Method compact

nodedb-vector/src/collection/lifecycle_compact.rs:15–74

Compact sealed segments by removing tombstoned nodes. Rewrites `surrogate_map` and `multi_doc_map` for every sealed segment so that global ids continue to resolve to the correct surrogate after local-id renumbering.

(&mut self)

    /// segment so that global ids continue to resolve to the correct
    /// surrogate after local-id renumbering.
    pub fn compact(&mut self) -> usize {
        let mut total_removed = 0;
        for seg in &mut self.sealed {
            let base_id = seg.base_id;
            let (removed, id_map) = seg.index.compact_with_map();
            total_removed += removed;
            if removed == 0 {
                continue;
            }

            let segment_end = base_id as u64 + id_map.len() as u64;
            let global_keys: Vec<u32> = self
                .surrogate_map
                .keys()
                .copied()
                .filter(|&k| (k as u64) >= base_id as u64 && (k as u64) < segment_end)
                .collect();
            // Two-phase: remove old entries first, then insert new ones
            // so we don't clobber a freshly-remapped entry with a later
            // tombstone removal.
            let mut new_entries: Vec<(u32, Surrogate)> = Vec::with_capacity(global_keys.len());
            for old_global in &global_keys {
                let surrogate = self.surrogate_map.remove(old_global);
                let old_local = (old_global - base_id) as usize;
                let new_local = id_map[old_local];
                if new_local != u32::MAX
                    && let Some(s) = surrogate
                {
                    new_entries.push((base_id + new_local, s));
                } else if let Some(s) = surrogate {
                    // Tombstoned — drop reverse mapping too.
                    self.surrogate_to_local.remove(&s);
                }
            }
            for (k, s) in new_entries {
                self.surrogate_map.insert(k, s);
                self.surrogate_to_local.insert(s, k);
            }

            // Rewrite multi_doc_map entries for this segment.
            for ids in self.multi_doc_map.values_mut() {
                ids.retain_mut(|vid| {
                    let v = *vid;
                    if (v as u64) >= base_id as u64 && (v as u64) < segment_end {
                        let old_local = (v - base_id) as usize;
                        let new_local = id_map[old_local];
                        if new_local == u32::MAX {
                            false
                        } else {
                            *vid = base_id + new_local;
                            true
                        }
                    } else {
                        true
                    }
                });
            }
        }