Enum EmitClause 

pub enum EmitClause {
    AfterWatermark,
    OnWindowClose,
    Periodically {
        interval: Box<Expr>,
    },
    OnUpdate,
    Changes,
    Final,
}

Parsed EMIT strategy.

Variants

AfterWatermark

Emit when the watermark passes the window end.

OnWindowClose

Emit only when the window closes; this is distinct from AfterWatermark.

Periodically

Emit intermediate results periodically and final results on watermark.

Fields

interval: Box<Expr>

Parsed interval expression.

OnUpdate

Emit after every state change.

Changes

Emit Z-set changelog weights, including retraction pairs for updates.

Final

Emit only finalized results and drop data arriving after window close.

Implementations

impl EmitClause

pub fn to_emit_strategy(&self) -> Result<EmitStrategy, ParseError>

Errors

Returns ParseError::WindowError if the periodic interval cannot be parsed.

pub fn requires_changelog(&self) -> bool

Whether the strategy can emit retractions.

pub fn is_append_only(&self) -> bool

Whether the strategy produces no retractions.

pub fn requires_watermark(&self) -> bool

Whether output depends on source watermark advancement.

OnWindowClose, Final, and AfterWatermark all depend on watermark advancement to trigger window closure. Without a watermark, timers will never fire and windows will never close.

Trait Implementations

impl Clone for EmitClause

fn clone(&self) -> EmitClause

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EmitClause

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

Formats the value using the given formatter.

impl Display for EmitClause

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

Formats the value using the given formatter.

impl PartialEq for EmitClause

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for EmitClause