version, no in-place migration Set MIN_SUPPORTED == CURRENT == 4: this binary reads exactly one `__manifest` internal-schema version and refuses any older graph on open with a rebuild-via-export/import message, instead of migrating it in place. Storage format changes become a deliberate cutover, not a permanently-carried in-place migration — the pre-release "complexity must be earned" contract. Delete the entire in-place migration apparatus and everything that existed only to support it: the `migrate_vN` arms + dispatcher + stamp-bump helpers + the schema-version-floor tripwire; `migrate_on_open` (both open modes now refuse); the legacy `_graph_commits.lance` readers + the v3 test fixtures + migration tests + `migration.v3_to_v4.*` failpoints + the two surface guards that pinned Lance variants only the migration matched on; and `state::merge_lineage_rows`. Keep `read_stamp` / `stamp_current_version` / `set_stamp` / `refuse_if_stamp_unsupported` — the seam a future one-shot converter plugs into. `load_commit_cache_for_branch` now reads the `__manifest` projection unconditionally (sub-v4 graphs are refused at open). Adds `sub_current_graph_is_refused_on_open_with_rebuild_hint`. The commit-graph TABLES are still created/used as branch-ref ledgers — their retirement (CommitGraph -> pure `__manifest` projection) is the next commit. BREAKING CHANGE: a graph created by omnigraph <= 0.7.2 (internal schema v3) is refused on open. Rebuild it: `omnigraph export` with the old release, then `omnigraph init` + `omnigraph load` with this one. Data, vectors, and blobs are preserved; commit history and branches are not. * feat(engine)!: retire `_graph_commits.lance` / `_graph_commit_actors.lance` — CommitGraph is a pure `__manifest` projection Since RFC-013 Phase 7, graph lineage lives in `__manifest` (`graph_commit` / `graph_head` rows) and branch authority is `__manifest` (branch create forks it first). The two commit-graph datasets were vestigial: `_graph_commit_actors.lance` was never written or read; `_graph_commits.lance` carried zero commit rows and only mirrored the manifest's branch refs (a deny-list "parallel copy"). Retire both. - `CommitGraph` collapses to a pure projection: drops its Lance dataset handles (`dataset`/`actor_dataset`) and all branch methods; `open`/`open_at_branch`/ `refresh`/`init` open NO dataset, building the cache from `ManifestCoordinator::read_graph_lineage_at`. Removes ~1.4s of cold-open dataset opens. - `graph_coordinator`: `commit_graph` is now non-`Option` (always a valid projection). `branch_create`/`branch_delete` go through `ManifestCoordinator` only — a single atomic op, replacing the two-step manifest-fork + commit-graph-fork + rollback. Deleted `create_commit_graph_branch`, `reclaim_commit_graph_branch`, `ensure_commit_graph_initialized`, and every `storage.exists(_graph_commits.lance)` gate. - `optimize`: dropped `reconcile_commit_graph_orphans` and the two tables from the internal-table compaction set (now `__manifest` only). - `instrumentation`: `INTERNAL_TABLE_DIRS` no longer lists the two tables. - Fresh graphs create neither table; `lineage_projection.rs` now asserts both `.lance` dirs are absent. Deleted the obsolete commit-graph-branch-race failpoint tests + their failpoint names, and updated the `maintenance` optimize tests (one internal table, not three). Review-pass fixes folded in: - Removed two stale `omnigraph.rs` in-source tests the prior run missed (a disk-full link failure masked them): one asserting `open` probes `_graph_commits.lance` (the exists-gate this commit removes) — it was masked earlier by a disk-full link failure. - Corrected src comments referencing deleted code (`migrate_v3_to_v4`, `append_commit`/`append_merge_commit`, the three-internal-table list, the `_graph_commits` reconcile owner) in publisher/recovery/optimize/recovery_audit. - Narrowed `set_stamp_for_test` to `cfg(test)` (its only caller is the refusal test) — removes a dead-code warning in the failpoints build. Branch create/delete atomicity improves (single atomic `__manifest` op). No behavior change for reads or branches. Follow-up (separate commit): the now-always-0 `IoCounts::commit_graph_reads` test counter + its `IOTracker`, threaded through ~11 cost-test files. * feat: surface the internal-schema (storage-format) version to operators After stranding storage versioning (a sub-v4 graph is refused on open), operators could only discover the storage-format version by hitting a refusal. Surface it: - `omnigraph version` prints an `internal-schema <N>` line (the binary's CURRENT storage-format version). - `omnigraph snapshot` includes `internal_schema_version` — the GRAPH's per-branch on-disk stamp, read via the new `Omnigraph::internal_schema_version_of`. - `GET /healthz` includes `internal_schema_version` (server-scoped: the binary's CURRENT, alongside `version`/`source_version`). Wire: re-expose `INTERNAL_MANIFEST_SCHEMA_VERSION` as `pub` on `db::manifest`; add `internal_schema_version: u32` to `SnapshotOutput` + `HealthOutput`; `snapshot_payload` takes the per-graph version (the `Snapshot` does not carry it), threaded through the embedded CLI + server snapshot callers. `openapi.json` regenerated (two added int32 properties). Extends the existing healthz / snapshot / version tests. * docs(engine): gate internal-schema version at the graph level; record the per-branch read gap PR reviewers flagged that the open path validates only main's internal-schema stamp, so a branch read could decode a branch stamped outside this binary's range. The stamp is a graph-wide storage-format property (the upgrade path is a whole-graph export/import), so with one binary version every branch is always CURRENT; divergence needs concurrent multi-version writers, an unsupported topology already in one-winner-CAS territory. Gating per-branch would add a second __manifest open per non-main branch read to defend a state we do not support, unearned complexity that regresses the warm-read budget. Keep the graph-level gate, document it at the code site (refuse_if_internal_schema_unsupported), and record the read-only residual hole as a known gap in invariants.md to close only when multi-version write topologies become supported. Also clarify the sub-floor rebuild message to say "export with the older omnigraph binary that created it." No behavior change: HEAD already gated at the graph level. * test(cost): remove the dead commit_graph_reads IO counter Phase B retired _graph_commits.lance / _graph_commit_actors.lance, so no commit-graph dataset is opened and the commit_graph IOTracker term is structurally always 0. Remove IoCounts::commit_graph_reads, its total_reads() term, the commit_graph IOTracker in OpProbes, and the now-dead commit_graph_wrapper field on QueryIoProbes (it had no accessor — nothing ever attached it). Drop the 7 trivially-true assert_eq!