Trait FileMetadataCache 

pub trait FileMetadataCache: CacheAccessor<ObjectMeta, Arc<dyn FileMetadata>, Extra = ObjectMeta> {
    // Required methods
    fn cache_limit(&self) -> usize;
    fn update_cache_limit(&self, limit: usize);
    fn list_entries(&self) -> HashMap<Path, FileMetadataCacheEntry>;
}

Cache for file-embedded metadata.

This cache stores per-file metadata in the form of FileMetadata,

For example, the built in ListingTable uses this cache to avoid parsing Parquet footers multiple times for the same file.

DataFusion provides a default implementation, DefaultFilesMetadataCache, and users can also provide their own implementations to implement custom caching strategies.

See crate::runtime_env::RuntimeEnv for more details.

Required Methods

fn cache_limit(&self) -> usize

Returns the cache’s memory limit in bytes.

fn update_cache_limit(&self, limit: usize)

Updates the cache with a new memory limit in bytes.

fn list_entries(&self) -> HashMap<Path, FileMetadataCacheEntry>

Retrieves the information about the entries currently cached.

Trait Implementations

impl Debug for dyn FileMetadataCache

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

Formats the value using the given formatter.

Implementors

impl FileMetadataCache for DefaultFilesMetadataCache