Struct mz_persist_client::read::Listen

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pub struct Listen<K: Codec, V: Codec, T, D> {
    handle: ReadHandle<K, V, T, D>,
    watch: StateWatch<K, V, T, D>,
    as_of: Antichain<T>,
    since: Antichain<T>,
    frontier: Antichain<T>,
}
Expand description

An ongoing subscription of updates to a shard.

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§handle: ReadHandle<K, V, T, D>§watch: StateWatch<K, V, T, D>§as_of: Antichain<T>§since: Antichain<T>§frontier: Antichain<T>

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

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async fn new(handle: ReadHandle<K, V, T, D>, as_of: Antichain<T>) -> Self

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pub fn frontier(&self) -> &Antichain<T>

An exclusive upper bound on the progress of this Listen.

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

Attempt to pull out the next values of this subscription.

The returned LeasedBatchPart is appropriate to use with crate::fetch::fetch_leased_part.

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

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

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

Attempt to pull out the next values of this subscription.

The updates received in ListenEvent::Updates should be assumed to be in arbitrary order and not necessarily consolidated. However, the timestamp of each individual update will be greater than or equal to the last received ListenEvent::Progress frontier (or this Listen’s initial as_of frontier if no progress event has been emitted yet) and less than the next ListenEvent::Progress frontier.

If you have a use for consolidated listen output, given that snapshots can’t be consolidated, come talk to us!

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pub fn into_stream( self, ) -> impl Stream<Item = ListenEvent<T, ((Result<K, String>, Result<V, String>), T, D)>>

Convert listener into futures::Stream

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

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

Fetches the contents of part and returns its lease.

This is broken out into its own function to provide a trivial means for Subscribe, which contains a Listen, to fetch batches.

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pub async fn expire(self)

Politely expires this listen, releasing its lease.

There is a best-effort impl in Drop for ReadHandle to expire the ReadHandle held by the listen 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§

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

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

Formats the value using the given formatter. Read more

Auto Trait Implementations§

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impl<K, V, T, D> Freeze for Listen<K, V, T, D>
where T: Freeze,

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impl<K, V, T, D> !RefUnwindSafe for Listen<K, V, T, D>

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impl<K, V, T, D> Send for Listen<K, V, T, D>
where T: Send + Sync,

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impl<K, V, T, D> Sync for Listen<K, V, T, D>
where T: Sync + Send,

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impl<K, V, T, D> Unpin for Listen<K, V, T, D>
where T: Unpin,

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impl<K, V, T, D> !UnwindSafe for Listen<K, V, T, D>

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T, U> CastInto<U> for T
where U: CastFrom<T>,

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fn cast_into(self) -> U

Performs the cast.
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> FutureExt for T

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fn with_context(self, otel_cx: Context) -> WithContext<Self>

Attaches the provided Context to this type, returning a WithContext wrapper. Read more
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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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fn into_request(self) -> Request<T>

Wrap the input message T in a tonic::Request
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impl<Unshared, Shared> IntoShared<Shared> for Unshared
where Shared: FromUnshared<Unshared>,

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fn into_shared(self) -> Shared

Creates a shared type from an unshared type.
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impl<T> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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Dereferences the given pointer. Read more
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Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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type Output = T

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