Struct TrivialNthValueAccumulator 

pub struct TrivialNthValueAccumulator {
    n: i64,
    values: VecDeque<ScalarValue>,
    datatype: DataType,
}

Fields

n: i64

The N value.

values: VecDeque<ScalarValue>

Stores entries in the NTH_VALUE result.

datatype: DataType

Data types of the value.

Implementations

impl TrivialNthValueAccumulator

pub fn try_new(n: i64, datatype: &DataType) -> Result<Self>

Create a new order-insensitive NTH_VALUE accumulator based on the given item data type.

fn append_new_data( &mut self, values: &[ArrayRef], fetch: Option<usize>, ) -> Result<()>

Updates state, with the values. Fetch contains missing number of entries for state to be complete None represents all of the new values need to be added to the state.

Trait Implementations

impl Accumulator for TrivialNthValueAccumulator

fn update_batch(&mut self, values: &[ArrayRef]) -> Result<()>

Updates its state with the values. Assumes data in the values satisfies the required ordering for the accumulator (across consecutive batches, not just batch-wise).

fn merge_batch(&mut self, states: &[ArrayRef]) -> Result<()>

Updates the accumulator’s state from an Array containing one or more intermediate values.

fn state(&mut self) -> Result<Vec<ScalarValue>>

Returns the intermediate state of the accumulator, consuming the intermediate state.

fn evaluate(&mut self) -> Result<ScalarValue>

Returns the final aggregate value, consuming the internal state.

fn size(&self) -> usize

Returns the allocated size required for this accumulator, in bytes, including Self.

fn retract_batch( &mut self, _values: &[Arc<dyn Array>], ) -> Result<(), DataFusionError>

Retracts (removed) an update (caused by the given inputs) to accumulator’s state.

fn supports_retract_batch(&self) -> bool

Does the accumulator support incrementally updating its value by removing values.

impl Debug for TrivialNthValueAccumulator

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

Formats the value using the given formatter.