Hystrix: Latency and Fault Tolerance for Distributed Systems

com.netflix.hystrix
Interface HystrixThreadPool

public interface HystrixThreadPool

ThreadPool used to executed HystrixCommand.run() on separate threads when configured to do so with HystrixCommandProperties.executionIsolationStrategy().

Typically each HystrixCommandGroupKey has its own thread-pool so that any one group of commands can not starve others from being able to run.

A HystrixCommand can be configured with a thread-pool explicitly by injecting a HystrixThreadPoolKey or via the HystrixCommandProperties.executionIsolationThreadPoolKeyOverride() otherwise it will derive a HystrixThreadPoolKey from the injected HystrixCommandGroupKey.

The pool should be sized large enough to handle normal healthy traffic but small enough that it will constrain concurrent execution if backend calls become latent.

For more information see the Github Wiki: https://github.com/Netflix/Hystrix/wiki/Configuration#wiki-ThreadPool and https://github.com/Netflix/Hystrix/wiki/How-it-Works#wiki-Isolation

Method Summary

java.util.concurrent.ThreadPoolExecutor	getExecutor() Implementation of ThreadPoolExecutor.
boolean	isQueueSpaceAvailable() Whether the queue will allow adding an item to it.
void	markThreadCompletion() Mark when a thread completes executing a command.
void	markThreadExecution() Mark when a thread begins executing a command.

Method Detail

getExecutor

java.util.concurrent.ThreadPoolExecutor getExecutor()

Implementation of ThreadPoolExecutor.

Returns:

ThreadPoolExecutor

markThreadExecution

void markThreadExecution()

Mark when a thread begins executing a command.

markThreadCompletion

void markThreadCompletion()

Mark when a thread completes executing a command.

isQueueSpaceAvailable

boolean isQueueSpaceAvailable()

Whether the queue will allow adding an item to it.

This allows dynamic control of the max queueSize versus whatever the actual max queueSize is so that dynamic changes can be done via property changes rather than needing an app restart to adjust when commands should be rejected from queuing up.

Returns:

boolean whether there is space on the queue