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How Much Do You Know about Distributed Coordination Service Zookeeper?

How Much Do You Know about Distributed Coordination Service Zookeeper?

2 weeks ago 1 88

Zookeeper profile

Since we learned about a distributed framework (dubbo), which involved zookeeper, let’s start with a brief introduction to zookeeper.Zookeeper is a distributed coordination service that manages a large number of hosts.

1. Distributed applications

Distributed applications can perform specific tasks by coordinating them between them, and a fast and effective way of running networks across multiple systems at a given time (and at the same time)
Distributed applications have two parts: the server and the client application.As shown in the figure below:

Activiti analyses

4 weeks ago 1 172

The Activiti framework is one of the workflow frameworks that have developed rapidly in recent years with its open source features.Another workflow framework, JBPM5, is currently a very popular workflow framework.While these two frameworks are two different companies, the two frameworks have a lot to do with it.Tom Baeyens, the director of the Activiti workflow framework, has previously worked for jBoss, currently the publisher of JBPM5, as the chief architect of the previous JBPM4 workflow engine.But it was speculated that Tom Baeyens left jBoss to work for Alfresco because of internal contradictions within jBoss and a serious disagreement over the future version of the workflow engine.However, for months, Tom Baeyens has launched Activiti, an open-source workflow system based on the JBPM4 workflow engine.

(中文) RPC框架技术初窥

1 month ago 1 139

(中文)

RPC是什么

RPC(Remote Procedure Call Protocol)——远程过程调用协议,它是一种通过网络从远程计算机程序上请求服务,而不需要了解底层网络技术的协议。
RPC采用客户机/服务器模式。请求程序就是一个客户机,而服务提供程序就是一个服务器。首先,客户机调用进程发送一个有进程参数的调用信息到服务进程,然后等待应答信息。在服务器端,进程保持睡眠状态直到调用信息到达为止。当一个调用信息到达,服务器获得进程参数,计算结果,发送答复信息,然后等待下一个调用信息,最后,客户端调用进程接收答复信息,获得进程结果,然后调用执行继续进行。
以上是百度百科对RPC的解释。
一个通俗的描述是:客户端在不知道调用细节的情况下,调用存在于远程计算机上的某个对象,就像调用本地应用程序中的对象一样。

(中文) 深入解析jquery实现原理第一章

1 month ago 1 136

JQuery is a very good JavaScript library, which greatly enhances the development experience of the front end js, so I recently looked at the source code of JQuery and wanted to share some of my understanding with you.

How to Improve APP Retention Rate?

1 month ago 1 228

The sole purpose of business is to create and retain customers

Our APP marketers are always better at getting more and more people to use our products and become our users. But how do you keep them when you have them? It may not be hard for a new app to attract hundreds of millions of users. But it’s never easy to keep these users and increase the number of users to 100 million.
Although users retention needs us to spend a long time to complete the work, we can still take some measures to improve it in the short term and can improve user activity, such as some marketing activities or according to the user’s usage of history to their push precise related news. This is a good way to interact with the users to let them participate, users can be obtained from these activities and news to get more valuable things. Therefore, the app retention rate will be increased.

ORA 4031 error depth parsing

1 month ago 1 245

To fully understand the cause of the 4301 error is to understand the execution of the SQL statement and the structure of the Oracle Shared memory.


The communication process diagram between the client and Oracle

4 Effective Strategies to Improve the Engagement of APP Users

1 month ago 1 392

The definition of user engagement varies from product to product

For example, for a bookkeeping app, an effective user should be logged in every day to add his new income or spending. For an operator’s app, an effective user may be logging in once a month, charging a fee, or ordering additional traffic packets. Therefore, user engagement has no uniform quantifiable definition standard, but it is possible to form the standard of vertical industry. For Banks, for example, start times the average of 1.7 times the user is a reasonable value (the value come from Cobub’s long-term observations, Cobub is a domestic open source mobile application of statistical analysis tools).
Engagement is not like page views (PV), visitors (UV), users pay or conversion rate these indicators as easy to measure, not a data statistical analysis tools to directly reflect product user engagement. However, ignoring user engagement is very dangerous.

The Construction and Deployment of ELK Real Time Log Analysis Platform

1 month ago 1 711

1. The Initial Contact with ELK

1.1 Why ELK?

Logs mainly include system logs, application logs and security logs. The system operation and development personnel can log to understand the hardware and software information of the server, check the errors in the configuration process and the causes of the errors. The log can understand the server’s load, performance security, and take timely corrective actions to correct errors. In general, logs are stored separately on different devices. If you manage dozens or hundreds of servers, you’re still using the traditional method of logging each machine in turn. It feels cumbersome and inefficient. It is imperative that we use centralized logging management, such as open source syslog, to collect and summarize log collection on all servers. Centralized management after logging, log statistics and retrieval has become a more troublesome thing, normally we use grep, awk and wc Linux commands can realize retrieval and statistics, but to demand a higher query, sorting and statistics requirements and the huge machine quantity still use this way to avoid a bit overwhelmed.

Selection and Use of the Hadoop Yarn Scheduler

2 months ago 1 1720

1

1. the introduction

Yarn has the role of resource management and task scheduling in the Hadoop ecosystem. A simple understanding of the architecture of the Yarn is given before discussing its constructors.

The banking industry predicts and prevents the churn of users by big data

2 months ago 2 601

“50% of users worldwide have been replaced or are preparing to replace the banks they use, and in the US and Canada, the percentage of consumers changing their banks is on the rise.”  ——Global Consumer Banking Survey 2012, Ernst & Young.