Struct UnionFanIn 

pub struct UnionFanIn {
    pub fan_out: NodeId,
    /* private fields */
}

UnionFanIn (union-fan-in.ts): N branch inputs, one output. fetch k-way-merges the branch fetches with PK dedup (merge_node_streams). push either accumulates (during a fan-out broadcast — the owned model) or does a direct cross-branch dedup (a flipped child pushed while the fan-out is idle). On drain it collapses the accumulation via push_accumulated_changes and forwards the single result.

Fields

fan_out: NodeId

Implementations

impl UnionFanIn

pub fn new( fan_out: NodeId, inputs: Vec<NodeId>, branch_constraints: Vec<Constraint>, schema: Schema, ) -> UnionFanIn

pub fn fetch<'g>( &'g self, g: &'g Graph, req: &FetchRequest, ) -> Box<dyn Iterator<Item = Node<'g>> + 'g>

fetch (union-fan-in.ts:103): k-way merge of the branch fetches in compare_rows order (reverse-aware), deduping consecutive PK-equal rows (a row matched by two branches is yielded once). Drop-clean.

Each branch is fetched through fetch_branch, which merges the branch’s build-time pushable constraint into the request — so an eq(pk) branch seeks the shared source instead of full-scanning it (an OR-branch constraint accumulation, not in the JS, which re-scans per branch).

pub fn push<'g>(&'g self, g: &'g Graph, change: Change<'g>)

push (union-fan-in.ts:116): accumulate during a broadcast (materialize to owned before taking the borrow, so the reentrant relationship fetch in materialize_change_preserving_node never runs while the accumulation is borrowed), else a direct internal change.