Enum AggregationStrategy 

pub enum AggregationStrategy {
    Hash,
    Sort,
}

Aggregation strategy chosen based on estimated group-key cardinality.

When cardinality metadata is available from segment column statistics, the engine selects the strategy that minimises overhead:

• Hash: O(N) single-pass with FNV-1a hash table. Best for high cardinality (many distinct groups) where sort cost dominates.
• Sort: Sort on group-by columns via Arrow sort_to_indices, then linear scan over contiguous runs. Best for low cardinality where the sort is cheap and avoids hash-table memory overhead. Produces sorted output — advantageous for downstream ORDER BY.

Variants

Hash

FNV-1a hash-table grouping (default).

Sort

Sort group-by columns first, then linear-scan contiguous runs.

Trait Implementations

impl Clone for AggregationStrategy

fn clone(&self) -> AggregationStrategy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for AggregationStrategy

impl Debug for AggregationStrategy

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

Formats the value using the given formatter.

impl Eq for AggregationStrategy

impl PartialEq for AggregationStrategy

fn eq(&self, other: &AggregationStrategy) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for AggregationStrategy