Struct dataflow::source::Timestamper

pub struct Timestamper {
    inner: Arc<RwLock<Timestamp>>,
    sender: Sender<Event<Option<Timestamp>, Result<(Row, Timestamp, Diff), SourceError>>>,
    tick_duration: Duration,
    now: NowFn,
}

A thread-safe transaction manager that is responsible for assigning timestamps to the transactions submitted to the system. Rows can be inserted individually using the insert and delete methods or as part of a bigger transaction.

When a transaction is started using start_tx the internal clock will be frozen and any subsequent rows will be timestamped with the exact same timestamp. The transaction is committed automatically as soon as the transaction object gets dropped.

Fields

inner: Arc<RwLock<Timestamp>>

sender: Sender<Event<Option<Timestamp>, Result<(Row, Timestamp, Diff), SourceError>>>

tick_duration: Duration

now: NowFn

Implementations

impl Timestamper

fn new(
    sender: Sender<Event<Option<Timestamp>, Result<(Row, Timestamp, Diff), SourceError>>>,
    tick_duration: Duration,
    now: NowFn
) -> Self

pub async fn start_tx<'a>(&'a self) -> SourceTransaction<'a>

Start a transaction at a particular point in time. The timestamper will freeze its internal clock while a transaction is active.

pub async fn insert(&self, row: Row) -> Result<()>

Record an insertion of a row

pub async fn delete(&self, row: Row) -> Result<()>

Record a deletion of a row

async fn error(&self, err: SourceError) -> Result<()>

Records an error. After this method is called the source will permanently be in an errored state

async fn tick(&self) -> Result<()>

Attempts to monotonically increase the current timestamp and provides a Progress message to timely.

This method will wait for all current transactions to commit before advancing the clock and will cause any new requests for transactions to wait for the tick to complete before starting. This is due to the write-preferring behaviour of the tokio RwLock.