Method sweep

nodedb-cluster/src/ghost.rs:144–197

Run anti-entropy sweep. For each ghost stub, the caller must verify against the target shard: 1. Does the target shard acknowledge the node exists? 2. Do any local edges still reference this ghost? `verify_fn` takes (node_id, target_shard) and returns SweepVerdict. The sweeper runs at lowest I/O priority and is rate-limited.

(&mut self, verify_fn: F)

    /// `verify_fn` takes (node_id, target_shard) and returns SweepVerdict.
    /// The sweeper runs at lowest I/O priority and is rate-limited.
    pub fn sweep<F>(&mut self, verify_fn: F) -> SweepReport
    where
        F: Fn(&str, u32) -> SweepVerdict,
    {
        let now_ms = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap_or_default()
            .as_millis() as u64;
        self.last_sweep_ms = now_ms;

        let mut report = SweepReport::default();
        let mut to_purge = Vec::new();

        for (node_id, stub) in &self.stubs {
            report.checked += 1;

            // Fast path: if refcount is already 0, purge without remote check.
            if stub.refcount == 0 {
                to_purge.push(node_id.clone());
                report.purged += 1;
                continue;
            }

            match verify_fn(node_id, stub.target_shard) {
                SweepVerdict::Purge => {
                    to_purge.push(node_id.clone());
                    report.purged += 1;
                }
                SweepVerdict::Keep => {
                    report.kept += 1;
                }
                SweepVerdict::Inconclusive => {
                    report.inconclusive += 1;
                }
            }
        }

        for node_id in to_purge {
            self.stubs.remove(&node_id);
            self.purge_count += 1;
        }

        if report.purged > 0 {
            info!(
                purged = report.purged,
                kept = report.kept,
                inconclusive = report.inconclusive,
                total_ghosts = self.stubs.len(),
                "anti-entropy sweep complete"
            );
        }

        report
    }

    pub fn len(&self) -> usize {
        self.stubs.len()