(commit_graph_reads, 0) checks in warm_read_cost.rs and the debug-print refs in write_cost{,_s3}.rs. Lineage and actor rows now live in __manifest (RFC-013 Phase 7), so the internal_table_scans_are_flat_in_history gate folds into the single manifest_reads flat-assertion — the manifest scan already covers them. Harness-only; no production runtime impact. * docs: align with the commit-graph retirement + strand storage versioning Update the always-loaded and user-facing docs to match the landed state: graph lineage lives in __manifest, the _graph_commits.lance / _graph_commit_actors.lance tables are retired, and storage is strict-single-version (no in-place migration — a sub-CURRENT graph is refused with an export/import rebuild). Fixed stale claims in invariants.md (the migration/atomicity known-gap entry, the Truth Matrix branch-delete row, the read-path/optimize internal-table scope), lance.md (the migrate_v1_to_v2 PK bullet now reflects init-time set; removed the two deleted v3->v4 migration surface guards), testing.md (dropped the deleted migration failpoint tests; manifest-only internal-table term), writes.md (rewrote the Migration-code section to the strand model), storage.md / maintenance.md / constants.md (retired tables out of the layout, internal-table compaction scope, and the constants cheat-sheet), and AGENTS.md. Marked the retirement DONE in the RFC-013 handoff/roadmap and banner-noted the historical RFC analysis. Added docs/user/operations/upgrade.md (the export/import rebuild recipe) and docs/dev/versioning.md (the four-axis compatibility policy: release lockstep / wire additive / storage strict-single-version / Lance pinned), cross-linked from the audience indexes and the AGENTS.md topic map, and rewrote the in-progress v0.8.0 release note for the strand model + version surfacing. check-agents-md.sh passes (65 links, 62 docs). * test(manifest): cover the v3-refusal→export/import rebuild cycle and branch stamp inheritance Two coverage additions from PR review (P1): (a) sub_current_graph_is_refused_then_rebuilt_via_export_import — the full operator narrative in one flow: load → export → a sub-CURRENT graph (stamp rewound below CURRENT) is refused with the export nudge → fresh init + load(export) → data present and the rebuilt graph opens. The refusal is stamp-only (read before any data), so a stamp-rewound graph is a faithful stand-in for a real older-release graph without a second binary; vector/blob fidelity stays covered by tests/export.rs. (b) branch_inherits_main_internal_schema_stamp — proves a branch cannot diverge from main's stamp under single-binary operation (create_branch forks main's __manifest, the publisher does not re-stamp), which is why the graph-level (main-only) stamp gate is sufficient for supported inputs. A divergent branch stamp needs concurrent multi-version writers, the unsupported topology recorded as a known gap.
2026-06-28 16:49:49 +02:00
This release moves the graph commit lineage into `__manifest` (RFC-013 Phase 7),
retires the two legacy commit-graph datasets, and surfaces the storage-format
version to operators. It is the first release with an internal-schema change since
v0.4.0, and storage is **strict-single-version**: there is no in-place migration —
a graph from an older release is rebuilt via export/import. Read the upgrade notes
before rolling it out.
feat(engine): graph lineage in __manifest — single-source fold, v3→v4 migration, schema-version floor (#299) * docs(rfc-013): bank the #295 spec-review comments as step-5 constraints (§5.1) 3b shipped a minimal WriteTxn{branch,base} and deferred the full §4.1 opener unification (pinned-base opener, shared Session, write-local handle cache, strict-op conflict-timing move) to step 5. The greptile comments on the #295 spec were moot for #298 (none of those constructs were built) but are load-bearing for step 5: (1) the handle cache must be Send+Sync (Mutex, not RefCell); (2) the strict-op timing move needs an explicit retry contract — txn discarded after any commit, retry re-opens a fresh base — which is the SAME contract as the stale-view false-fail (§1d.2); (3) the opener-equivalence test must advance HEAD externally then assert pinned-base, not the trivial HEAD==base. * feat(engine): fold graph lineage into the __manifest publish CAS (RFC-013 Phase 7) Graph lineage no longer lives in a second write to _graph_commits.lance. Each commit's graph_commit + graph_head:<branch> rows now ride the SAME __manifest merge-insert as the table-version rows (one atomic version), and CommitGraph reads its cache from the manifest projection (read_graph_lineage). _graph_commits.lance is no longer written commit rows (it remains only as a Lance branch-ref carrier). Mechanism: a LineageIntent { graph_commit_id (ULID, minted once), branch, actor, merged_parent, created_at } threads through ManifestBatchPublisher::publish. Inside the publisher retry loop the parent is resolved per attempt from the just-loaded branch-scoped manifest (the should_replace_head winner over the visible graph_commit rows — branch-correct by Lance branch isolation; the graph_head row is written for forward-compat + the §7.1 contention point but is not the parent source, so a freshly-forked branch resolves the right fork-point parent). A CAS-conflict retry re-reads the advanced head → correct new parent; the commit_id is stable across retries. Closes two known gaps BY CONSTRUCTION (one write, no second step to fail/ race): - manifest→commit-graph atomicity (no crash window between manifest + lineage), - commit-graph parent under concurrency (no refresh→append TOCTOU; the per-write commit_graph.refresh() is gone). Recovery, branch-merge, and genesis route their lineage through the same CAS (merge: one commit_merge_with_actor; recovery: publish_recovery_commit folds the recovery commit, actor=omnigraph:recovery; genesis rides the init __manifest write). The dead _graph_commits write helpers (append_commit/_merge/_actor) are #[allow(dead_code)] (the actor sidecar table is still enumerated by optimize). Verified (sequential): build clean; the new lineage_projection gate (manifest-only — _graph_commits/_actors have 0 rows; full lineage reconstructs via the projection); branching/merge_truth_table (exhaustive, branch-aware)/composite_flow/point_in_time/ changes/consistency/recovery; failpoints (59, incl. recovery lifecycle + the now-closed atomicity gap); full --workspace. Cost tests REVERT to their pre-fold values (writes +1, write_cost ceiling 80) — the proof of true single-CAS (no extra write). invariants.md marks both gaps CLOSED. PENDING (next stages, this PR): the §7.1 concurrent graph_head one-winner gate (stage 5 — two concurrent same-branch commits, exactly one wins); the stamp bump v4 + migrate_v3_to_v4 backfill + read-only refuse for EXISTING graphs (stage 4); full doc-sync of storage.md/architecture.md/writes.md. * feat(engine): migrate existing v3 graphs to manifest lineage (RFC-013 Phase 7 stage 4) The Phase-7 fold made CommitGraph read lineage from the __manifest projection, so a pre-Phase-7 (internal-schema v3) graph — lineage in _graph_commits.lance, none in __manifest — would read an empty commit DAG. Stage 4 makes existing graphs upgrade seamlessly and not break reads. - Stamp 3 -> 4 + migrate_v3_to_v4: bumps INTERNAL_MANIFEST_SCHEMA_VERSION and adds the 3 => migrate_v3_to_v4 arm. The migration reads this branch's _graph_commits/_actors, emits one graph_commit row per commit + exactly one graph_head:<branch> for the head (should_replace_head winner, deterministic id-sort — no hash-map-order in migration output), merge-inserts into __manifest, then set_stamp(4) LAST. Idempotency guard first (read_graph_lineage non-empty -> just stamp); crash before set_stamp re-enters at v3 and the guard completes it. Does NOT touch the unenforced-PK metadata. Runs per branch: migrate_on_open backfills main; load_publish_state backfills each branch on its first write (root_uri/branch threaded through migrate_internal_schema). - v3-read fallback: CommitGraph version-gates the lineage source — stamp < 4 reads the (re-activated) _graph_commits.lance; >= 4 uses the manifest projection. So a READ-ONLY open of an un-migrated graph reads correct history with no write. Correctness catch: the legacy _graph_commit_actors.lance was never branched, so the fallback reads it FLAT (no branch checkout) while checking out the branch only on the commits dataset. - Read-only stamp-refuse: a ReadOnly open of a FUTURE-stamped graph now refuses with the same upgrade error (future-proofing the next format bump; the write path already refused via migrate_internal_schema). - Docs: storage/architecture/writes/invariants/constants updated to manifest-stored lineage; release note docs/releases/v0.8.0.md (format v4, old writers clean-break, data preserved, upgrade writers first). 6 new tests (v3 backfill, idempotent, v3 read-only fallback, future-stamp refuse in both modes, crash-before-stamp completes, legacy branch+flat-actor read). Full engine suite + failpoints (59) + cargo test --workspace --locked green; check-agents-md passes. * test(engine): graph_head concurrency gate — disjoint same-branch writers form a linear commit DAG (RFC-013 Phase 7) Two (or N) writers committing disjoint tables on one branch still share the mutable `graph_head:<branch>` manifest row, so the only row-level CAS contention is that row. The contract — exactly one writer wins each CAS round; the loser retries inside the publisher, re-resolves its parent off the freshly-advanced head, and re-commits, so every writer lands and the graph_commit DAG stays a single LINEAR chain (no fork) — had no acceptance test. This adds it. - concurrent_disjoint_writes_share_head_and_form_linear_chain: two disjoint writers + distinct LineageIntent, tokio::join!; both commit; the on-disk DAG is genesis -> c -> c' (asserted linear: exactly one genesis, no two commits share a parent, the head is the unique non-parent). - n_concurrent_disjoint_writers_converge_to_one_linear_chain: N=8 disjoint writers each with an app-level retry loop (the publisher's internal budget can be exhausted under contention); all converge to one linear chain of 8. - concurrent_disjoint_writes_form_linear_chain_on_s3: the same race on a real object store (true conditional-put CAS), bucket-gated. Cites both tests from the §7.1 contention note in invariants.md. Test-only; no production change. * perf(engine): fold the lineage parent scan into the publish path's single __manifest scan (RFC-013 P2) Each lineage publish scanned `__manifest` twice: `load_publish_state` read table state via one scan, then `resolve_lineage_rows` did a second full `read_graph_lineage` scan only to find the parent commit. Fold the `graph_commit` extraction into the existing scan. - `read_manifest_scan` gains a `collect_lineage` flag. The publish path (`read_publish_scan`) collects the `graph_commit` rows in the same pass; the table-state hot path leaves them in the forward-compat skip arm, so it never pays the O(commits) lineage JSON decode (it also skips reading the `object_id` column entirely). One shared `decode_graph_commit_row` serves both the folded path and the standalone `read_graph_lineage`, so the two cannot drift. - `resolve_lineage_rows` is now sync and takes the already-parsed rows; the per-attempt re-read is preserved because `load_publish_state` runs once per CAS attempt, so a retry still re-parents off the advanced head. - `load_publish_state` returns a named `LoadedPublishState` instead of a four-tuple; the thin `read_registered_table_locations` / `read_tombstone_versions` accessors fold away. `read_manifest_entries` becomes `#[cfg(test)]`: the fold removes its last production caller, leaving only the test-only namespace module (`db/manifest.rs`: `#[cfg(test)] mod namespace`), so gating it keeps it from becoming dead code in non-test builds. Measured at depth ~5: per-write `__manifest` reads drop 44 -> 26 (total reads 54 -> 36). write_cost.rs gains a `manifest_reads <= 34` sub-ceiling that trips if a publish-path scan is re-added, and its calibration comment is corrected. * test(engine): red — transient legacy-open failure silently completes the v3→v4 migration A pre-Phase-7 (internal schema v3) graph keeps its graph lineage in `_graph_commits.lance`; the v3→v4 internal-schema migration