Struct datafusion_physical_expr::expressions::OrderSensitiveArrayAgg

pub struct OrderSensitiveArrayAgg { /* private fields */ }

Expression for a ARRAY_AGG(ORDER BY) aggregation. When aggregation works in multiple partitions aggregations are split into multiple partitions, then their results are merged. This aggregator is a version of ARRAY_AGG that can support producing intermediate aggregation (with necessary side information) and that can merge aggregations from multiple partitions.

Implementations

impl OrderSensitiveArrayAgg

pub fn new( expr: Arc<dyn PhysicalExpr>, name: impl Into<String>, input_data_type: DataType, order_by_data_types: Vec<DataType>, ordering_req: LexOrdering ) -> Self

Create a new OrderSensitiveArrayAgg aggregate function

Trait Implementations

impl AggregateExpr for OrderSensitiveArrayAgg

fn as_any(&self) -> &dyn Any

Returns the aggregate expression as Any so that it can be downcast to a specific implementation.

fn field(&self) -> Result<Field>

the field of the final result of this aggregation.

fn create_accumulator(&self) -> Result<Box<dyn Accumulator>>

the accumulator used to accumulate values from the expressions. the accumulator expects the same number of arguments as expressions and must return states with the same description as state_fields

fn state_fields(&self) -> Result<Vec<Field>>

the fields that encapsulate the Accumulator’s state the number of fields here equals the number of states that the accumulator contains

fn expressions(&self) -> Vec<Arc<dyn PhysicalExpr>>

expressions that are passed to the Accumulator. Single-column aggregations such as sum return a single value, others (e.g. cov) return many.

fn order_bys(&self) -> Option<&[PhysicalSortExpr]>

Order by requirements for the aggregate function By default it is None (there is no requirement) Order-sensitive aggregators, such as FIRST_VALUE(x ORDER BY y) should implement this

fn name(&self) -> &str

Human readable name such as "MIN(c2)". The default implementation returns placeholder text.

fn groups_accumulator_supported(&self) -> bool

If the aggregate expression has a specialized GroupsAccumulator implementation. If this returns true, [Self::create_groups_accumulator] will be called.

fn create_groups_accumulator(&self) -> Result<Box<dyn GroupsAccumulator>>

Return a specialized GroupsAccumulator that manages state for all groups.

fn reverse_expr(&self) -> Option<Arc<dyn AggregateExpr>>

Construct an expression that calculates the aggregate in reverse. Typically the “reverse” expression is itself (e.g. SUM, COUNT). For aggregates that do not support calculation in reverse, returns None (which is the default value).

fn create_sliding_accumulator(&self) -> Result<Box<dyn Accumulator>>

Creates accumulator implementation that supports retract

impl Debug for OrderSensitiveArrayAgg

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

Formats the value using the given formatter.

impl PartialEq<dyn Any> for OrderSensitiveArrayAgg

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

This method tests for self and other values to be equal, and is used by ==.

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

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