Package org.apache.solr.util.circuitbreaker

Class MemoryCircuitBreaker

java.lang.Object

org.apache.solr.util.circuitbreaker.CircuitBreaker

org.apache.solr.util.circuitbreaker.MemoryCircuitBreaker

All Implemented Interfaces:

Closeable, AutoCloseable, NamedListInitializedPlugin

public class MemoryCircuitBreaker
extends CircuitBreaker

Tracks the current JVM heap usage and triggers if a moving heap usage average over 30 seconds exceeds the defined percentage of the maximum heap size allocated to the JVM. Once the average memory usage goes below the threshold, it will start allowing queries again.

The memory threshold is defined as a percentage of the maximum memory allocated -- see memThreshold in solrconfig.xml.

Constructor Summary

Constructors

Modifier	Constructor	Description
	MemoryCircuitBreaker()	Creates an instance which averages over 6 samples during last 30 seconds.
protected	MemoryCircuitBreaker(int numSamples, int sampleInterval)	Constructor that allows override of sample interval for which the memory usage is fetched.

Method Summary

Modifier and Type	Method	Description
void	close()
protected long	getAvgMemoryUsage()
String	getErrorMessage()	Get error message when the circuit breaker triggers
boolean	isTripped()	Check if circuit breaker is tripped.
MemoryCircuitBreaker	setThreshold(double thresholdValueInPercentage)

Methods inherited from class org.apache.solr.util.circuitbreaker.CircuitBreaker

getErrorCode, getRequestTypes, init, setRequestTypes

Methods inherited from class java.lang.Object

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

Constructor Detail

MemoryCircuitBreaker

public MemoryCircuitBreaker()

Creates an instance which averages over 6 samples during last 30 seconds.

MemoryCircuitBreaker

protected MemoryCircuitBreaker(int numSamples,
                               int sampleInterval)

Constructor that allows override of sample interval for which the memory usage is fetched. This is provided for testing, not intended for general use because the average metric provider implementation is the same for all instances of the class.

Parameters:

numSamples - number of samples to calculate average for

sampleInterval - interval between each sample

Method Detail

setThreshold

public MemoryCircuitBreaker setThreshold(double thresholdValueInPercentage)

isTripped

public boolean isTripped()

Description copied from class: CircuitBreaker

Check if circuit breaker is tripped.

Specified by:

isTripped in class CircuitBreaker

getAvgMemoryUsage

protected long getAvgMemoryUsage()

getErrorMessage

public String getErrorMessage()

Description copied from class: CircuitBreaker

Get error message when the circuit breaker triggers

Specified by:

getErrorMessage in class CircuitBreaker

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class CircuitBreaker

Throws:

IOException