Enum OrderPattern 

pub enum OrderPattern {
    None,
    SourceSatisfied,
    TopK {
        k: usize,
    },
    WindowLocal,
    PerGroupTopK {
        k: usize,
        partition_columns: Vec<String>,
        rank_type: RankType,
    },
    Unbounded,
}

Classification of ORDER BY pattern for streaming safety.

Variants

None

No ORDER BY present.

SourceSatisfied

Source already satisfies the ordering (elided by DataFusion).

TopK

ORDER BY … LIMIT N — bounded top-K.

Fields

k: usize

Number of top entries to maintain

WindowLocal

ORDER BY inside a windowed aggregation — bounded by window.

PerGroupTopK

ROW_NUMBER() / RANK() / DENSE_RANK() OVER (PARTITION BY … ORDER BY …) WHERE rn <= N.

Fields

k: usize

Per-partition limit

partition_columns: Vec<String>

Partition key columns

rank_type: RankType

Which ranking function was used

Unbounded

Unbounded ORDER BY on an unbounded stream — rejected.

Trait Implementations

impl Clone for OrderPattern

fn clone(&self) -> OrderPattern

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for OrderPattern

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

Formats the value using the given formatter.

impl PartialEq for OrderPattern

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl Eq for OrderPattern

impl StructuralPartialEq for OrderPattern