Struct DagWatermarkTracker 

pub struct DagWatermarkTracker { /* private fields */ }

Vec-indexed O(1) watermark tracker for DAG pipelines.

Propagates watermarks through the DAG using min-semantics: a node’s effective watermark is the minimum of its input sources. Uses pre-allocated vectors for Ring 0 compatibility.

Implementations

impl DagWatermarkTracker

pub fn from_dag(dag: &StreamingDag) -> Self

Builds a watermark tracker from a finalized DAG.

Extracts the adjacency structure and execution order from the DAG for efficient watermark propagation.

pub fn update_watermark(&mut self, source: NodeId, wm: i64) -> &[(NodeId, i64)]

Updates a source node’s watermark and propagates downstream.

Returns a slice of (NodeId, new_watermark) pairs for all nodes whose effective watermark changed as a result of this update. The returned slice is valid until the next call to update_watermark.

pub fn get_watermark(&self, node: NodeId) -> Option<i64>

Returns the current watermark for a node, or None if unset.

pub fn effective_watermark(&self, node: NodeId) -> Option<i64>

Returns the effective watermark for a node (min of its inputs).

For source nodes (no inputs), returns the node’s own watermark. Returns None if any input has not yet received a watermark.

pub fn checkpoint(&self) -> DagWatermarkCheckpoint

Creates a checkpoint of the current watermark state.

pub fn restore(&mut self, checkpoint: &DagWatermarkCheckpoint)

Restores watermark state from a checkpoint.

pub fn slot_count(&self) -> usize

Returns the number of node slots allocated.

Trait Implementations

impl Debug for DagWatermarkTracker

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

Formats the value using the given formatter.