Struct Cache 

pub struct Cache { /* private fields */ }

Cache, in which blocks or blobs are cached in-memory after being retrieved from disk

This speeds up consecutive queries to nearby data, improving read performance for hot data.

Examples

Sharing cache between multiple trees

// Provide 64 MB of cache capacity
let cache = Arc::new(Cache::with_capacity_bytes(64 * 1_000 * 1_000));

let tree1 = Config::new(folder, Default::default(), Default::default()).use_cache(cache.clone()).open()?;
let tree2 = Config::new(folder, Default::default(), Default::default()).use_cache(cache.clone()).open()?;

Implementations

impl Cache

pub fn with_capacity_bytes(bytes: u64) -> Self

Creates a new block cache with roughly n bytes of capacity.

pub fn with_row_cache(self, enabled: bool) -> Self

Enables or disables the row cache (decoded point-read results), returning the cache for builder-style configuration. Off by default; rows share the block cache’s byte capacity when enabled.

pub fn row_cache_enabled(&self) -> bool

Whether the row cache is enabled (see Cache::with_row_cache).

pub fn with_metadata_priority(self, enabled: bool) -> Self

Enables or disables high-priority pinning of index / filter / range-tombstone blocks (see Cache::metadata_priority field docs), returning the cache for builder-style configuration. On by default.

pub fn metadata_priority(&self) -> bool

Whether metadata-block priority pinning is enabled (see Cache::with_metadata_priority).

pub fn size(&self) -> u64

Returns the amount of cached bytes.

pub fn capacity(&self) -> u64

Returns the cache capacity in bytes.