backfills it into `__manifest` and stamps v4. `read_legacy_commit_cache` currently maps EVERY `Dataset::open` error to "no legacy data" (`Err(_) => empty`), so a transient or corrupt open during the one-time migration backfills nothing and still stamps v4 — orphaning the real lineage permanently (the migration runs once; the v3 fallback is then disabled). Add a `migration.v3_to_v4.legacy_open` failpoint that injects a non-not-found Lance error at the legacy open, and a fault-injection regression test in the `failpoints` binary. Against the current swallow the migration completes anyway, so the test fails on its "migration must abort" assertion — the predicted symptom. The fix follows in the next commit. Test support reachable from the `failpoints` integration binary (it compiles the crate without `cfg(test)`): the v3-fixture helpers and a stamp/row-count reader are gated `cfg(any(test, feature = "failpoints"))`, still excluded from release builds. Failpoint tests stay in the integration binary because the fail registry is process-global. * fix(engine): propagate non-not-found legacy-open errors in the v3→v4 migration `read_legacy_commit_cache` mapped EVERY `Dataset::open` error to an empty cache (`Err(_) => empty`) on both the legacy commits dataset and its actor sidecar. The v3→v4 internal-schema migration reads this once before stamping internal-schema v4; a transient or corrupt open therefore backfilled nothing and stamped v4 anyway, orphaning the graph's real lineage permanently (the migration runs once, and the stamp-gated v3 fallback is disabled at v4). This is the "no silent failures" deny-list violation, and realistic on object storage. Both opens now match the not-found variants — Lance maps an object-store NotFound to `DatasetNotFound` — as the benign "no legacy data" / "no authors" signal, and propagate anything else as a loud error. The two arms share the variant contract but carry different rationale (commits-absent is the legitimate empty signal; actor-sidecar-absent is benign, but a corrupt actor open silently wiping authorship before stamping v4 is the same loss hole), commented at each site. Pinned by the `lance_surface_guards.rs::dataset_open_missing_returns_not_found_variant` guard (turns red if a Lance bump changes the absence variant) and greens the fault-injection regression test from the previous commit. * test(engine): cover the per-branch v3→v4 migration against a real Lance branch `seed_legacy_v3_lineage` writes every commit (including the "feature"-tagged one) to MAIN's `_graph_commits.lance` with `manifest_branch` as a mere field, so the production per-branch migration path — `read_legacy_commit_cache` checking out a real Lance branch, and a branch-scoped `__manifest` — was never exercised. Add `seed_legacy_v3_lineage_with_branch`, which forks a real `feature` Lance branch on BOTH `_graph_commits.lance` and `__manifest` (the branch inherits main's stripped v3 state), and a test that migrates the BRANCH and asserts the branch's lineage lands in the BRANCH's `__manifest` (genesis + A + branch commit, `graph_head:feature` → branch commit, parents + actors intact) with main's `__manifest` untouched. This empirically resolves the open question behind the merge robustness work: the fast-path `read_graph_lineage(dataset)` has no `manifest_branch` filter, but `__manifest` is Lance-branched per graph-branch, so a branch reads only its own lineage — the test confirms migrating one branch does not leak into another. No branch filter is needed. * refactor(engine): type the lineage-backfill merge conflict via the publisher classifier `state::merge_lineage_rows` (the v3→v4 lineage backfill's standalone `__manifest` merge-insert) stringified its `execute_reader` error, discarding the Lance variant. Route it through the publisher's `map_lance_publish_error` (now `pub(crate)`) so a concurrent first-open's row-level CAS loss surfaces as the SAME typed `OmniError::Manifest{ details: RowLevelCasContention }` the publisher's own retry consumes — one vocabulary, no raw-Lance matching in the migration. Deliberately NOT unified with `optimize::is_retryable_lance_conflict`: that classifier also matches `CommitConflict`/`RetryableCommitConflict` from the compaction commit path, which a row-level merge-insert never emits. Cross-linked with a comment at both sites. Behavior-preserving: the only path that changes is the error TYPE on a CAS loss (previously an opaque `Lance` string, now a typed conflict); no success/failure outcome changes. The bounded re-open retry that consumes the new type lands next. * test(engine): red — concurrent v3→v4 migrations error instead of converging `migrate_v2_to_v3` is concurrent-runner idempotent by design; v3→v4 regressed it. `merge_lineage_rows` uses `conflict_retries(0)` and `migrate_v3_to_v4` has no app-level retry, so when two processes open the same legacy graph at once the backfill's row-level CAS loser errors the whole open instead of converging. The test opens two `__manifest` handles at the same pre-migration (v3, empty-lineage) HEAD and runs both `migrate_internal_schema` calls under `tokio::join!`, forcing the `graph_head:main` CAS to fire every run. Against the current code the loser fails with `RowLevelCasContention` ("Attempted 0 retries.") — the predicted symptom — so the "both must converge" assertion panics. The bounded re-open retry that makes both converge lands next. * fix(engine): make the v3→v4 lineage backfill converge under concurrent runners `migrate_v2_to_v3` is concurrent-runner idempotent; v3→v4 was not. Two processes (or open-for-write handles) opening the same legacy graph at once both reach the backfill merge, and `merge_lineage_rows`'s `conflict_retries(0)` made the row-level CAS loser error the whole open instead of converging. Two contention points, both now handled all-or-nothing: 1. The backfill merge on `graph_head:<branch>`. Wrap (fast-path re-read → read legacy → merge) in a bounded re-open retry loop: a `RowLevelCasContention` loss re-opens the manifest past the winner's (atomic) commit and re-loops; the fast-path re-read then sees the winner's lineage and stamps. On budget exhaustion it returns a `RowLevelCasContention`-typed error so the publisher's OUTER retry loop completes it. The retry decision reuses the publisher's `is_retryable_publish_conflict` so the two stay in lockstep. 