Struct Keyspace 

pub struct Keyspace { /* private fields */ }

The core key-value store.

All operations are single-threaded per shard — no internal locking. Memory usage is tracked incrementally on every mutation.

Implementations

impl Keyspace

pub fn new() -> Self

Creates a new, empty keyspace with default config (no memory limit).

pub fn with_config(config: ShardConfig) -> Self

Creates a new, empty keyspace with the given config.

pub fn get(&mut self, key: &str) -> Option<Value>

Retrieves the value for key, or None if the key doesn’t exist or has expired.

Expired keys are removed lazily on access. Successful reads update the entry’s last access time for LRU tracking.

pub fn set( &mut self, key: String, value: Bytes, expire: Option<Duration>, ) -> SetResult

Stores a key-value pair. If the key already existed, the old entry (including any TTL) is replaced entirely.

expire sets an optional TTL as a duration from now.

Returns SetResult::OutOfMemory if the memory limit is reached and the eviction policy is NoEviction. With AllKeysLru, this will evict keys to make room before inserting.

pub fn del(&mut self, key: &str) -> bool

Removes a key. Returns true if the key existed (and wasn’t expired).

pub fn exists(&mut self, key: &str) -> bool

Returns true if the key exists and hasn’t expired.

pub fn expire(&mut self, key: &str, seconds: u64) -> bool

Sets an expiration on an existing key. Returns true if the key exists (and the TTL was set), false if the key doesn’t exist.

pub fn ttl(&mut self, key: &str) -> TtlResult

Returns the TTL status for a key, following Redis semantics:

• Seconds(n) if the key has a TTL
• NoExpiry if the key exists without a TTL
• NotFound if the key doesn’t exist

pub fn stats(&self) -> KeyspaceStats

Returns aggregated stats for this keyspace.

All fields are tracked incrementally — this is O(1).

pub fn len(&self) -> usize

Returns the number of live keys.

pub fn is_empty(&self) -> bool

Returns true if the keyspace has no entries.

pub fn expire_sample(&mut self, count: usize) -> usize

Randomly samples up to count keys and removes any that have expired.

Returns the number of keys actually removed. Used by the active expiration cycle to clean up keys that no one is reading.

Trait Implementations

impl Default for Keyspace

fn default() -> Self

Returns the “default value” for a type.