Function table_key

nodedb/src/engine/kv/engine_helpers.rs:10–12

Key encoding and field extraction helpers for the KV engine. Compute a numeric key for per-collection HashMap lookups. Uses FxHash on `(tenant_id, collection)` to produce a `u64` — zero allocation, O(1). Replaces the old `format!("{tenant_id}:{collection}")` which allocated a String on every call (23% of PUT time was malloc/free).

(tenant_id: u64, collection: &str)

/// O(1). Replaces the old `format!("{tenant_id}:{collection}")` which allocated
/// a String on every call (23% of PUT time was malloc/free).
pub(super) fn table_key(tenant_id: u64, collection: &str) -> u64 {
    super::hash_helpers::fxhash_multi(&[&tenant_id.to_le_bytes(), b":", collection.as_bytes()])
}

/// Construct a composite key for the expiry wheel: "{tenant_id}:{collection}\0{key_bytes}".
/// The null byte separator is safe because collection names can't contain null.