2. The terminal stamp bump. Making the merge loser converge newly lets BOTH runners reach `set_stamp(4)` — an `UpdateConfig` commit on the same key — so the loser gets `lance::Error::IncompatibleTransaction` (NOT a row-level CAS, so the merge loop doesn't catch it). This surfaced only under the concurrent full-suite run, not the isolated test. Both write the SAME value, so the conflict is benign: `commit_v4_stamp_idempotently` re-opens and, if the stamp already reached the target, succeeds; else re-applies (bounded). Greens the race test from the previous commit (3x isolated, 5x full-suite, no flake). The new `IncompatibleTransaction` match is pinned by `lance_surface_guards.rs::lance_error_incompatible_transaction_variant_exists`. * fix(engine): refuse a future internal-schema stamp on the branch read path `load_commit_cache_for_branch` dispatched on the branch's internal-schema stamp — `< CURRENT` to the v3 legacy fallback, `>= CURRENT` to the manifest projection — but never refused a `> CURRENT` branch stamp, so a newer-binary shape would be misread by the projection rather than rejected. Add `refuse_if_stamp_too_new(stamp)` (re-exported `pub(crate)` from `migrations`) right after the branch stamp is read, mirroring the main read path's `refuse_if_internal_schema_too_new`. This is defense-in-depth, not a live hole: migrations run main-first (main migrates on open; each branch on its first write), so main's stamp is always >= every branch's and the main path refuses first. The guard closes the gap if that ordering invariant is ever weakened. Tested by force-stamping a real branch past CURRENT and asserting the branch read refuses with the upgrade error (the test misreads via the projection — returns Ok — without the guard, confirmed by removing it). * docs(rfc-013): record the v3→v4 migration robustness fixes invariants.md Known Gaps: the `migrate_v3_to_v4` entry now states the migration is loud on non-not-found legacy-open errors and concurrent-runner idempotent (bounded re-open retry on the merge CAS + idempotent stamp bump), and that the branch read path refuses a `> CURRENT` stamp. lance.md: note the two new surface guards the migration depends on (`dataset_open_missing_returns_not_found_variant`, `lance_error_incompatible_transaction_variant_exists`). testing.md: note the migration fault-injection test in the failpoints row. * refactor: remove dead code and silence warnings across engine + cluster Dead-code sweep follow-up to the RFC-013 stack. No behavior change. - engine: delete the orphaned `validate_edge_cardinality` — the load path uses `validate_edge_cardinality_with_pending_loader` for every mode (including Overwrite, which it treats as the replacement table image), so the old standalone validator had no caller — and correct its sibling's now-stale doc reference. Gate `TableStore::append_batch` `#[cfg(test)]`: it is the inline- commit residual kept only for recovery test setup, with no non-test caller. - cluster: drop unused imports in `lib.rs`, delete the unused `ClusterStore::payload_display`, and raise `LiveGraphObservation` / `GraphObservationJson` / `PolicyTarget` to `pub(crate)` to match the functions that return them. Both lib crates now build warning-free. * fix(engine): match Lance's typed DatasetAlreadyExists, not the message string The internal create-or-open idempotency fallbacks in `db/commit_graph.rs` and `db/recovery_audit.rs` classified the "already exists" race by `err.to_string().contains("Dataset already exists")` — a Lance display string, not an API contract. A wording change upstream would silently break the fallback (a re-create would error instead of opening the existing table). Match the typed `lance::Error::DatasetAlreadyExists { .. }` variant instead — the same discipline as the v3→v4 migration's not-found classifier — pinned by the new `lance_surface_guards.rs::lance_error_dataset_already_exists_variant_exists` guard so a Lance rename turns red instead of silently regressing. * refactor(engine): consolidate now_micros into one crate::db helper Four `fn now_micros() -> Result<i64>` copies (commit_graph, recovery_audit, graph_coordinator, manifest/graph) had already drifted: three mapped the clock error to `OmniError::manifest("...UNIX_EPOCH...")` while recovery_audit used `OmniError::manifest_internal("...unix epoch...")`. Replace all four with one `pub(crate) fn now_micros()` in `db/mod.rs` (the majority `manifest` variant), and repoint the eight call sites at `crate::db::now_micros()`. No test asserts on the failure message, so unifying the variant is behavior-safe; the timestamp-mapping contract can no longer fork across the rows it stamps. * refactor(engine): drop the dead snapshot param from roll_back_sidecar `roll_back_sidecar` took `snapshot: &Snapshot` only to discard it with `let _ = snapshot;` — rollbacks now always publish (the restored HEAD plus a recovery-commit lineage row), so the snapshot is never read to decide whether to skip a publish. Remove the parameter, the two call-site arguments, and the suppressor. A signature must not advertise inputs it does not consume. The `Snapshot` import stays — `process_sidecar`, `roll_forward_all`, and `record_audit_recovery_rollforward` still take it. * test(engine): red — open_at_branch wedges a branch on a missing commit-graph ref A v4 graph keeps its graph lineage in `__manifest` (RFC-013 Phase 7); the `_graph_commits.lance` branch ref is a derived artifact. An interrupted fork-reclaim or a `cleanup` race can drop that derived ref while the manifest lineage stays intact. Per invariants 7 + 15 a missing derived ref must not fail a logical read of the lineage. This wedge builds a real v4 `feature` branch (its `graph_head:feature` row in `__manifest`), force-deletes ONLY the `_graph_commits.lance` `feature` ref, then asserts the branch reads (`open_at_branch` / list-commits / `merge_base`) succeed from `__manifest` while a write that needs the derived ref (`create_branch`) fails loudly with the typed actionable error. Red against current code: `open_at_branch`'s hard `checkout_branch(branch)?` on the missing ref errors `OmniError::Lance` (Lance "Not found: _graph_commits.lance/tree/feature/_versions"), wedging the logical read. * fix(engine): read manifest lineage independent of the derived _graph_commits ref `CommitGraph::open_at_branch` did a hard `checkout_branch(branch)?