mirror of https://github.com/ModernRelay/omnigraph.git synced 2026-06-09 01:35:18 +02:00

Ragnor Comerford a61e82f47a

MR-794 step 2: docs — runs/invariants/architecture/execution + cleanup

Refresh user-facing and agent-facing docs for the staged-write rewire
and clean up stale Run-state-machine references that survived MR-771.

MR-794-specific updates:
* docs/runs.md — remove "Known limitation: mid-query partial failure"
  section; document the in-memory accumulator + D₂ rule + the
  LoadMode::Overwrite residual.
* docs/invariants.md §VI.25 — flip from aspirational/open to
  upheld for inserts/updates. Within-query read-your-writes is now
  load-bearing for the publisher CAS contract.
* docs/architecture.md — add "Mutation atomicity — in-memory
  accumulator (MR-794)" subsection with per-op flow; refresh the
  engine + state diagrams to drop RunRegistry and add MutationStaging.
* docs/execution.md — rewrite the mutation flow sequence diagram
  for the staged-write path; updated the LoadMode table to call
  out per-mode commit semantics; rewrote load vs ingest.
* docs/query-language.md — document the D₂ parse-time rule.
* docs/errors.md — add the D₂ BadRequest rejection path.
* docs/testing.md — extend the runs.rs row to cover the new MR-794
  contract tests; add the staged_writes.rs row.
* docs/releases/v0.4.1.md (new) — release note covering the rewire,
  test additions, residuals, and files changed.
* AGENTS.md (CLAUDE.md symlink) — update the atomic-per-query
  description and the L2 capability matrix row.

Stale-reference cleanup (MR-771 leftovers):
* docs/storage.md — drop live _graph_runs.lance / _graph_run_actors.lance
  from the layout diagram and prose; mark legacy.
* docs/branches-commits.md — move __run__<id> to a legacy note;
  remove publish_run from the publish-trigger list.
* docs/audit.md — refresh _as API list (drop begin_run_as / publish_run_as);
  legacy RunRecord.actor_id moved to a historical note.
* docs/constants.md — mark run registry / branch-prefix rows as legacy.
* docs/cli.md — replace the legacy omnigraph run * quickstart block
  with omnigraph commit list/show.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

2026-05-01 10:43:19 +02:00

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Branches, Commits, Snapshots

L1 — Lance per-dataset branches

Lance supports branching at the dataset level: a branch is a named lineage of versions, and fork_branch_from_state(source_branch, target_branch, source_version) creates a copy-on-write fork.

L2 — Graph-level branches

OmniGraph builds graph branches on top by branching every sub-table coherently:

branch_create(name) / branch_create_from(target, name) — disallowed name main; fails if branch exists; ensures the schema-apply lock is idle.
branch_list() — returns public branches, filters internal __run__… and __schema_apply_lock__ prefixes.
branch_delete(name) — refuses if there are descendants or active runs on the branch; cleans up owned per-branch fragments.
Lazy forking: a branch only forks a sub-table when that sub-table is first mutated on it. Pure-read branches share fragments with their source.
sync_branch(branch) — re-binds the in-memory handle to the latest head of the branch.

L2 — Commit graph (`db/commit_graph.rs`)

In-memory shape of a graph commit:

GraphCommit {
  graph_commit_id: ULID,
  manifest_branch: Option<String>,
  manifest_version: u64,
  parent_commit_id: Option<String>,
  merged_parent_commit_id: Option<String>,   // populated for merge commits
  actor_id: Option<String>,                  // joined in-memory from _graph_commit_actors.lance, NOT a column on _graph_commits.lance
  created_at: i64 (microseconds since epoch),
}

Storage is split across two Lance datasets (both with stable row IDs):

_graph_commits.lance — every column above except actor_id.
_graph_commit_actors.lance — optional separate (graph_commit_id, actor_id) map, created on demand. The actor_id field above is populated by joining this dataset in-memory at load time.

Notes:

Every successful publish (load / change / merge / schema_apply) appends one commit.
Merge commits have two parents; linear commits have one.
API: list_commits(branch), get_commit(id), head_commit_id_for_branch(branch).

L2 — Snapshots & time travel

snapshot() — current snapshot for the bound branch; cached.
snapshot_of(target) — snapshot at a ReadTarget (branch | snapshot id).
snapshot_at_version(v: u64) — historical snapshot from any manifest version.
entity_at(table_key, id, version) — single-entity time travel without building a full snapshot.
A Snapshot is a (version, HashMap<table_key, SubTableEntry>) — cheap to build, snapshot-isolated cross-table reads.

L2 — Internal system branches

Filtered from branch_list() but visible to internals:

__schema_apply_lock__ — serializes schema migrations.
__run__<run-id> — legacy from the pre-v0.4.0 Run state machine (removed in MR-771). The branch-name guard predicate is_internal_run_branch is kept as defense-in-depth so users cannot create a branch matching the legacy prefix; the filter will be removed once production legacy branches are swept (MR-770).

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