Struct Metric 

pub struct Metric {
    value: MetricValue,
    labels: Vec<Label>,
    partition: Option<usize>,
    metric_type: MetricType,
}

Something that tracks a value of interest (metric) of a DataFusion ExecutionPlan execution.

Typically Metrics are not created directly, but instead are created using MetricBuilder or methods on ExecutionPlanMetricsSet.

use datafusion_physical_plan::metrics::*;

let metrics = ExecutionPlanMetricsSet::new();
assert!(metrics.clone_inner().output_rows().is_none());

// Create a counter to increment using the MetricBuilder
let partition = 1;
let output_rows = MetricBuilder::new(&metrics).output_rows(partition);

// Counter can be incremented
output_rows.add(13);

// The value can be retrieved directly:
assert_eq!(output_rows.value(), 13);

// As well as from the metrics set
assert_eq!(metrics.clone_inner().output_rows(), Some(13));

Fields

value: MetricValue

The value of the metric

labels: Vec<Label>

arbitrary name=value pairs identifying this metric

partition: Option<usize>

To which partition of an operators output did this metric apply? If None then means all partitions.

metric_type: MetricType

Implementations

impl Metric

pub fn new(value: MetricValue, partition: Option<usize>) -> Self

Create a new Metric. Consider using MetricBuilder rather than this function directly.

pub fn new_with_labels( value: MetricValue, partition: Option<usize>, labels: Vec<Label>, ) -> Self

Create a new Metric. Consider using MetricBuilder rather than this function directly.

pub fn with_type(self, metric_type: MetricType) -> Self

Set the type for this metric. Defaults to MetricType::DEV

pub fn with_label(self, label: Label) -> Self

Add a new label to this metric

pub fn labels(&self) -> &[Label]

What labels are present for this metric?

pub fn value(&self) -> &MetricValue

Return a reference to the value of this metric

pub fn value_mut(&mut self) -> &mut MetricValue

Return a mutable reference to the value of this metric

pub fn partition(&self) -> Option<usize>

Return a reference to the partition

pub fn metric_type(&self) -> MetricType

Return the metric type (verbosity level) associated with this metric

Trait Implementations

impl Debug for Metric

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

Formats the value using the given formatter.

impl Display for Metric

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

Formats the value using the given formatter.