` on the `_graph_commits.lance` branch ref before reading lineage — so a missing derived ref (an interrupted fork-reclaim, or a `cleanup` race) wedged the branch's commit-list / merge-base / snapshot resolution even though the lineage is readable from the authoritative `__manifest` (RFC-013 Phase 7). That is a derived/physical artifact failing a logical read — invariants 7 and 15. Make the held commits handle `Option<Dataset>` (mirroring `actor_dataset`). `open_at_branch` and `refresh` check out the derived ref best-effort: a typed not-found (`RefNotFound`/`NotFound`) yields a `None` handle while the read re-syncs from `__manifest`; any other open error still propagates. The manifest existence gate is unchanged — `load_commit_cache_for_branch` keeps its hard `?`, so a truly absent branch still fails loudly at the manifest. `create_branch` (the only writer that forks a ref) and the folded-in version lookup return a loud, actionable error on `None`, deferring repair to `cleanup`'s existing orphan reconciler rather than inlining a write on a read-side refresh. Reads (`head_commit`/`load_commits`/`get_commit`/`merge_base`) never touch the handle. Greens the wedge regression from the preceding commit. * fix(engine): v3→v4 retry loops return retryable contention on exhaustion `commit_v4_stamp_idempotently`'s retry loop used `0..=STAMP_RETRY_BUDGET` (6 iterations) with an `attempt < STAMP_RETRY_BUDGET` guard, so the LAST iteration's `IncompatibleTransaction` fell through to `Err(e) => OmniError::Lance(...)` — stringified, non-retryable — instead of the intended `RowLevelCasContention`, and the post-loop contention return was dead code. The publisher's outer retry only re-runs `is_retryable_publish_conflict`, so under sustained concurrent v3→v4 migration the one-time stamp bump could fail instead of converging, defeating the idempotency the migration is supposed to add. Fix the loop to `0..BUDGET` with an UNGUARDED `IncompatibleTransaction` arm: the retryable variant is always handled inside the loop (re-open + same-value check + retry), so it can never reach the stringifying catch-all, and the post-loop is the SINGLE reachable exhaustion path — the typed `RowLevelCasContention`. The `Err(e)` arm now catches only genuine non-contention errors. Apply the same range alignment to the sibling merge loop in `migrate_v3_to_v4` (behaviorally correct today — its `Err(err)` returns the already-typed contention — but it carried the identical off-by-one structure the stamp loop was copied from; aligning both stops the next copy from re-introducing it). Test-first. The exhaustion path is otherwise near-unreachable — a real concurrent winner stamps the same value, so the re-read returns Ok on the first retry — so a new `migration.v4_stamp.force_incompatible` failpoint forces every stamp attempt to lose, driving exhaustion deterministically. Against the pre-fix loop the new `v4_stamp_exhaustion_returns_retryable_contention` test goes red with `Lance("Incompatible transaction: injected failpoint triggered…")`; with the fix it asserts the typed `RowLevelCasContention`. Found by automated review on #299. * feat(engine): minimum-supported internal-schema floor + retirement tripwire The internal-schema migration chain (`migrate_internal_schema`) had a too-new ceiling but no floor, so every old `migrate_vN_…` arm and the v3 legacy readers it needs stay forever — the pile grows by one migration + readers + tests every schema version. Add `MIN_SUPPORTED_INTERNAL_SCHEMA_VERSION` (1 today, a pure no-op: `read_stamp` floors an absent stamp at 1 and no real graph carries 0) as the oldest stamp this binary opens; raising it is how the chain sheds old code. Collapse the one-sided `refuse_if_stamp_too_new` into `refuse_if_stamp_unsupported` checking both bounds, so the floor lands at all three stamp-enforcement sites — the write-path migrate dispatcher, the read-only open guard, and the branch lineage-read path (`commit_graph.rs`) — via one compiler-enforced rename. A hand-wired floor twin would have had to touch each site, and the branch-read path is easy to miss; one combined guard cannot half-enforce. Rename the read-only wrapper `refuse_if_internal_schema_unsupported` to match. A compile-time tripwire (`const _: () = assert!(LOWEST_REGISTERED_MIGRATION_SOURCE == MIN_SUPPORTED…)`) fails the build if a future floor bump forgets to delete the now-dead migration arm (or vice versa) — stronger than a runtime test, impossible to skip, and it doubles as the use that keeps the mirror const live. Tests: a sub-floor graph is refused in both open modes (twin of `future_stamp_is_refused_in_both_open_modes`); the guard accepts exactly [MIN, CURRENT]. No behavior change for any real graph. The retirement runbook lives on the `MIN_SUPPORTED` doc-comment + invariants.md. * fix(engine): compose migration contention with publisher retry; precise recovery-converge audit commit Three review-surfaced fixes on the RFC-013 Phase 7 path. Publisher retry vs migration contention: `publish()` propagated a `load_publish_state` error fatally via `?`, so a `RowLevelCasContention` surfaced by the v3->v4 migration's exhausted merge/stamp budgets aborted the publish instead of being retried — only `merge_rows` conflicts hit the retry. This contradicted the migration's own design, which returns that typed error EXPECTING the publisher to re-run the load (by which point a concurrent winner has usually finished the migration, so the next scan is a no-op). Route a retryable load error through the same retry path as a retryable `merge_rows` conflict. Regression test (failpoints): a one-shot retryable contention injected into `load_publish_state` now commits via the retry; red without the fix (the write fails with the injected contention). Recovery-converge audit commit id: `converge_or_defer_roll_forward` recorded the branch HEAD as the audit row's `graph_commit_id`, but a concurrent user write can advance `graph_head` past the recovery commit between the winner's publish and this read — attributing the audit to a later, wrong commit. Use the latest `RECOVERY_ACTOR`-authored commit (what `publish_recovery_commit` mints), which is the recovery commit by construction. The audit's actor was already correct (it comes from `sidecar.actor_id`, not the commit). Dead param: drop the unused `snapshot` from `record_audit_recovery_rollforward` (removing the `let _ = snapshot;` suppressor). `storage` stays — it is used to delete the sidecar.
