Play的执行上下文与Scala Global [英] Play's execution contexts vs scala global

问题描述

如何从中执行上下文

import scala.concurrent.ExecutionContext.Implicits.global

不同于Play的执行上下文:

differ from Play's execution contexts:

import play.core.Execution.Implicits.{internalContext, defaultContext}

推荐答案

它们非常不同.

在Play 2.3.x及更高版本中，play.core.Execution.Implicits.internalContext是在尺寸上具有固定限制的ForkJoinPool，由Play内部使用.您永远不要将其用于应用程序代码.从文档中:

In Play 2.3.x and prior, play.core.Execution.Implicits.internalContext is a ForkJoinPool with fixed constraints on size, used internally by Play. You should never use it for your application code. From the docs:

Play内部线程池-Play在内部使用.此线程池中的任何线程都不应执行任何应用程序代码，并且该线程池中也不应进行任何阻塞.可以通过在application.conf中设置internal-threadpool-size来配置其大小，并且默认为可用处理器的数量.

Play Internal Thread Pool - This is used internally by Play. No application code should ever be executed by a thread in this thread pool, and no blocking should ever be done in this thread pool. Its size can be configured by setting internal-threadpool-size in application.conf, and it defaults to the number of available processors.

相反，您将使用play.api.libs.concurrent.Execution.Implicits.defaultContext，它使用ActorSystem.

Instead, you would use play.api.libs.concurrent.Execution.Implicits.defaultContext, which uses an ActorSystem.

在2.4.x中，它们都使用相同的ActorSystem.这意味着Akka将在自己的线程池中分配工作，但是以您不可见的方式(配置除外)进行分配.几个Akka演员可以共享同一线程.

In 2.4.x, they both use the same ActorSystem. This means that Akka will distribute work among its own pool of threads, but in a way that is invisible to you (other than configuration). Several Akka actors can share the same thread.

scala.concurrent.ExecutionContext.Implicits.global是Scala标准库中定义的ExecutionContext.特殊的ForkJoinPool使用blocking方法来处理潜在的阻塞代码，以便在池中生成新线程.您真的不应该在Play应用程序中使用此功能，因为Play无法对其进行控制.如果您不小心的话，它还可能产生很多线程并占用大量内存.

scala.concurrent.ExecutionContext.Implicits.global is an ExecutionContext defined in the Scala standard library. It is a special ForkJoinPool that using the blocking method to handle potentially blocking code in order to spawn new threads in the pool. You really shouldn't use this in a Play application, as Play will have no control over it. It also has the potential to spawn a lot of threads and use a ton of memory, if you're not careful.

我在scala.concurrent.ExecutionContext.Implicits.global的内容. >这个答案.

I've written more about scala.concurrent.ExecutionContext.Implicits.global in this answer.

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