Programmer Think

Author: duktig Blog: https://duktig.cn (first article) Excellent still work hard. May you enjoy what you give and enjoy what you get. See github knowledge base for more articles: https://github.com/duktig666/knowledge background After learning Hadoop, do you feel that writing a MapReduce program is very complex, and it requires a lot ...

Author: duktig Blog: https://duktig.cn (first article) Excellent still work hard. May you enjoy what you give and enjoy what you get. See github knowledge base for more articles: https://github.com/duktig666/knowledge background After learning Hadoop, do you feel that writing a MapReduce program is very complex, and it requires a lot ...

🌹 Write at the beginning Xiao Yuan began to update Hadoop series teaching articles to introduce you to big data from zero and look forward to your attention (according to the blog notes written by Hadoop 3. X in Silicon Valley) ❤️❤️ First article: Hadoop graphical overview of big data Second article: Hadoop template virtual machine con ...

Class loader subsystem 1.1 what is a class loading subsystem? The Class loader subsystem is responsible for loading Class files from the file system or network. The Class file has a specific file ID (magic number) at the beginning of the file. The Class loader subsystem (ClassLoader) is only responsible for loading the Class file. Whether it ...

1, Introduction to Azkaban 1.1 why workflow scheduling system is needed A complete data analysis system is usually composed of a large number of task units: Shell script program, Java program, MapReduce program, Hive script, etc;There are time sequence and before and after dependency among task units;In order to organize such a complex ex ...

1, Theoretical basis Spark operators can be divided into: Transformation Transformation/Conversion operator: this transformation does not trigger the submission of the job and completes the intermediate process of the job. Transformation Operations are deferred, that is, from a RDD Transform to generate another RDD The operation is not perfor ...

In the last section, you understood what ThreadLocal is, its basic usage, and the underlying principle of the get method. In this section, let's continue to study in depth: ThreadLocal set source code principleStrong reference, weak reference, soft reference and virtual reference in JVMApplication of weak reference in ThreadLocalAnalysis of ...

I recently built a distributed hadoop environment using four Centos virtual machines, which simply simulated the online hadoop real distributed cluster, which is mainly used for amateur learning big data related systems. One server serves as a NameNode, one as a Secondary NameNode, and the other two as DataNodes node servers, similar to the fo ...

1, Object oriented 1. Class and object details (1) Class composition structure Constructor, member variable, member method (function), local variable, code block, internal class (2) Constructor scala has two types of constructors: primary and secondaryThe main constructor follows the class name, such as class Student2(val name: String, ...

Eureka heartbeat mechanism: After the application starts, the nodes will report to Eureka   Server sends heartbeat. The default cycle is 30 seconds. If Eureka   The server does not receive the heartbeat of a node in multiple heartbeat cycles, Eureka   The server will remove the service node from the service registry (90 seconds ...