2026-06-25 13:55:34 +02:00
## Graph lineage now lives in `__manifest` (internal schema v4)
The graph commit DAG (commits, parents, merge parents, per-branch heads, and the
authoring actor) is now stored in `__manifest` as `graph_commit` / `graph_head`
rows, written in the **same commit (CAS)** as the table-version rows of a graph
feat(engine): retire commit-graph tables (#311) * docs(dev): write-latency roadmap (validated cost model + layered fix) Records the validated 6-LIST warm-write cost model, the two root causes (un-GC'd _versions/; re-resolving latest by listing), and the layered fix (GC + capture-once reuse), plus how commit-graph-table retirement feeds in. Linked from docs/dev/index.md next to the RFC-013 docs. * feat(engine)!: strand storage versioning — one internal-schema version, no in-place migration Set MIN_SUPPORTED == CURRENT == 4: this binary reads exactly one `__manifest` internal-schema version and refuses any older graph on open with a rebuild-via-export/import message, instead of migrating it in place. Storage format changes become a deliberate cutover, not a permanently-carried in-place migration — the pre-release "complexity must be earned" contract. Delete the entire in-place migration apparatus and everything that existed only to support it: the `migrate_vN` arms + dispatcher + stamp-bump helpers + the schema-version-floor tripwire; `migrate_on_open` (both open modes now refuse); the legacy `_graph_commits.lance` readers + the v3 test fixtures + migration tests + `migration.v3_to_v4.*` failpoints + the two surface guards that pinned Lance variants only the migration matched on; and `state::merge_lineage_rows`. Keep `read_stamp` / `stamp_current_version` / `set_stamp` / `refuse_if_stamp_unsupported` — the seam a future one-shot converter plugs into. `load_commit_cache_for_branch` now reads the `__manifest` projection unconditionally (sub-v4 graphs are refused at open). Adds `sub_current_graph_is_refused_on_open_with_rebuild_hint`. The commit-graph TABLES are still created/used as branch-ref ledgers — their retirement (CommitGraph -> pure `__manifest` projection) is the next commit. BREAKING CHANGE: a graph created by omnigraph <= 0.7.2 (internal schema v3) is refused on open. Rebuild it: `omnigraph export` with the old release, then `omnigraph init` + `omnigraph load` with this one. Data, vectors, and blobs are preserved; commit history and branches are not. * feat(engine)!: retire `_graph_commits.lance` / `_graph_commit_actors.lance` — CommitGraph is a pure `__manifest` projection Since RFC-013 Phase 7, graph lineage lives in `__manifest` (`graph_commit` / `graph_head` rows) and branch authority is `__manifest` (branch create forks it first). The two commit-graph datasets were vestigial: `_graph_commit_actors.lance` was never written or read; `_graph_commits.lance` carried zero commit rows and only mirrored the manifest's branch refs (a deny-list "parallel copy"). Retire both. - `CommitGraph` collapses to a pure projection: drops its Lance dataset handles (`dataset`/`actor_dataset`) and all branch methods; `open`/`open_at_branch`/ `refresh`/`init` open NO dataset, building the cache from `ManifestCoordinator::read_graph_lineage_at`. Removes ~1.4s of cold-open dataset opens. - `graph_coordinator`: `commit_graph` is now non-`Option` (always a valid projection). `branch_create`/`branch_delete` go through `ManifestCoordinator` only — a single atomic op, replacing the two-step manifest-fork + commit-graph-fork + rollback. Deleted `create_commit_graph_branch`, `reclaim_commit_graph_branch`, `ensure_commit_graph_initialized`, and every `storage.exists(_graph_commits.lance)` gate. - `optimize`: dropped `reconcile_commit_graph_orphans` and the two tables from the internal-table compaction set (now `__manifest` only). - `instrumentation`: `INTERNAL_TABLE_DIRS` no longer lists the two tables. - Fresh graphs create neither table; `lineage_projection.rs` now asserts both `.lance` dirs are absent. Deleted the obsolete commit-graph-branch-race failpoint tests + their failpoint names, and updated the `maintenance` optimize tests (one internal table, not three). Review-pass fixes folded in: - Removed two stale `omnigraph.rs` in-source tests the prior run missed (a disk-full link failure masked them): one asserting `open` probes `_graph_commits.lance` (the exists-gate this commit removes) — it was masked earlier by a disk-full link failure. - Corrected src comments referencing deleted code (`migrate_v3_to_v4`, `append_commit`/`append_merge_commit`, the three-internal-table list, the `_graph_commits` reconcile owner) in publisher/recovery/optimize/recovery_audit. - Narrowed `set_stamp_for_test` to `cfg(test)` (its only caller is the refusal test) — removes a dead-code warning in the failpoints build. Branch create/delete atomicity improves (single atomic `__manifest` op). No behavior change for reads or branches. Follow-up (separate commit): the now-always-0 `IoCounts::commit_graph_reads` test counter + its `IOTracker`, threaded through ~11 cost-test files. * feat: surface the internal-schema (storage-format) version to operators After stranding storage versioning (a sub-v4 graph is refused on open), operators could only discover the storage-format version by hitting a refusal. Surface it: - `omnigraph version` prints an `internal-schema <N>` line (the binary's CURRENT storage-format version). - `omnigraph snapshot` includes `internal_schema_version` — the GRAPH's per-branch on-disk stamp, read via the new `Omnigraph::internal_schema_version_of`. - `GET /healthz` includes `internal_schema_version` (server-scoped: the binary's CURRENT, alongside `version`/`source_version`). Wire: re-expose `INTERNAL_MANIFEST_SCHEMA_VERSION` as `pub` on `db::manifest`; add `internal_schema_version: u32` to `SnapshotOutput` + `HealthOutput`; `snapshot_payload` takes the per-graph version (the `Snapshot` does not carry it), threaded through the embedded CLI + server snapshot callers. `openapi.json` regenerated (two added int32 properties). Extends the existing healthz / snapshot / version tests. * docs(engine): gate internal-schema version at the graph level; record the per-branch read gap PR reviewers flagged that the open path validates only main's internal-schema stamp, so a branch read could decode a branch stamped outside this binary's range. The stamp is a graph-wide storage-format property (the upgrade path is a whole-graph export/import), so with one binary version every branch is always CURRENT; divergence needs concurrent multi-version writers, an unsupported topology already in one-winner-CAS territory. Gating per-branch would add a second __manifest open per non-main branch read to defend a state we do not support, unearned complexity that regresses the warm-read budget. Keep the graph-level gate, document it at the code site (refuse_if_internal_schema_unsupported), and record the read-only residual hole as a known gap in invariants.md to close only when multi-version write topologies become supported. Also clarify the sub-floor rebuild message to say "export with the older omnigraph binary that created it." No behavior change: HEAD already gated at the graph level. * test(cost): remove the dead commit_graph_reads IO counter Phase B retired _graph_commits.lance / _graph_commit_actors.lance, so no commit-graph dataset is opened and the commit_graph IOTracker term is structurally always 0. Remove IoCounts::commit_graph_reads, its total_reads() term, the commit_graph IOTracker in OpProbes, and the now-dead commit_graph_wrapper field on QueryIoProbes (it had no accessor — nothing ever attached it). Drop the 7 trivially-true assert_eq!