Struct QueryCache 

pub struct QueryCache { /* private fields */ }

Thread-safe LRU cache for server-side query results.

Uses parking_lot::RwLock for efficient concurrent access. Read operations that result in a cache hit still require a write lock (to update LRU order and access counters), but the critical section is kept short.

Implementations

impl QueryCache

pub fn new( max_entries: usize, default_ttl: Duration, max_value_size: usize, ) -> Self

Create a new QueryCache.

Arguments

• max_entries - maximum number of entries the cache may hold.
• default_ttl - default time-to-live for cached entries.
• max_value_size - maximum size (in bytes) of a single cached value.

pub fn get(&self, key: &CacheKey) -> Option<Vec<u8>>

Look up a cached result by cache key.

Returns Some(Vec<u8>) if a non-expired entry exists, otherwise None. On a hit the entry is promoted to most-recently-used and the hit counter is incremented. On a miss or expiry the miss counter is incremented.

pub fn put(&self, key: CacheKey, result: Vec<u8>)

Store a query result in the cache using the cache’s default TTL.

If the value exceeds max_value_size it is silently rejected. If the cache is at capacity the least recently used entry is evicted first.

pub fn put_with_ttl(&self, key: CacheKey, result: Vec<u8>, ttl: Duration)

Store a query result with an explicit TTL and optional collection name.

pub fn put_with_options( &self, key: CacheKey, result: Vec<u8>, ttl: Duration, collection: Option<&str>, )

Store a query result with an explicit TTL and collection name.

pub fn invalidate(&self, collection: &str)

Invalidate all entries belonging to the given collection.

This is the primary write-through invalidation hook: when a PUT, DELETE, or UPDATE operation mutates a collection, call this method with the collection name to ensure stale results are never served.

pub fn invalidate_all(&self)

Clear the entire cache.

pub fn stats(&self) -> CacheStatsSnapshot

Return a snapshot of the current cache statistics.

pub fn resize(&self, new_max: usize)

Resize the cache to a new maximum number of entries.

If the new maximum is smaller than the current number of entries the least recently used entries are evicted until the constraint is met.

pub fn len(&self) -> usize

Current number of entries in the cache.

pub fn is_empty(&self) -> bool

Whether the cache is empty.

pub fn total_size_bytes(&self) -> usize

Total bytes of all cached values.

Trait Implementations

impl Debug for QueryCache

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

Formats the value using the given formatter.