Struct Limit 

pub struct Limit<'a> { /* private fields */ }

Implementations

impl<'a> Limit<'a>

pub fn new( child: Box<dyn PhysicalOperator + 'a>, offset: u64, limit: Option<u64>, ) -> Self

pub fn with_ties( child: Box<dyn PhysicalOperator + 'a>, offset: u64, limit: u64, keys: Vec<SortKey>, evaluator: SharedExpressionEvaluator<'a>, ) -> Self

Build an ordered FETCH ... WITH TIES boundary. The caller must pass the complete effective ORDER BY key list and a non-null row count.

Trait Implementations

impl PhysicalOperator for Limit<'_>

fn row_schema(&self) -> &RowSchema

Complete logical-to-physical row layout emitted by this operator. Every Batch returned by Self::next must carry this exact schema; operators must reject a child that violates that invariant.

fn output_ordering(&self) -> &[PhysicalOrder]

Leading output ordering known to be preserved by this operator.

fn backward_scan_support(&self) -> BackwardScanSupport

Describe backwards-scan support without changing the operator tree. The default is deliberately conservative so a scrollable cursor freezes the complete output of unclassified plans.

fn open(&mut self) -> ExecResult<()>

fn next(&mut self) -> ExecResult<Option<Batch>>

fn next_direction( &mut self, direction: PhysicalScanDirection, ) -> ExecResult<Option<Batch>>

Pull one directional batch. Native backwards-capable pipelines keep batches to one row so a consumer can reverse direction between adjacent fetches.

fn rewind(&mut self) -> ExecResult<()>

Rewind a native backwards-capable pipeline without recomputing rows held by semantic materialization boundaries.

fn close(&mut self) -> ExecResult<()>

fn schema(&self) -> &[String]

Schema column names in logical output order.

fn estimated_cardinality(&self) -> Option<u64>

Planner/runtime cardinality estimate for choosing physical strategies. None means the operator cannot provide a useful estimate. The value is advisory rather than a correctness bound.

fn consume_into_aggregate( &mut self, _executor: &mut dyn AggregateExecutor, ) -> ExecResult<bool>

Let a leaf consume its native projected rows directly into an aggregate executor. Returning false promises that no input was consumed, so the caller can fall back to ordinary Batch pulls.