Struct Strategy 

pub struct Strategy<T: Element> { /* private fields */ }

A probability distribution over read quorums and over write quorums.

Built by QuorumSystem::strategy, QuorumSystem::uniform_strategy, or QuorumSystem::make_strategy; probabilities always sum to 1.

Implementations

impl<T: Element> Strategy<T>

pub fn quorum_system(&self) -> &QuorumSystem<T>

The quorum system this strategy is for.

pub fn sigma_r(&self) -> &BTreeMap<Quorum<T>, f64>

Read quorum probabilities (they sum to 1).

pub fn sigma_w(&self) -> &BTreeMap<Quorum<T>, f64>

Write quorum probabilities (they sum to 1).

pub fn get_read_quorum(&self) -> HashSet<T>

Sample a read quorum according to the strategy.

pub fn get_write_quorum(&self) -> HashSet<T>

Sample a write quorum according to the strategy.

pub fn load( &self, read_fraction: Option<&Distribution>, write_fraction: Option<&Distribution>, ) -> Result<f64>

Expected load of the busiest node, in fractions of its capacity per operation. Capacity is 1 / load.

Errors

Returns an error if the distribution is invalid.

pub fn capacity( &self, read_fraction: Option<&Distribution>, write_fraction: Option<&Distribution>, ) -> Result<f64>

Expected capacity: operations per unit time the system can serve before its busiest node saturates (1 / load at each fraction).

Errors

Returns an error if the distribution is invalid.

pub fn network_load( &self, read_fraction: Option<&Distribution>, write_fraction: Option<&Distribution>, ) -> Result<f64>

Expected number of nodes contacted per operation.

Errors

Returns an error if the distribution is invalid.

pub fn latency( &self, read_fraction: Option<&Distribution>, write_fraction: Option<&Distribution>, ) -> Result<Duration>

Expected operation latency: for each quorum, the time until its fastest nodes form a quorum, weighted by the strategy.

Errors

Returns an error if the distribution is invalid.

pub fn node_load( &self, node: &Node<T>, read_fraction: Option<&Distribution>, write_fraction: Option<&Distribution>, ) -> Result<f64>

Expected load on node.

Capacities come from the quorum system’s copy of the node, so passing Node::new(id) works. Nodes not in the system have load 0.

Errors

Returns an error if the distribution is invalid.

pub fn node_utilization( &self, node: &Node<T>, read_fraction: Option<&Distribution>, write_fraction: Option<&Distribution>, ) -> Result<f64>

Utilization of node: its load relative to the busiest node.

Errors

Returns an error if the distribution is invalid.

pub fn node_throughput( &self, node: &Node<T>, read_fraction: Option<&Distribution>, write_fraction: Option<&Distribution>, ) -> Result<f64>

Requests per unit time handled by node when the system runs at full capacity.

Errors

Returns an error if the distribution is invalid.

Trait Implementations

impl<T: Clone + Element> Clone for Strategy<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug + Element> Debug for Strategy<T>

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

Formats the value using the given formatter.

impl<T: Element> Display for Strategy<T>

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

Formats the value using the given formatter.