Struct Metric

pub struct Metric { /* private fields */ }

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));

Implementations

impl Metric

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

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>, ) -> Metric

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

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

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

Trait Implementations

impl Debug for Metric

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

Formats the value using the given formatter.

impl Display for Metric

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

Formats the value using the given formatter.