Struct Cache 

pub struct Cache(/* private fields */);

Implementations

impl Cache

pub fn new_lru_cache(capacity: size_t) -> Cache

Creates an LRU cache with capacity in bytes.

pub fn new_lru_cache_opts(opts: &LruCacheOptions) -> Cache

Creates an LRU cache with custom options.

pub fn new_hyper_clock_cache( capacity: size_t, estimated_entry_charge: size_t, ) -> Cache

Creates a HyperClockCache with capacity in bytes.

HyperClockCache is now generally recommended over LRUCache. See RocksDB’s HyperClockCacheOptions in cache.h for details.

estimated_entry_charge is an optional parameter. When not provided (== 0, recommended and default), an HCC variant with a dynamically-growing table and generally good performance is used. This variant depends on anonymous mmaps so might not be available on all platforms.

If the average “charge” (uncompressed block size) of block cache entries is reasonably predicted and provided here, the most efficient variant of HCC is used. Performance is degraded if the prediction is inaccurate. Prediction could be difficult or impossible with cache-charging features such as WriteBufferManager. The best parameter choice based on a cache in use is roughly given by cache.get_usage() / cache.get_occupancy_count(), though it is better to estimate toward the lower side than the higher side when the ratio might vary.

pub fn get_usage(&self) -> usize

Returns the cache memory usage in bytes.

pub fn get_pinned_usage(&self) -> usize

Returns the pinned memory usage in bytes.

pub fn set_capacity(&mut self, capacity: size_t)

Sets cache capacity in bytes.

Trait Implementations

impl Clone for Cache

fn clone(&self) -> Cache

Returns a duplicate of the value.

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

Performs copy-assignment from source.