Struct BackupReader

pub struct BackupReader {
    versions: RwLock<HashMap<MetaSnapshotId, (PinnedVersion, UnboundedReceiver<PinVersionAction>)>>,
    inflight_request: Mutex<HashMap<MetaSnapshotId, Shared<Pin<Box<dyn Future<Output = Result<PinnedVersion, String>> + Send>>>>>,
    store: ArcSwap<(ObjectStoreMetaSnapshotStorage, (String, String))>,
    refresh_tx: UnboundedSender<u64>,
    object_store_config: ObjectStoreConfig,
}

BackupReader helps to access historical hummock versions, which are persisted in meta snapshots (aka backups).

Fields

versions: RwLock<HashMap<MetaSnapshotId, (PinnedVersion, UnboundedReceiver<PinVersionAction>)>>

inflight_request: Mutex<HashMap<MetaSnapshotId, Shared<Pin<Box<dyn Future<Output = Result<PinnedVersion, String>> + Send>>>>>

store: ArcSwap<(ObjectStoreMetaSnapshotStorage, (String, String))>

refresh_tx: UnboundedSender<u64>

object_store_config: ObjectStoreConfig

Implementations

impl BackupReader

pub async fn new( storage_url: &str, storage_directory: &str, object_store_config: &ObjectStoreConfig, ) -> StorageResult<BackupReaderRef>

fn with_store( store: (ObjectStoreMetaSnapshotStorage, (String, String)), object_store_config: ObjectStoreConfig, ) -> BackupReaderRef

pub async fn unused() -> BackupReaderRef

async fn set_store(&self, config: (String, String)) -> StorageResult<()>

async fn start_manifest_refresher( backup_reader: BackupReaderRef, refresh_rx: UnboundedReceiver<u64>, )

Watches latest manifest id to keep local manifest update to date.

pub fn try_refresh_manifest(self: &BackupReaderRef, min_manifest_id: u64)

pub async fn try_get_hummock_version( self: &BackupReaderRef, table_id: TableId, epoch: u64, ) -> StorageResult<Option<PinnedVersion>>

Tries to get a hummock version eligible for querying epoch. SSTs of the returned version are expected to be guarded by corresponding backup. Otherwise, reading the version may encounter object store error, due to SST absence.

pub async fn watch_config_change(&self, rx: Receiver<SystemParamsReaderRef>)