org.apache.spark.sql.connector.metric

Interface CustomMetric

All Known Implementing Classes:

CustomAvgMetric, CustomSumMetric

@Evolving
public interface CustomMetric

A custom metric. Data source can define supported custom metrics using this interface. During query execution, Spark will collect the task metrics using CustomTaskMetric and combine the metrics at the driver side. How to combine task metrics is defined by the metric class with the same metric name. When Spark needs to aggregate task metrics, it will internally construct the instance of custom metric class defined in data source by using reflection. Spark requires the class implementing this interface to have a 0-arg constructor.

Since:

3.2.0

Field Summary

Fields

Modifier and Type	Field and Description
static long	initialValue The initial value of this metric.

Method Summary

Modifier and Type	Method and Description
String	aggregateTaskMetrics(long[] taskMetrics) Given an array of task metric values, returns aggregated final metric value.
String	description() Returns the description of custom metric.
String	name() Returns the name of custom metric.

Field Detail

initialValue

static final long initialValue

The initial value of this metric.

See Also:

Constant Field Values

Method Detail

name

String name()

Returns the name of custom metric.

description

String description()

Returns the description of custom metric.

aggregateTaskMetrics

String aggregateTaskMetrics(long[] taskMetrics)

Given an array of task metric values, returns aggregated final metric value.