Package com.influxdb.query.dsl.functions

Class ReduceFlux

java.lang.Object

com.influxdb.query.dsl.Flux

com.influxdb.query.dsl.functions.AbstractParametrizedFlux

com.influxdb.query.dsl.functions.ReduceFlux

All Implemented Interfaces:

Expression, HasImports

public final class ReduceFlux
extends AbstractParametrizedFlux

Reduce aggregates records in each table according to the reducer. See SPEC.

Options

• fn - Function to apply to each record with a reducer object of type 'a. [(r: record, accumulator: 'a) -> 'a]
• identity - an initial value to use when creating a reducer ['a]

Example

 Restrictions restriction = Restrictions.and(
     Restrictions.measurement().equal("cpu"),
     Restrictions.field().equal("usage_system"),
     Restrictions.tag("service").equal("app-server")
 );

 Flux flux = Flux
     .from("telegraf")
     .filter(restriction)
     .range(-12L, ChronoUnit.HOURS)
     .reduce("{ sum: r._value + accumulator.sum }", "{sum: 0.0}");

 Flux flux = Flux
     .from("telegraf")
     .filter(restriction)
     .range(-12L, ChronoUnit.HOURS)
     .reduce()
         .withFunction("{sum: r._value + accumulator.sum,\ncount: accumulator.count + 1.0}")
         .withIdentity("{sum: 0.0, count: 0.0}");
 

Author:

Jakub Bednar (24/02/2020 13:02)

Field Summary

Fields inherited from class com.influxdb.query.dsl.Flux

functionsParameters, imports

Constructor Summary

Constructors

Constructor	Description
ReduceFlux(Flux source)

Method Summary

Modifier and Type	Method	Description
void	collectImports(Set<String> collectedImports)	Collects all imports of the flux.
protected String	operatorName()
ReduceFlux	withFunction(String function)
ReduceFlux	withIdentity(String identity)

Methods inherited from class com.influxdb.query.dsl.functions.AbstractParametrizedFlux

appendActual, beforeAppendOperatorName

Methods inherited from class com.influxdb.query.dsl.Flux

addImport, aggregateWindow, aggregateWindow, arrayFrom, arrayFrom, asVariable, columns, columns, count, count, covariance, covariance, covariance, covariance, covariance, covariance, covariance, covariance, covariance, cumulativeSum, cumulativeSum, cumulativeSum, derivative, derivative, difference, difference, difference, difference, difference, difference, distinct, distinct, drop, drop, drop, drop, duplicate, duplicate, elapsed, elapsed, elapsed, elapsed, expression, fill, fill, filter, filter, first, from, from, from, function, getImports, group, groupBy, groupBy, groupBy, groupExcept, groupExcept, groupExcept, integral, integral, interpolateLinear, interpolateLinear, join, join, keep, keep, keep, keep, last, last, limit, limit, limit, map, map, max, max, mean, mean, min, min, pivot, pivot, pivot, quantile, quantile, quantile, quantile, quantile, range, range, range, range, range, range, range, reduce, reduce, rename, rename, rename, sample, sample, sample, set, set, skew, skew, sort, sort, sort, sort, sort, sort, spread, spread, stddev, stddev, sum, sum, tail, tail, tail, timeShift, timeShift, timeShift, timeShift, to, to, to, to, to, to, to, to, toBool, toDuration, toFloat, toInt, toString, toString, toString, toStringConvert, toTime, toUInt, truncateTimeColumn, union, window, window, window, window, window, window, window, withFunction, withFunctionNamed, withPipedFunction, withPropertyNamed, withPropertyNamed, withPropertyValue, withPropertyValue, withPropertyValueEscaped, yield, yield

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

ReduceFlux

public ReduceFlux(@Nonnull
 Flux source)

Method Details

operatorName

@Nonnull
protected String operatorName()

Specified by:

operatorName in class AbstractParametrizedFlux

Returns:

name of function

withFunction

@Nonnull
public ReduceFlux withFunction(@Nonnull
 String function)

Parameters:

function - Function to apply to each record. Example: "{sum: r._value + accumulator.sum}".

Returns:

this

withIdentity

@Nonnull
public ReduceFlux withIdentity(@Nonnull
 String identity)

Parameters:

identity - An initial value to use when creating a reducer. Example: "{sum: 0.0}".

Returns:

this

collectImports

public void collectImports(@Nonnull
 Set<String> collectedImports)

Description copied from class: Flux

Collects all imports of the flux.

Overrides:

collectImports in class Flux

Parameters:

collectedImports - a set to be filled by the used imports