Struct PreExistingProbe 

pub struct PreExistingProbe { /* private fields */ }

Snapshot of the committed graph state used to (a) distinguish CREATE from UPDATE in MutationEvents::from_l0_with_probe and (b) populate old_value for vertex and edge mutation events.

Built once per commit. The cheap Self::from_l0_chain scans the writer’s L0Manager (current L0 + pending-flush L0s) — no I/O, runs before the writer write lock is acquired. The richer Self::extend_with_l1 adds an async L1 storage probe for VIDs not found in the L0 chain — closes the gap where a vertex flushed to L1 in a previous commit would otherwise be misclassified as NODE_CREATE on its next mutation. The L1 probe also projects every property column on the target label so the resulting old_value carries the same pre-image fidelity as the L0-chain path. Edge pre-images are captured via the L0 chain’s edge_properties snapshot.

Implementations

impl PreExistingProbe

pub fn from_l0_chain(l0_manager: &L0Manager, tx_l0: &L0Buffer) -> Self

Build a probe by scanning the current L0 + pending-flush L0s for vertices/edges referenced in tx_l0. Properties are cloned from the committed L0 chain.

Only mutations actually present in tx_l0 are probed — keeping the work proportional to the commit’s mutation count rather than to the total graph size.

pub fn pending_l1_candidates(&self, tx_l0: &L0Buffer) -> Vec<(Vid, String)>

Snapshot the (vid, label) pairs that should be probed against L1 storage — VIDs in tx_l0 not already marked pre-existing by the L0 chain. Sync — must run under the tx_l0 read lock. Returned vector is sized by chunked-IN-list quota, ready to hand to Self::extend_with_l1 outside the lock.

pub async fn extend_with_l1( &mut self, candidates: Vec<(Vid, String)>, storage: &StorageManager, )

Extend an existing probe with an L1 storage scan for the supplied (vid, label) candidates (typically the output of Self::pending_l1_candidates). Async — runs outside the tx_l0 read lock.

Groups candidates by label, chunks each group into 1024-VID batches, and issues one scan_vertex_table per chunk with a _vid IN (…) filter — bounded I/O proportional to the commit’s mutation count, not the graph size. For every returned VID, every non-vid column is converted via uni_store::storage::arrow_convert::arrow_to_value and stashed as the pre-image Properties map; this populates the old_value column on NODE_UPDATE / NODE_DELETE events emitted by MutationEvents::from_l0_with_probe for vertices that were only visible after the last L0 flush.

Errors

Per-chunk scan errors are logged and ignored — the L0 probe already captured the high-fidelity subset, so a failed L1 probe degrades to “L1 vertices are misclassified as CREATE” rather than failing the commit.

pub fn vertex_pre_existed(&self, vid: Vid) -> bool

True if vid was visible in committed state before this tx.

pub fn edge_pre_existed(&self, eid: Eid) -> bool

True if eid was visible in committed state before this tx.

pub fn vertex_properties(&self, vid: Vid) -> Option<&Properties>

Borrow the captured pre-image properties for vid, when the vertex pre-existed in committed state. Used by MutationEvents::from_l0_with_probe to populate the properties_old event-row column with the subset of keys any trigger predicate references.

pub fn edge_properties(&self, eid: Eid) -> Option<&Properties>

Borrow the captured pre-image properties for eid, when the edge pre-existed in committed state.

Trait Implementations

impl Default for PreExistingProbe

fn default() -> PreExistingProbe

Returns the “default value” for a type.