Struct WindowState 

pub struct WindowState {
    pub state: WindowAggState,
    pub window_fn: WindowFn,
    pub published: bool,
}

Fields

state: WindowAggState

window_fn: WindowFn

published: bool

True once Self::aggregate_state has been called on this entry. Guards against a second destructive Accumulator::state read: the method itself errors on second call, and the observer loop in BoundedWindowAggStream::publish_finalized_states uses this as an early-skip so it doesn’t attempt one. Independent of state.is_end, which is a group-closed signal that the pruning path also reads.

Implementations

impl WindowState

pub fn aggregate_state(&mut self) -> Result<Option<Vec<ScalarValue>>>

Accumulator::state if this window function is an aggregate, None otherwise (built-in functions like row_number, rank, lead/lag have no serializable accumulator state).

Accumulator::state takes &mut self and its trait doc calls out that “this function should not be called twice, otherwise it will result in potentially non-deterministic behavior.” Several built-in impls (median, percentile_cont, string_agg, min_max_bytes/min_max_struct) std::mem::take their internal buffers on call — a second call returns empty state, not the same state, so a downstream prefix-merge would silently lose every value the accumulator had ingested.

Enforced at this layer: on first call we set Self::published and return the state; any later call errors rather than performing a destructive re-read.

Trait Implementations

impl Debug for WindowState

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

Formats the value using the given formatter.