Struct ReadSnapshot 

pub struct ReadSnapshot {
    pub store: NodeStore,
    pub catalog: Catalog,
    pub csrs: HashMap<u32, CsrForward>,
    pub db_root: PathBuf,
    pub label_row_counts: HashMap<LabelId, usize>,
    /* private fields */
}

Immutable snapshot of storage state required to execute a read query.

Groups the fields that are needed for read-only access to the graph so they can eventually be cloned/shared across parallel executor threads without bundling the mutable per-query state that lives in Engine.

Fields

store: NodeStore

catalog: Catalog

csrs: HashMap<u32, CsrForward>

Per-relationship-type CSR forward files, keyed by RelTableId (u32).

db_root: PathBuf

label_row_counts: HashMap<LabelId, usize>

Cached live node count per label, updated on every node creation.

Used by the planner to estimate cardinality without re-scanning the node store’s high-water-mark file on every query.

Implementations

impl ReadSnapshot

pub fn rel_degree_stats(&self) -> &HashMap<u32, DegreeStats>

Return per-relationship-type out-degree statistics, computing them on first call and caching the result for all subsequent calls.

The CSR forward scan is only triggered once per ReadSnapshot instance, and only when a caller actually needs degree statistics. Queries that never access this (e.g. simple traversals Q3/Q4) pay zero overhead.

pub fn edge_props_for_rel( &self, rel_table_id: u32, ) -> HashMap<(u64, u64), Vec<(u32, u64)>>

Return the cached edge-props map for rel_table_id (SPA-261).