Struct mz_persist_client::read::Subscribe

pub struct Subscribe<K: Codec, V: Codec, T, D> {
    snapshot: Option<Vec<LeasedBatchPart<T>>>,
    listen: Listen<K, V, T, D>,
}

Capable of generating a snapshot of all data at as_of, followed by a listen of all updates.

For more details, see ReadHandle::snapshot and Listen.

Fields

snapshot: Option<Vec<LeasedBatchPart<T>>>

listen: Listen<K, V, T, D>

Implementations

impl<K, V, T, D> Subscribe<K, V, T, D>

where K: Debug + Codec, V: Debug + Codec, T: Timestamp + Lattice + Codec64 + Sync, D: Semigroup + Codec64 + Send + Sync,

fn new( snapshot_parts: Vec<LeasedBatchPart<T>>, listen: Listen<K, V, T, D>, ) -> Self

pub async fn next( &mut self, listen_retry: Option<RetryParameters>, ) -> Vec<ListenEvent<T, LeasedBatchPart<T>>>

Returns a LeasedBatchPart enriched with the proper metadata.

First returns snapshot parts, until they’re exhausted, at which point begins returning listen parts.

The returned Antichain represents the subscription progress as it will be after the returned parts are fetched.

impl<K, V, T, D> Subscribe<K, V, T, D>

where K: Debug + Codec, V: Debug + Codec, T: Timestamp + Lattice + Codec64 + Sync, D: Semigroup + Codec64 + Send + Sync,

pub async fn fetch_next( &mut self, ) -> Vec<ListenEvent<T, ((Result<K, String>, Result<V, String>), T, D)>>

Equivalent to next, but rather than returning a LeasedBatchPart, fetches and returns the data from within it.

pub async fn fetch_batch_part( &mut self, part: LeasedBatchPart<T>, ) -> FetchedPart<K, V, T, D>

Fetches the contents of part and returns its lease.

impl<K, V, T, D> Subscribe<K, V, T, D>

where K: Debug + Codec, V: Debug + Codec, T: Timestamp + Lattice + Codec64 + Sync, D: Semigroup + Codec64 + Send + Sync,

pub async fn expire(self)

Politely expires this subscribe, releasing its lease.

There is a best-effort impl in Drop for ReadHandle to expire the ReadHandle held by the subscribe that wasn’t explicitly expired with this method. When possible, explicit expiry is still preferred because the Drop one is best effort and is dependant on a tokio Handle being available in the TLC at the time of drop (which is a bit subtle). Also, explicit expiry allows for control over when it happens.

Trait Implementations

impl<K: Debug + Codec, V: Debug + Codec, T: Debug, D: Debug> Debug for Subscribe<K, V, T, D>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.