Module graph 

In-memory entity graph with indexed querying, change tracking, and thread-safe access.

The graph module provides a high-performance entity store optimized for the Haystack read/write/subscribe pattern:

• EntityGraph — The core graph store with entities, indexes, and query engine. Supports bitmap tag indexes, B-tree value indexes, bidirectional ref adjacency, and optional CSR representation for cache-friendly traversal.
• SharedGraph — Thread-safe wrapper (Arc<RwLock<EntityGraph>>) for concurrent access from server handlers, WebSocket watches, and federation sync.
• GraphDiff / DiffOp — Change tracking entries (add/update/remove) stored in a bounded changelog for incremental sync and watch notification.

Submodules

Module	Description
entity_graph	Core EntityGraph with CRUD, filter queries, namespace-aware evaluation
shared	SharedGraph — concurrent read/write access with parking_lot::RwLock
bitmap	TagBitmapIndex — bitset-per-tag for O(popcount) Has/Missing filters
value_index	ValueIndex — B-tree indexes for range queries (temp > 72)
adjacency	RefAdjacency — bidirectional HashMap<SmallVec> for ref edges
csr	CSRAdjacency — Compressed Sparse Row format for read-heavy traversal
columnar	ColumnarStore — struct-of-arrays entity storage for scan-heavy workloads
changelog	GraphDiff / DiffOp — bounded change log with version tracking
query_planner	Two-phase query: bitmap acceleration → AST evaluation on candidates

Re-exports

pub use changelog::ChangelogGap;

pub use changelog::DEFAULT_CHANGELOG_CAPACITY;

pub use changelog::DiffOp;

pub use changelog::GraphDiff;

pub use entity_graph::EntityGraph;

pub use entity_graph::GraphError;

pub use entity_graph::HierarchyNode;

pub use shared::SharedGraph;

pub use snapshot::SnapshotError;

pub use snapshot::SnapshotMeta;

pub use snapshot::SnapshotReader;

pub use snapshot::SnapshotWriter;

pub use subscriber::GraphSubscriber;

Modules

adjacency

bitmap

changelog

columnar

csr

entity_graph

query_planner

shared

snapshot

HLSS v1 binary snapshot format — write/read EntityGraph state to disk.

subscriber

value_index