Enum datafusion_expr::window_state::WindowFrameContext

pub enum WindowFrameContext {
    Rows(Arc<WindowFrame>),
    Range {
        window_frame: Arc<WindowFrame>,
        state: WindowFrameStateRange,
    },
    Groups {
        window_frame: Arc<WindowFrame>,
        state: WindowFrameStateGroups,
    },
}

This object stores the window frame state for use in incremental calculations.

Variants

Rows(Arc<WindowFrame>)

ROWS frames are inherently stateless.

Range

Fields

window_frame: Arc<WindowFrame>

state: WindowFrameStateRange

RANGE frames are stateful, they store indices specifying where the previous search left off. This amortizes the overall cost to O(n) where n denotes the row count.

Groups

Fields

window_frame: Arc<WindowFrame>

state: WindowFrameStateGroups

GROUPS frames are stateful, they store group boundaries and indices specifying where the previous search left off. This amortizes the overall cost to O(n) where n denotes the row count.

Implementations

impl WindowFrameContext

pub fn new( window_frame: Arc<WindowFrame>, sort_options: Vec<SortOptions> ) -> Self

Create a new state object for the given window frame.

pub fn calculate_range( &mut self, range_columns: &[ArrayRef], last_range: &Range<usize>, length: usize, idx: usize ) -> Result<Range<usize>>

This function calculates beginning/ending indices for the frame of the current row.

Trait Implementations

impl Debug for WindowFrameContext

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

Formats the value using the given formatter.