omnigraph/docs/maintenance.md
Ragnor Comerford 05e52f2ee0
recovery: rename composite test, strip ticket references, address review
Three bundled changes:

1. Rename `tests/agent_lifecycle.rs` -> `tests/composite_flow.rs` (and
   the test function). OmniGraph is consumed by both humans and agents
   - naming the test after one audience misframes the library.

2. Strip Linear ticket IDs, PR numbers, bot reviewer names, and
   review-round labels from source, tests, and docs added by this
   branch. Internal traceability belongs in commit messages and PR
   descriptions, not in checked-in artifacts. Upstream
   lance-format/lance issue refs and pre-existing MR-XXX refs in docs
   not touched by this branch are left alone.

3. Two outstanding review findings addressed:
   - `needs_index_work_node` / `needs_index_work_edge`: propagate
     `count_rows` errors instead of `unwrap_or(0)`. Silently treating
     transient I/O failures as "0 rows" risked skipping a table from
     the recovery sidecar pin set that was actually about to be
     modified.
   - `recovery_multi_sidecar_requires_fresh_snapshot_for_correctness`:
     strengthen the assertion to fail when sidecar B classifies under
     a stale snapshot. The new assertion checks post-recovery Lance
     HEAD == v3 (no `Dataset::restore` ran). The previous "sidecar
     deleted + audit rows present" pair passed in both the bug and
     fix paths because both delete the sidecar and write an audit
     row; the differentiator is the post-recovery HEAD. Strengthening
     the assertion exposed an additional nuance: in this overlapping-
     sidecar scenario sidecar B's audit kind is RolledBack (no-op)
     rather than RolledForward, since sidecar A's roll-forward
     publishes Lance HEAD as the new manifest pin (absorbing B's
     work). The docstring now explains why this is correct given
     current `roll_forward_all` semantics.

All workspace tests pass with --features failpoints.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-03 13:56:36 +02:00

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Markdown

# 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.
- **Recovery floor:** `--keep < 3` may garbage-collect Lance versions that the open-time recovery sweep needs as a rollback target (the sweep restores to the manifest-pinned `expected_version`, which is HEAD-1 in the typical Phase B → Phase C drift case). Default `--keep 10` is safe.
## 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.