omnigraph/docs/maintenance.md

# Maintenance: Optimize & Cleanup

`db/omnigraph/optimize.rs`.

## `optimize_all_tables(db)` — non-destructive

- Lance `compact_files()` on every node + edge table on `main`.
- Rewrites small fragments into fewer large ones; old fragments remain reachable via older manifests.
- Bounded by `OMNIGRAPH_MAINTENANCE_CONCURRENCY` (default 8).
- Returns `[TableOptimizeStats { table_key, fragments_removed, fragments_added, committed }]`.

## `cleanup_all_tables(db, options)` — destructive

- Lance `cleanup_old_versions()` per table.
- Removes manifests (and their unique fragments) older than the retention policy.
- `CleanupPolicyOptions { keep_versions: Option<u32>, older_than: Option<Duration> }` — at least one is required.
- Returns `[TableCleanupStats { table_key, bytes_removed, old_versions_removed }]`.
- CLI guards with `--confirm`; without it, prints a preview line.

## Tombstones

Logical sub-table delete markers in `__manifest`; `tombstone_object_id(table_key, version)` excludes a sub-table version from snapshot reconstruction.

## Internal schema migrations (`db/manifest/migrations.rs`)

Version evolutions of the on-disk `__manifest` shape are reconciled automatically on the first write under a new binary. `INTERNAL_MANIFEST_SCHEMA_VERSION` declares the shape the binary expects; the on-disk stamp `omnigraph:internal_schema_version` (Lance schema-level metadata) records the on-disk shape. The publisher's open-for-write path calls `migrate_internal_schema` before reading state; reads are side-effect-free. No operator action is required for in-place upgrades. See [storage.md → Internal schema versioning](storage.md) for the full mechanism.

A binary opening a manifest stamped at a version *higher* than it knows about refuses to publish with a clear "upgrade omnigraph first" error — old binaries cannot clobber a newer schema.
Refactor AGENTS.md from encyclopedia to map; move spec into docs/ Splits the 990-line AGENTS.md into a 184-line map (architecture, where-to-find index, always-on invariants, capability matrix, maintenance contract) plus 18 new docs/*.md files holding the deep content per topic (storage, schema and query languages, indexes, embeddings, branches/commits, runs, merge, changes, execution, policy, server, CLI reference, audit, errors, CI, constants, v0.3.1 notes). Adds scripts/check-agents-md.sh and a check_agents_md CI job that verifies every docs/ link in AGENTS.md resolves and every doc in the canonical set is linked. CLAUDE.md remains a symlink to AGENTS.md. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com> 2026-04-28 23:31:08 +02:00			`# Maintenance: Optimize & Cleanup`

			`db/omnigraph/optimize.rs`.

			## `optimize_all_tables(db)` — non-destructive

			- Lance `compact_files()` on every node + edge table on `main`.
			`- Rewrites small fragments into fewer large ones; old fragments remain reachable via older manifests.`
			- Bounded by `OMNIGRAPH_MAINTENANCE_CONCURRENCY` (default 8).
			- Returns `[TableOptimizeStats { table_key, fragments_removed, fragments_added, committed }]`.

			## `cleanup_all_tables(db, options)` — destructive

			- Lance `cleanup_old_versions()` per table.
			`- Removes manifests (and their unique fragments) older than the retention policy.`
			- `CleanupPolicyOptions { keep_versions: Option<u32>, older_than: Option<Duration> }` — at least one is required.
			- Returns `[TableCleanupStats { table_key, bytes_removed, old_versions_removed }]`.
			- CLI guards with `--confirm`; without it, prints a preview line.

			`## Tombstones`

			Logical sub-table delete markers in `__manifest`; `tombstone_object_id(table_key, version)` excludes a sub-table version from snapshot reconstruction.
Add internal-schema versioning + auto-migration for __manifest The on-disk shape of `__manifest` is reconciled with the binary via a single stamp + dispatcher in `db/manifest/migrations.rs`: - `INTERNAL_MANIFEST_SCHEMA_VERSION = 2` declares the shape this binary writes. - The on-disk stamp `omnigraph:internal_schema_version` lives in the manifest dataset's schema-level metadata (Lance `update_schema_metadata`). - `migrate_internal_schema(&mut dataset)` walks `match`-arm steps forward from the on-disk stamp until it matches the binary, then returns. Idempotent. - `init_manifest_repo` stamps the current version at creation; the publisher's open-for-write path runs pending migrations before reading state. Reads stay side-effect-free. - Forward-version protection: a stamp higher than the binary's known version triggers a clear "upgrade omnigraph first" error so an old binary cannot clobber a newer schema. Self-heals existing pre-MR-766 deployments by auto-applying the v1→v2 step: the `lance-schema:unenforced-primary-key` annotation on `__manifest.object_id` that engages Lance's row-level CAS at commit time. New repos created via `init` are stamped at v2 immediately and don't need migration. Adding a future on-disk shape change is one constant bump, one match arm in `migrate_internal_schema`, and one test — no new branches in unrelated code paths. Code outside the migration module never inspects the stamp. New tests in `manifest/tests.rs`: - `test_init_stamps_internal_schema_version` - `test_publish_migrates_pre_stamp_manifest_to_current_version` - `test_publish_rejects_manifest_stamped_at_future_version` Docs: `docs/storage.md`, `docs/maintenance.md`, `docs/constants.md` updated per the AGENTS.md maintenance contract. 2026-04-29 11:44:14 +00:00
			## Internal schema migrations (`db/manifest/migrations.rs`)

			Version evolutions of the on-disk `__manifest` shape are reconciled automatically on the first write under a new binary. `INTERNAL_MANIFEST_SCHEMA_VERSION` declares the shape the binary expects; the on-disk stamp `omnigraph:internal_schema_version` (Lance schema-level metadata) records the on-disk shape. The publisher's open-for-write path calls `migrate_internal_schema` before reading state; reads are side-effect-free. No operator action is required for in-place upgrades. See [storage.md → Internal schema versioning](storage.md) for the full mechanism.

			`A binary opening a manifest stamped at a version higher than it knows about refuses to publish with a clear "upgrade omnigraph first" error — old binaries cannot clobber a newer schema.`