executor | 易学教程

Java Executors: how can I set task priority?

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Is there a possibility to set priority to tasks which are executed by Executors? I've found some statements in JCIP about it's possible but I cannot find any example and I cannot find anything related in docs. From JCIP: An execution policy specifies the "what, where, when, and how" of task execution, including: ... In what order should tasks be executed (FIFO, LIFO, priority order )? ... UPD : I realized that I asked not exactly what I wanted to ask. What I really wanted is: How to use/emulate setting threads priority (i.e. what was thread.setPriority() ) with executors framework? Currently

Mybatis3.3.x技术内幕（四）：五鼠闹东京之执行器Executor设计原本

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在上一篇博文中，已经分析了Mybatis事务相关的内容，而今天的这篇博文，很多内容都是在方法method内部，与事务无关，所以，建议暂时忘记事务概念，避免搅扰。 Mybatis对数据库的操作，都将委托给执行器Executor来完成，所以，在Mybatis这部电影当中，Executor是绝对的领衔主演。在Mybatis中，SqlSession对数据库的操作，将委托给执行器Executor来完成，而Executor由五鼠组成，分别是：简单鼠SimpleExecutor 、重用鼠ReuseExecutor 、批量鼠BatchExecutor 、缓存鼠CachingExecutor 、无用鼠ClosedExecutor 。 ‍ 1. Executor接口设计与类结构图 ‍ public interface Executor { ResultHandler NO_RESULT_HANDLER = null; int update(MappedStatement ms, Object parameter) throws SQLException; <E> List<E> query(MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, CacheKey

When should we use Java's Thread over Executor?

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问题 Executor seems like a clean abstraction. When would you want to use Thread directly rather than rely on the more robust executor? 回答1: To give some history, Executors were only added as part of the java standard in Java 1.5. So in some ways Executors can be seen as a new better abstraction for dealing with Runnable tasks. A bit of an over-simplification coming... - Executors are threads done right so use them in preference. 回答2: I use Thread when I need some pull based message processing. E.g

ThreadPoolExecutor Block When Queue Is Full?

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问题 I am trying to execute lots of tasks using a ThreadPoolExecutor. Below is a hypothetical example: def workQueue = new ArrayBlockingQueue<Runnable>(3, false) def threadPoolExecutor = new ThreadPoolExecutor(3, 3, 1L, TimeUnit.HOURS, workQueue) for(int i = 0; i < 100000; i++) threadPoolExecutor.execute(runnable) The problem is that I quickly get a java.util.concurrent.RejectedExecutionException since the number of tasks exceeds the size of the work queue. However, the desired behavior I am

Spark Application、Driver、Job、stage、task

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1、Application 　　application（应用）其实就是用spark-submit提交的程序。一个application通常包含三部分：从数据源（比方说HDFS）取数据形成RDD，通过RDD的transformation和action进行计算，将结果输出到console或者外部存储。 2、Driver 　　Spark中的driver感觉其实和yarn中Application Master的功能相类似。主要完成任务的调度以及和executor和cluster manager进行协调。有client和cluster联众模式。client模式driver在任务提交的机器上运行，而cluster模式会随机选择机器中的一台机器启动driver。通俗讲，driver可以理解为用户自己编写的程序。我们使用spark-submit提交一个Spark作业之后，这个作业就会启动一个对应的Driver进程. 　　Driver进程本身会根据我们设置的参数，占有一定数量的内存和CPU core。而Driver进程要做的第一件事情，就是向集群管理器（常用的如 yarn）申请运行Spark作业需要使用的资源，这里的资源指的就是Executor进程。YARN集群管理器会根据我们为Spark作业设置的资源参数，在各个工作节点上，启动一定数量的Executor进程

spark-圆周率

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计算圆周率： / opt / software / spark / bin / spark - submit -- class org . apache . spark . examples . SparkPi -- master spark : / / node01 : 7077 -- executor - memory 1 G -- total - executor - cores 2 / opt / software / spark / examples / jars / spark - examples_2 . 11 - 2.0 .2 . jar 10 需要先启动spark，在spark的sbin目录下 ./start-all-sh 来源： CSDN 作者：今日份链接： https://blog.csdn.net/weixin_44694973/article/details/96819899

Java Executors: how can I set task priority?

阅读更多关于 Java Executors: how can I set task priority?

问题 Is there a possibility to set priority to tasks which are executed by Executors? I\'ve found some statements in JCIP about it\'s possible but I cannot find any example and I cannot find anything related in docs. From JCIP: An execution policy specifies the \"what, where, when, and how\" of task execution, including: ... In what order should tasks be executed (FIFO, LIFO, priority order )? ... UPD : I realized that I asked not exactly what I wanted to ask. What I really wanted is: How to use

How to make ThreadPoolExecutor's submit() method block if it is saturated?

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I want to create a ThreadPoolExecutor such that when it has reached its maximum size and the queue is full, the submit() method blocks when trying to add new tasks. Do I need to implement a custom RejectedExecutionHandler for that or is there an existing way to do this using a standard Java library? Fixpoint One of the possible solutions I've just found: public class BoundedExecutor { private final Executor exec; private final Semaphore semaphore; public BoundedExecutor(Executor exec, int bound) { this.exec = exec; this.semaphore = new Semaphore(bound); } public void submitTask(final Runnable

Java executors: how to be notified, without blocking, when a task completes?

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问题 Say I have a queue full of tasks which I need to submit to an executor service. I want them processed one at a time. The simplest way I can think of is to: Take a task from the queue Submit it to the executor Call .get on the returned Future and block until a result is available Take another task from the queue... However, I am trying to avoid blocking completely. If I have 10,000 such queues, which need their tasks processed one at a time, I\'ll run out of stack space because most of them

How to make ThreadPoolExecutor's submit() method block if it is saturated?

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问题 I want to create a ThreadPoolExecutor such that when it has reached its maximum size and the queue is full, the submit() method blocks when trying to add new tasks. Do I need to implement a custom RejectedExecutionHandler for that or is there an existing way to do this using a standard Java library? 回答1: One of the possible solutions I've just found: public class BoundedExecutor { private final Executor exec; private final Semaphore semaphore; public BoundedExecutor(Executor exec, int bound)