Programmer Group

Adding fields to a table of ten million or more levels in MySQL has always been a headache. In this case, how to deal with it? This paper uses three common scenarios to illustrate the case. 1. Environmental preparation Database version: 5.7.25-28 (Percona branch) Server configuration: three centos 7 virtual machines with 2CPU 2G memory Database ...

Since C++11, it has provided many traversal tools. Some tools in the boost library have also entered the C + + standard library. Boost, as a "quasi" standard library, is also the knowledge and skills that C + + needs to master as much as possible. Now we use std::bind to realize the asynchrono ...

1. Background: Because wechat applets need to be developed in light weight, cross platform and short development time, many companies regard applets as the first APP for business presentation. The communication part of E-chat client core SDK has been adapted to wechat applet platform. Let's share the ideas and methods in the adaptation process. ...

Basic information of LAN transmission 1. What is Io? ⦁ definition ⦁ blocking IO ⦁ non blocking IO 2.IO multiplexing definition select specific usage 3. Realize the file transmission of multiplex LAN server.py client.py FileOperation.py matters needing attention Operation effect 1. What is ...

rsync introduction rsync is called remote synchronization in English. From the name of the software, it can be seen that rsync can make the data between the local and remote hosts copy the synchronous image and remote backup quickly. This function is similar to the scp command with ssh, but it is bet ...

1, rsync introductionrsync is called remote synchronization in English. From the name of the software, it can be seen that rsync can make the data between the local and remote hosts copy the synchronous image and remote backup quickly. This function is similar to the scp command with ssh, but it is bett ...

This chapter is about parallel computing, accounting for more than 60 pages. After reading it, we have to straighten out and digest this big lump of things. 1. Using Monte Carlo simulation to estimate pi. The logic is simple: put the needle in the unit square of the coordinate system, calculate the proportion of the needle falling in the 1 / 4 ...

what that? Zookeeper is frequently used in distributed development, but many frameworks encapsulate it. Beginners may not understand its working principle well. This article demonstrates the simple demo of using zookeeper to realize service registration and service discovery, hoping to achieve the effect of attracting valuable ideas; why need ...

Simple command line implementation based on STM32 Hi,long time no see. I looked at the atomic usmart and lwip official shell, and found that they all had one thing in common. After identifying the first command, I began to find the callback, and did not count the argc and argv. There are also many peo ...

Java 13 It has been officially released on September 17, 2019, Download Java 13 here Or here openJDK archived . Java 13 features. JEP 350: dynamic CDS Archive JEP 351: ZGC: uncommit unused memory JEP 353: re implement the old socket API JEP 354: switch expression (Preview) (developer ...