Trait timely::dataflow::operators::delay::Delay

pub trait Delay<G: Scope, D: Data> {
    // Required methods
    fn delay<L: FnMut(&D, &G::Timestamp) -> G::Timestamp + 'static>(
        &self,
        func: L
    ) -> Self;
    fn delay_total<L: FnMut(&D, &G::Timestamp) -> G::Timestamp + 'static>(
        &self,
        func: L
    ) -> Self
       where G::Timestamp: TotalOrder;
    fn delay_batch<L: FnMut(&G::Timestamp) -> G::Timestamp + 'static>(
        &self,
        func: L
    ) -> Self;
}

Methods to advance the timestamps of records or batches of records.

Required Methods

fn delay<L: FnMut(&D, &G::Timestamp) -> G::Timestamp + 'static>( &self, func: L ) -> Self

Advances the timestamp of records using a supplied function.

The function must advance the timestamp; the operator will test that the new timestamp is greater or equal to the old timestamp, and will assert if it is not.

Examples

The following example takes the sequence 0..10 at time 0 and delays each element i to time i.

use timely::dataflow::operators::{ToStream, Delay, Operator};
use timely::dataflow::channels::pact::Pipeline;

timely::example(|scope| {
    (0..10).to_stream(scope)
           .delay(|data, time| *data)
           .sink(Pipeline, "example", |input| {
               input.for_each(|time, data| {
                   println!("data at time: {:?}", time);
               });
           });
});

fn delay_total<L: FnMut(&D, &G::Timestamp) -> G::Timestamp + 'static>( &self, func: L ) -> Self

where G::Timestamp: TotalOrder,

Advances the timestamp of records using a supplied function.

This method is a specialization of delay for when the timestamp is totally ordered. In this case, we can use a priority queue rather than an unsorted list to manage the potentially available timestamps.

Examples

The following example takes the sequence 0..10 at time 0 and delays each element i to time i.

use timely::dataflow::operators::{ToStream, Delay, Operator};
use timely::dataflow::channels::pact::Pipeline;

timely::example(|scope| {
    (0..10).to_stream(scope)
           .delay(|data, time| *data)
           .sink(Pipeline, "example", |input| {
               input.for_each(|time, data| {
                   println!("data at time: {:?}", time);
               });
           });
});

fn delay_batch<L: FnMut(&G::Timestamp) -> G::Timestamp + 'static>( &self, func: L ) -> Self

Advances the timestamp of batches of records using a supplied function.

The operator will test that the new timestamp is greater or equal to the old timestamp, and will assert if it is not. The batch version does not consult the data, and may only view the timestamp itself.

Examples

The following example takes the sequence 0..10 at time 0 and delays each batch (there is just one) to time 1.

use timely::dataflow::operators::{ToStream, Delay, Operator};
use timely::dataflow::channels::pact::Pipeline;

timely::example(|scope| {
    (0..10).to_stream(scope)
           .delay_batch(|time| time + 1)
           .sink(Pipeline, "example", |input| {
               input.for_each(|time, data| {
                   println!("data at time: {:?}", time);
               });
           });
});

Object Safety

This trait is not object safe.

Implementors

impl<G: Scope, D: Data> Delay<G, D> for Stream<G, D>