nodedb 0.4.0

Local-first, real-time, edge-to-cloud hybrid database for multi-modal workloads
Documentation 
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// SPDX-License-Identifier: BUSL-1.1

//! Per-collection read capture for the distributed read resolvers.

use nodedb_physical::physical_plan::PhysicalPlan;

use crate::types::Lsn;

/// One base collection's read observation from a distributed read whose result
/// is materialized on the coordinator.
///
/// Emitted by BOTH the GATHER path (`resolve::exchange` — one capture per base
/// collection under a root `Exchange{Gather}`, including both sides of a
/// gathered `HashJoin`) and the SHUFFLE path (`resolve::shuffle` /
/// `resolve::shuffle_aggregate` — one per join side). Each carries that
/// collection's own bare full-collection scan plan and the REAL per-collection
/// read-version LSN the gather/producers observed. The record seam re-derives
/// the collection / engine / read key from `scan_plan` (a single-collection
/// scan, so it is NOT collapsed to just the left side the way a `HashJoin` plan
/// is) and stamps the entry at `read_version_lsn`, so the commit-time OCC
/// validator re-homes and revalidates each collection's vshard independently.
/// This closes the serializability hole where a build-side (or non-left)
/// collection never appeared in the read-set and a concurrent write to it went
/// undetected.
pub struct DistributedReadCapture {
    pub scan_plan: PhysicalPlan,
    pub read_version_lsn: Lsn,
}