Discussion on RocketMQ message consumption and rebalancing

In fact, the best way to learn is to communicate with each other. Recently, I also discussed some issues about RocketMQ message pulling and balancing with netizens. Let me write down my summary here. On the problem of message loop pull in push mode A previous article on rebalancing: Kafka rebalancing mechanism ", it is said that the Rocket ...

Posted by benbox on Mon, 04 Nov 2019 23:17:48 -0800

I. hbase -- basic principle and use

Hot issues of hbase data: The solution is to preprocess the rowkey of the hot data, add some prefixes, and distribute the hot data to multiple region s. Pre merger? Dynamic partition? At the beginning of the initial data, the data should be partitioned, stored in different region s, and load balanced. Example: for example, it is easy to divide ...

Posted by daniel_mintz on Mon, 04 Nov 2019 16:20:41 -0800

Installation configuration HBASE

I. preparation before experiment 1. Download hbase-1.4.9-bin.tar.gz installation package Official website https://mirrors.tuna.tsinghua.edu.cn/apache/hbase/stable/ ② Baidu online disk link: https://pan.baidu.com/s/1x6m30jqcWT_biXV8Z1belQ Extraction code: p95n 2. Connect the virtual machine and start the experim ...

Posted by sharmeen on Mon, 04 Nov 2019 11:32:30 -0800

App wechat payment

I. Basic Process of wechat payment Main interaction between merchant system and wechat payment system: Step 1: the user selects the goods in the merchant APP, submits the order and selects wechat payment. Step 2: the merchant receives the user payment form at the background and calls the unified order interface of wechat payment. See also ...

Posted by bfinucan on Mon, 04 Nov 2019 08:05:21 -0800

Big data (Introduction to Hadoop MapReduce code and programming model)

MapReduce programming model MapReduce divides the whole operation process into two stages: Map stage and Reduce stage The Map phase consists of a certain number of Map tasks Input data format analysis: InputFormat Input data processing: Mapper Data grouping: Partitioner The Reduce phase consists of a certain number of Reduce tasks Data remot ...

Posted by covert215 on Sun, 03 Nov 2019 15:15:53 -0800

I. zookeeper -- deployment and use

I. deploy zookeeper 1. Resource planning The server bigdata121/192.168.50.121,bigdata122/192.168.50.122,bigdata123/192.168.50.123 zookeeper version 3.4.10 System version centos7.2 2. Cluster deployment (1) install zk [root@bigdata121 modules]# cd /opt/modules/zookeeper-3.4.10 [root@bigdata121 zookeeper-3.4.10]# mkdir zkData [root@b ...

Posted by stndrdsnz on Sun, 03 Nov 2019 14:14:53 -0800

Java uploads pictures to the server

In the process of designing colorful websites or programs with rich business logic, there must be many related operations of pictures, especially the uploading of pictures. The paper office may need to backup and upload the paper documents, the website construction may need to upload the user's Avatar, picture description and so on, all of whic ...

Posted by l_evans on Sun, 03 Nov 2019 11:29:33 -0800

mapreduce [traffic statistics] sum - user defined data type

Demand: in the document, the total upstream traffic, total downstream traffic and total traffic consumed by each user 1363157985066 13726230503 00-FD-07-A4-72-B8:CMCC 120.196.100.82 i02.c.aliimg.com 24 27 2481 24681 200 1363157995052 13826544101 5C-0E-8B-C7-F1-E0:CMCC 120.197.40.4 4 0 264 0 200 1363157991076 13926435656 20-10-7A-28-CC- ...

Posted by alexguz79 on Sun, 03 Nov 2019 08:47:52 -0800

Marco - build a simple Apache service

1. View the service status of httpd: display the httpd unit, unable to find the service. [root@localhost ~]#systemctl status httpd Unit httpd.service could not be found. 2. Use yum to install httpd service. The following is the installation process: [root@localhost ~]#yum install httpd Loaded plugins: fastestmirror, langpacks Loading mirror sp ...

Posted by bolerophone on Sun, 03 Nov 2019 03:43:49 -0800

[Java compulsory course] four methods to obtain the Key Value Key in the Map through Value

1 Introduction We all know that Map is a container for storing Key Value pairs < Key, Value > and that the Key Value can be obtained quickly by using Map.get(key). However, sometimes we need to get the Value and find the Key. In this paper, four methods are introduced with an example. The Key Value is obtained by passing in the Value valu ...

Posted by piznac on Sun, 03 Nov 2019 02:42:22 -0800