Struct EdgeStore 

pub struct EdgeStore { /* private fields */ }

Storage for graph edges with bidirectional indexing.

Provides O(1) access to edges by ID and O(degree) access to outgoing/incoming edges for any node.

Index Structure (EPIC-019 US-003)

• by_label: Secondary index for O(k) label-based queries
• outgoing_by_label: Composite index (source, label) for O(k) filtered traversal

Implementations

impl EdgeStore

pub fn new() -> Self

Creates a new empty edge store.

pub fn with_capacity(expected_edges: usize, expected_nodes: usize) -> Self

Creates an edge store with pre-allocated capacity for better performance.

Pre-allocating reduces memory reallocation overhead when inserting many edges. With 10M edges, this can reduce peak memory usage by ~2x and improve insert throughput.

Arguments

• expected_edges - Expected number of edges to store
• expected_nodes - Expected number of unique nodes (sources + targets)

Example

// For a graph with ~1M edges and ~100K nodes
let store = EdgeStore::with_capacity(1_000_000, 100_000);

pub fn add_edge(&mut self, edge: GraphEdge) -> Result<()>

Adds an edge to the store.

Creates bidirectional index entries for efficient traversal. Also maintains label-based secondary indices (EPIC-019 US-003).

Errors

Returns Error::EdgeExists if an edge with the same ID already exists.

pub fn add_edge_outgoing_only(&mut self, edge: GraphEdge) -> Result<()>

Adds an edge with only the outgoing index (for cross-shard storage).

Used by ConcurrentEdgeStore when source and target are in different shards. The edge is stored and indexed by source node only.

Errors

Returns Error::EdgeExists if an edge with the same ID already exists.

pub fn add_edge_incoming_only(&mut self, edge: GraphEdge) -> Result<()>

Adds an edge with only the incoming index (for cross-shard storage).

Used by ConcurrentEdgeStore when source and target are in different shards. The edge is stored and indexed by target node only. Note: Label indices are maintained by the source shard in ConcurrentEdgeStore.

Errors

Returns Error::EdgeExists if an edge with the same ID already exists.

pub fn edge_count(&self) -> usize

Returns the total number of edges in the store.

pub fn outgoing_edge_count(&self) -> usize

Returns the count of edges where this shard is the source (for accurate cross-shard counting).

pub fn get_edge(&self, id: u64) -> Option<&GraphEdge>

Gets an edge by its ID.

pub fn get_outgoing(&self, node_id: u64) -> Vec<&GraphEdge>

Gets all outgoing edges from a node.

pub fn get_incoming(&self, node_id: u64) -> Vec<&GraphEdge>

Gets all incoming edges to a node.

pub fn get_outgoing_by_label( &self, node_id: u64, label: &str, ) -> Vec<&GraphEdge>

Gets outgoing edges filtered by label using composite index - O(k) where k = result count.

Uses the outgoing_by_label composite index for fast lookup instead of iterating through all outgoing edges (EPIC-019 US-003).

pub fn get_edges_by_label(&self, label: &str) -> Vec<&GraphEdge>

Gets all edges with a specific label - O(k) where k = result count.

Uses the by_label secondary index for fast lookup (EPIC-019 US-003).

pub fn get_incoming_by_label( &self, node_id: u64, label: &str, ) -> Vec<&GraphEdge>

Gets incoming edges filtered by label.

pub fn contains_edge(&self, edge_id: u64) -> bool

Checks if an edge with the given ID exists.

pub fn len(&self) -> usize

Returns the number of edges in the store.

pub fn is_empty(&self) -> bool

Returns true if the store contains no edges.

pub fn all_edges(&self) -> Vec<&GraphEdge>

Returns all edges in the store.

pub fn remove_edge(&mut self, edge_id: u64)

Removes an edge by ID.

Cleans up all indices: outgoing, incoming, by_label, and outgoing_by_label.

pub fn remove_edge_outgoing_only(&mut self, edge_id: u64)

Removes an edge by ID, only cleaning the outgoing index.

Used by ConcurrentEdgeStore for cross-shard cleanup. Also cleans up label indices since they are maintained by source shard.

pub fn remove_edge_incoming_only(&mut self, edge_id: u64)

Removes an edge by ID, only cleaning the incoming index.

Used by ConcurrentEdgeStore for cross-shard cleanup.

pub fn remove_node_edges(&mut self, node_id: u64)

Removes all edges connected to a node (cascade delete).

Removes both outgoing and incoming edges, cleaning up all indices including label indices (EPIC-019 US-003).

Trait Implementations

impl Debug for EdgeStore

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for EdgeStore

fn default() -> EdgeStore

Returns the “default value” for a type.