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EntryMetadata

liquid_cache::cache

Trait EntryMetadata 

Source 
pub trait EntryMetadata:
    Debug
    + Send
    + Sync {
    // Required method
    fn get_compressor(&self, entry_id: &EntryID) -> Arc<LiquidCompressorStates> ⓘ;

    // Provided methods
    fn add_squeeze_hint(
        &self,
        _entry_id: &EntryID,
        _expression: Arc<CacheExpression>,
    ) { ... }
    fn squeeze_hint(&self, _entry_id: &EntryID) -> Option<Arc<CacheExpression>> { ... }
}
Expand description

Per-entry metadata used by the cache.

This trait covers only the metadata side of the cache: where to find a batch’s compressor and squeeze hints. All actual byte IO goes through the t4::Store held by the cache itself.

Required Methods§

Source

fn get_compressor(&self, entry_id: &EntryID) -> Arc<LiquidCompressorStates> ⓘ

Get the compressor for an entry.

Provided Methods§

Source

fn add_squeeze_hint( &self, _entry_id: &EntryID, _expression: Arc<CacheExpression>, )

Add a squeeze hint for an entry.

Source

fn squeeze_hint(&self, _entry_id: &EntryID) -> Option<Arc<CacheExpression>>

Get the squeeze hint for an entry. If None, the entry will be evicted to disk entirely. If Some, the entry will be squeezed according to the cache expressions previously recorded for this column. For example, if expression is ExtractDate32 { field: Date32Field::Year }, the entry will be squeezed to a crate::liquid_array::SqueezedDate32Array with the year component (Date32 or Timestamp input).

Dyn Compatibility§

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors§