Method acquire_scan_guard

nodedb/src/data/executor/core_loop/accessors.rs:25–43

Acquire a scan guard for `(tid, collection)`. Returns `Ok(None)` if no quiesce registry is installed (e.g. in tests) — callers treat that as "scan unconditionally". Returns `Err(Response)` carrying a `NodeDbError::collection_draining` error code when a drain is in progress against the collection.

(
        &self,
        task: &crate::data::executor::task::ExecutionTask,
        tid: u64,
        collection: &str,
    )

    /// carrying a `NodeDbError::collection_draining` error code when
    /// a drain is in progress against the collection.
    pub(in crate::data::executor) fn acquire_scan_guard(
        &self,
        task: &crate::data::executor::task::ExecutionTask,
        tid: u64,
        collection: &str,
    ) -> Result<Option<crate::bridge::quiesce::ScanGuard>, crate::bridge::envelope::Response> {
        let Some(q) = self.quiesce.as_ref() else {
            return Ok(None);
        };
        match q.try_start_scan(tid, collection) {
            Ok(g) => Ok(Some(g)),
            Err(_) => Err(self.response_error(
                task,
                crate::bridge::envelope::ErrorCode::CollectionDraining {
                    collection: collection.to_string(),
                },
            )),
        }
    }

    /// Install the encryption key used for vector checkpoint at-rest encryption.
    ///