Enum datafusion_physical_plan::aggregates::AggregateMode

pub enum AggregateMode {
    Partial,
    Final,
    FinalPartitioned,
    Single,
    SinglePartitioned,
}

Hash aggregate modes

See Accumulator::state for background information on multi-phase aggregation and how these modes are used.

Variants

Partial

Partial aggregate that can be applied in parallel across input partitions.

This is the first phase of a multi-phase aggregation.

Final

Final aggregate that produces a single partition of output by combining the output of multiple partial aggregates.

This is the second phase of a multi-phase aggregation.

FinalPartitioned

Final aggregate that works on pre-partitioned data.

This requires the invariant that all rows with a particular grouping key are in the same partitions, such as is the case with Hash repartitioning on the group keys. If a group key is duplicated, duplicate groups would be produced

Single

Applies the entire logical aggregation operation in a single operator, as opposed to Partial / Final modes which apply the logical aggregation using two operators.

This mode requires that the input is a single partition (like Final)

SinglePartitioned

Applies the entire logical aggregation operation in a single operator, as opposed to Partial / Final modes which apply the logical aggregation using two operators.

This mode requires that the input is partitioned by group key (like FinalPartitioned)

Implementations

impl AggregateMode

pub fn is_first_stage(&self) -> bool

Checks whether this aggregation step describes a “first stage” calculation. In other words, its input is not another aggregation result and the merge_batch method will not be called for these modes.

Trait Implementations

impl Clone for AggregateMode

fn clone(&self) -> AggregateMode

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for AggregateMode

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

Formats the value using the given formatter.

impl PartialEq for AggregateMode

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for AggregateMode

impl Eq for AggregateMode

impl StructuralPartialEq for AggregateMode