A cheat-sheet table of named constants and tunables with values and area. Layout/ manifest names (MANIFEST_DIR=__manifest, _graph_commits.lance, the removed-legacy _graph_runs.lance/__run__, __schema_apply_lock__), publish internals (PUBLISHER_RETRY_BUDGET=5, INTERNAL_MANIFEST_SCHEMA_VERSION=3, MERGE_STAGE_BATCH_ROWS=8192), maintenance concurrency, runtime caches (graph index cache 8 LRU, Lance memory pool 1 GB), traversal tuning (OMNIGRAPH_EXPAND_INDEXED_MAX_FRONTIER=1024, MAX_HOPS=6, CSR_BUILD_FACTOR=1.5), HTTP body limits (1 MB / 32 MB), and embedding defaults. Closes with a prose explanation of the Expand dispatch cost model — indexed per-hop BTREE vs whole-graph CSR chosen on frontier/|E|/source-count/hops plus index coverage. Read when you need a specific constant's value, an environment-variable default, or the precise Expand traversal dispatch tuning knobs.
Constants & Tunables (cheat sheet)
| Name | Value | Area |
|---|---|---|
MANIFEST_DIR |
__manifest |
manifest layout |
| Commit graph dir | _graph_commits.lance |
commit graph |
| Run registry dir (legacy, removed) | _graph_runs.lance |
inert post-v0.4.0; bytes remain until a prefix-delete primitive lands |
| Run branch prefix (legacy, removed) | __run__ |
swept off __manifest by the internal schema migration; no longer a reserved name |
| Schema apply lock | __schema_apply_lock__ |
schema apply |
| Manifest publisher retry budget | PUBLISHER_RETRY_BUDGET = 5 |
manifest publish |
| Internal manifest schema version | INTERNAL_MANIFEST_SCHEMA_VERSION = 3 |
manifest migrations |
| Merge stage batch | MERGE_STAGE_BATCH_ROWS = 8192 |
merge execution |
| Maintenance concurrency | OMNIGRAPH_MAINTENANCE_CONCURRENCY=8 |
optimize/cleanup |
| Lance blob compaction support | LANCE_SUPPORTS_BLOB_COMPACTION = false |
optimize |
| Graph index cache size | 8 (LRU) |
runtime cache |
| Expand indexed-path frontier ceiling | OMNIGRAPH_EXPAND_INDEXED_MAX_FRONTIER=1024 |
traversal |
| Expand indexed-path hop ceiling | OMNIGRAPH_EXPAND_INDEXED_MAX_HOPS=6 |
traversal |
| Expand CSR-build cost factor | CSR_BUILD_FACTOR = 1.5 |
traversal |
| Expand mode override | OMNIGRAPH_TRAVERSAL_MODE (indexed|csr; unset = cost-based auto) |
traversal |
| Default body limit | 1 MB |
HTTP server |
| Ingest body limit | 32 MB |
HTTP server |
| Default embed provider/model | openai-compatible / openai/text-embedding-3-large |
engine embedding |
| OpenAI-direct embed model | text-embedding-3-large |
engine embedding |
| Gemini-direct embed model | gemini-embedding-2 |
engine embedding |
| Embed deadline | OMNIGRAPH_EMBED_DEADLINE_MS=60000 |
engine embedding |
| Embed timeout | OMNIGRAPH_EMBED_TIMEOUT_MS=30000 |
engine embedding |
| Embed retries | OMNIGRAPH_EMBED_RETRY_ATTEMPTS=4 |
engine embedding |
| Embed retry backoff | OMNIGRAPH_EMBED_RETRY_BACKOFF_MS=200 |
engine embedding |
| LANCE memory pool default | 1 GB (raised in v0.3.0) |
runtime |
Expand traversal dispatch. With OMNIGRAPH_TRAVERSAL_MODE unset, the engine
chooses the indexed (per-hop BTREE) vs CSR (whole-graph in-memory) path with a
cost model over cheap manifest counts (frontier size, |E|, source-vertex count,
hops) plus the index-coverage signal: the indexed path is preferred when its
frontier-relative work beats building the CSR (≈ when hops × frontier is a
small fraction of the source-vertex set), and CSR is preferred for dense/deep
traversals or when the BTREE coverage is degraded and a full scan would be paid
per hop. The two ceilings bound the initial dispatch frontier/hops (beyond
them CSR is always used); they are not a hard per-hop bound — the cost model
estimates total indexed work as ~hops × frontier × fanout, so dense fan-out is
priced toward CSR rather than capped mid-traversal. The override flag forces a path (the auto result is identical either way;
only the path differs).