(commit_graph_reads, 0) checks in warm_read_cost.rs and the debug-print refs in write_cost{,_s3}.rs. Lineage and actor rows now live in __manifest (RFC-013 Phase 7), so the internal_table_scans_are_flat_in_history gate folds into the single manifest_reads flat-assertion — the manifest scan already covers them. Harness-only; no production runtime impact. * docs: align with the commit-graph retirement + strand storage versioning Update the always-loaded and user-facing docs to match the landed state: graph lineage lives in __manifest, the _graph_commits.lance / _graph_commit_actors.lance tables are retired, and storage is strict-single-version (no in-place migration — a sub-CURRENT graph is refused with an export/import rebuild). Fixed stale claims in invariants.md (the migration/atomicity known-gap entry, the Truth Matrix branch-delete row, the read-path/optimize internal-table scope), lance.md (the migrate_v1_to_v2 PK bullet now reflects init-time set; removed the two deleted v3->v4 migration surface guards), testing.md (dropped the deleted migration failpoint tests; manifest-only internal-table term), writes.md (rewrote the Migration-code section to the strand model), storage.md / maintenance.md / constants.md (retired tables out of the layout, internal-table compaction scope, and the constants cheat-sheet), and AGENTS.md. Marked the retirement DONE in the RFC-013 handoff/roadmap and banner-noted the historical RFC analysis. Added docs/user/operations/upgrade.md (the export/import rebuild recipe) and docs/dev/versioning.md (the four-axis compatibility policy: release lockstep / wire additive / storage strict-single-version / Lance pinned), cross-linked from the audience indexes and the AGENTS.md topic map, and rewrote the in-progress v0.8.0 release note for the strand model + version surfacing. check-agents-md.sh passes (65 links, 62 docs). * test(manifest): cover the v3-refusal→export/import rebuild cycle and branch stamp inheritance Two coverage additions from PR review (P1): (a) sub_current_graph_is_refused_then_rebuilt_via_export_import — the full operator narrative in one flow: load → export → a sub-CURRENT graph (stamp rewound below CURRENT) is refused with the export nudge → fresh init + load(export) → data present and the rebuilt graph opens. The refusal is stamp-only (read before any data), so a stamp-rewound graph is a faithful stand-in for a real older-release graph without a second binary; vector/blob fidelity stays covered by tests/export.rs. (b) branch_inherits_main_internal_schema_stamp — proves a branch cannot diverge from main's stamp under single-binary operation (create_branch forks main's __manifest, the publisher does not re-stamp), which is why the graph-level (main-only) stamp gate is sufficient for supported inputs. A divergent branch stamp needs concurrent multi-version writers, the unsupported topology recorded as a known gap.
2026-06-28 16:49:49 +02:00
publish. Previously the lineage lived in a separate `_graph_commits.lance` dataset
written after the manifest commit, leaving a narrow window where a crash could land
a manifest version with no matching lineage row. Folding the lineage into the
publish closes that gap by construction: a graph commit and its lineage now land
atomically at one manifest version. The in-memory commit graph is a pure projection
of those manifest rows.
This bumps the `__manifest` internal schema stamp to **v4**.
## The `_graph_commits.lance` / `_graph_commit_actors.lance` tables are retired
With lineage in `__manifest` and branch authority already on the manifest, the two
legacy commit-graph datasets are no longer created, read, or written. A graph this
release creates has neither. This removes two cold-open directory listings per
graph open and simplifies maintenance (`optimize` compacts only `__manifest` among
the internal tables now).
## Strict-single-version storage: rebuild via export/import, no in-place migration
Internal schema v4 is a hard version gate, enforced in **both** directions on every
open (read-write and read-only):
- A graph stamped **below v4** (created by an older release whose storage format
this binary does not read) is refused with a **rebuild-via-export/import**
message. There is no in-place upgrade: export the graph with the older binary,
then `omnigraph init` + `omnigraph load` with this one. Data, vectors, and blobs
are preserved; commit history and branches are not carried over. See the
[upgrade guide](../user/operations/upgrade.md).
- A graph stamped **above v4** (created by a newer release) is refused with an
**`upgrade omnigraph before opening this graph`** error, so an old binary cannot
silently misread a newer format.
This replaces the speculative one-time on-disk migration that earlier drafts of
this release described. The rationale (lower long-term liability than carrying
in-place migration code for a pre-release format) is in
[docs/dev/versioning.md](../dev/versioning.md).
## See the storage-format version
Operators can now read the internal-schema version directly instead of discovering
it through a refusal:
- `omnigraph version` prints an `internal-schema <N>` line (the version this binary
serves).
- `omnigraph snapshot` reports the opened graph's on-disk `internal_schema_version`.
- The server `GET /healthz` response includes `internal_schema_version` (the
binary's served version).
## Upgrade order
Upgrade every binary that touches a graph to v0.8.0 together. A mixed fleet where an
older binary still writes a graph another has stamped v4 is unsupported, as with any
internal-schema bump. To move a pre-v4 graph forward, follow the
[upgrade guide](../user/operations/upgrade.md): export with the old binary, then
`init` + `load` with v0.8.0.