Struct mz_compute_client::command::ComputeCommandHistory

pub struct ComputeCommandHistory<T = Timestamp> {
    reduced_count: usize,
    commands: Vec<ComputeCommand<T>>,
    dataflow_count: usize,
}

Fields

reduced_count: usize

The number of commands at the last time we compacted the history.

commands: Vec<ComputeCommand<T>>

The sequence of commands that should be applied.

This list may not be “compact” in that there can be commands that could be optimized or removed given the context of other commands, for example compaction commands that can be unified, or dataflows that can be dropped due to allowed compaction.

dataflow_count: usize

The number of dataflows in the compute command history.

Implementations

impl<T: Timestamp> ComputeCommandHistory<T>

pub fn push<V>(&mut self, command: ComputeCommand<T>, peeks: &HashMap<Uuid, V>)

Add a command to the history.

This action will reduce the history every time it doubles while retaining the provided peeks.

pub fn len(&self) -> usize

Obtains the length of this compute command history in number of commands.

pub fn dataflow_count(&self) -> usize

Obtains the number of dataflows in this compute command history.

pub fn reduce(&mut self)

Reduces self.history to a minimal form.

This action not only simplifies the issued history, but importantly reduces the instructions to only reference inputs from times that are still certain to be valid. Commands that allow compaction of a collection also remove certainty that the inputs will be available for times not greater or equal to that compaction frontier.

pub fn retain_peeks<V>(&mut self, peeks: &HashMap<Uuid, V>)

Retain only those peeks present in peeks and discard the rest.

pub fn iter(&self) -> impl Iterator<Item = &ComputeCommand<T>>

Iterate through the contained commands.

Trait Implementations

impl<T: Debug> Debug for ComputeCommandHistory<T>

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

Formats the value using the given formatter.

impl<T> Default for ComputeCommandHistory<T>

fn default() -> Self

Returns the “default value” for a type.