Struct PlanCache 

pub struct PlanCache<V: Clone> { /* private fields */ }

A bounded LRU plan cache with schema-version invalidation.

V is typically crate::algebra::Algebra (the optimised plan) but the cache is generic so tests can use String, u32, etc.

use oxirs_arq::plan_cache::PlanCache;

let cache: PlanCache<String> = PlanCache::new(10);
cache.insert(42, "plan-a".to_string());
assert_eq!(cache.get(42).as_deref(), Some("plan-a"));

let (hits, misses, evictions) = cache.stats();
assert_eq!(hits, 1);
assert_eq!(misses, 0);
assert_eq!(evictions, 0);

Implementations

impl<V: Clone> PlanCache<V>

pub fn new(capacity: usize) -> Self

Create a new cache with the given maximum capacity.

pub fn get(&self, key: u64) -> Option<V>

Look up key. Returns a clone of the stored value on a hit, or None on a miss. Updates hit/miss counters and refreshes the LRU position.

pub fn insert(&self, key: u64, value: V)

Insert value under key. If the cache is at capacity, the least-recently-used entry is evicted first.

pub fn invalidate_all(&self)

Remove all entries and bump the schema version.

pub fn stats(&self) -> (u64, u64, u64)

Return (hits, misses, evictions) since construction.

pub fn len(&self) -> usize

Current number of entries in the cache.

pub fn is_empty(&self) -> bool

Returns true when the cache holds no entries.

pub fn schema_version(&self) -> u64

Current schema version (bumped by each invalidate_all call).

Trait Implementations

impl<V: Clone> Clone for PlanCache<V>

fn clone(&self) -> Self

Clone returns a handle that shares the same backing store.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.