* 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.
7.2 KiB
Developer Docs
Audience: contributors, maintainers, and coding agents
This is the contributor-facing entry point. These docs explain architecture, invariants, implementation contracts, test ownership, and upstream Lance constraints. User-facing behavior should still be documented through docs/user/index.md and the relevant public reference docs.
Required For Every Non-Trivial Change
| Need | Read |
|---|---|
| Architectural rules, known gaps, deny-list | invariants.md |
| Versioning & compatibility policy (release / wire / storage / Lance) | versioning.md |
| Upstream Lance source-of-truth index | lance.md |
| Existing test coverage and test placement | testing.md |
Architecture And Storage
| Area | Read |
|---|---|
| System structure, L1/L2 framing, component diagrams | architecture.md |
| On-disk layout, manifest schema, URI behavior | storage.md |
| Direct-publish writes, D2, staged writes, recovery sidecars | writes.md |
| Query execution, mutation execution, loader flow | execution.md |
| Index lifecycle and graph topology indexes | indexes.md |
| Branch and commit internals | branches-commits.md |
| Three-way merge implementation and conflicts | merge.md |
| Diff/change-feed implementation | changes.md |
| Branch protection policy | branch-protection.md |
Language, Runtime, And Boundaries
| Area | Read |
|---|---|
| Schema grammar, catalog, migration planner | schema-language.md |
| Query grammar, IR, lints, mutation restrictions | query-language.md |
Embedding client and @embed integration |
embeddings.md |
| Cedar policy surface and server gating | policy.md |
| Server auth, OpenAPI, endpoint handlers | server.md |
| Error taxonomy and serialization | errors.md |
| Constants and tunables | constants.md |
| Transaction model public contract | transactions.md |
| User-doc coherence cleanup ledger | docs-issues.md |
Project Operations
| Area | Read |
|---|---|
| CI and release workflows | ci.md |
| Install and deployment packaging | install.md, deployment.md |
| Release history | releases/ |
Contribution & Governance
| Area | Read |
|---|---|
| How to contribute (external) | CONTRIBUTING.md |
| Governance model, roles, decision authority | GOVERNANCE.md |
| Public contribution RFC track | rfcs/ |
The docs/rfcs/ track is the public, externally-authorable RFC process. The
maintainer/internal RFCs below (rfc-00N-*.md) are a separate, team-owned
track; don't conflate the two.
Case Studies
Worked write-ups of specific bugs — root cause, fix, and the reasoning that ruled out the tempting-but-wrong alternatives. Read these for the debugging pattern, not just the outcome.
| Area | Read |
|---|---|
| camelCase property filters lowercased at runtime (#283) — two engine→Lance boundaries, two different fixes | bug-case-fix.md |
Active Implementation Plans
Working documents for in-flight feature work. Removed when the work lands.
| Area | Read |
|---|---|
Schema-lint chassis v1 (MR-694) — --allow-data-loss, soft/hard drops |
schema-lint-v1-plan.md |
| Inline + stored queries, request/response envelope, MCP (MR-656 / MR-976 / MR-969) | rfc-001-queries-envelope-mcp.md |
| Config & CLI architecture — layered config, client targeting, file naming (MR-973 / MR-974 / MR-981) | rfc-002-config-cli-architecture.md |
| MCP server surface — full tool parity, stored queries, modular auth (MR-969 / MR-956 / MR-974) | rfc-003-mcp-server-surface.md |
| Future cluster control plane — declarative as-code config, JSON state ledger, reconciler | cluster-config-specs.md, cluster-axioms.md, cluster-config-implementation-spec.md |
| Cluster graph & schema apply — Phase 4 sidecars, roll-forward recovery, approval artifacts | rfc-004-cluster-graph-schema-apply.md |
| Server boots from cluster state — Phase 5 mode switch, applied-revision serving | rfc-005-server-cluster-boot.md |
Per-operator config — ~/.omnigraph/ identity, keyed credentials, named servers (the operator slice of RFC-002) |
rfc-007-operator-config.md |
Deprecate omnigraph.yaml — one concern per config surface; key-by-key migration map and staged retirement |
rfc-008-deprecate-omnigraph-yaml.md |
Unify CLI embedded/remote access paths — parity referee, shared wire-DTO crate, GraphClient trait, declared plane capabilities |
rfc-009-unify-access-paths.md |
| Restructure the CLI around explicit planes — one graph-addressing model, declared capability surface, plane-grouped help (expands RFC-009 Phase 4) | rfc-010-cli-planes-restructure.md |
CLI refactoring — one addressing & config model post-omnigraph.yaml: scope + --graph + derived access path, served-default / privileged-direct, profiles, named queries, capability classifier (completes RFC-008) |
rfc-011-cli-refactoring.md |
Provider-independent embedding configuration — one resolved EmbeddingConfig + sealed provider enum (Gemini/OpenAI/Mock), identity recorded in the schema IR, query-time same-space validation, NFR floor |
rfc-012-embedding-provider-config.md |
Write-path latency — capture-once WriteTxn, version-pinned opens, one GraphPublishAuthority fed declarative PublishPlans, manifest-authoritative lineage, epoch fence, bounded history (compaction + cleanup), and an IO-counted cost contract (iss-write-s3-roundtrip-amplification, iss-991) |
rfc-013-write-path-latency.md |
| RFC-013 handoff — current-state map, latest validation, and concrete next actions for finishing write-path latency and correctness work | handoff-rfc-013-write-path.md |
Write-latency roadmap — validated cost model (the 6-LIST warm-write trace), the two root causes (un-GC'd _versions/; re-resolving latest by listing), and the layered fix (GC + capture-once reuse); how commit-graph-table retirement feeds in |
write-latency-roadmap.md |
Boundary
Developer docs may mention implementation details, stale gaps, upstream Lance blockers, and review rules. User docs should not require that context unless the detail changes the public contract.