Struct WindowShiftEvaluator 

struct WindowShiftEvaluator {
    shift_offset: i64,
    default_value: ScalarValue,
    ignore_nulls: bool,
    non_null_offsets: VecDeque<usize>,
}

Fields

shift_offset: i64

default_value: ScalarValue

ignore_nulls: bool

non_null_offsets: VecDeque<usize>

Implementations

impl WindowShiftEvaluator

fn is_lag(&self) -> bool

Trait Implementations

impl Debug for WindowShiftEvaluator

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

Formats the value using the given formatter.

impl PartitionEvaluator for WindowShiftEvaluator

fn get_range(&self, idx: usize, n_rows: usize) -> Result<Range<usize>>

If uses_window_frame flag is false. This method is used to calculate required range for the window function during stateful execution.

fn is_causal(&self) -> bool

Get whether evaluator needs future data for its result (if so returns false) or not

fn evaluate( &mut self, values: &[ArrayRef], range: &Range<usize>, ) -> Result<ScalarValue>

Evaluate window function on a range of rows in an input partition.x

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

Evaluate a window function on an entire input partition.

fn supports_bounded_execution(&self) -> bool

Can the window function be incrementally computed using bounded memory?

fn memoize( &mut self, _state: &mut WindowAggState, ) -> Result<(), DataFusionError>

When the window frame has a fixed beginning (e.g UNBOUNDED PRECEDING), some functions such as FIRST_VALUE, LAST_VALUE and NTH_VALUE do not need the (unbounded) input once they have seen a certain amount of input.

fn evaluate_all_with_rank( &self, _num_rows: usize, _ranks_in_partition: &[Range<usize>], ) -> Result<Arc<dyn Array>, DataFusionError>

PartitionEvaluator::evaluate_all_with_rank is called for window functions that only need the rank of a row within its window frame.

fn uses_window_frame(&self) -> bool

Does the window function use the values from the window frame, if one is specified?

fn include_rank(&self) -> bool

Can this function be evaluated with (only) rank