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  MySQL Index Merge Optimization Practices

In production environment databases, it is often seen that some SQL where conditions include: equal condition on a normal index + primary key range query + order by limit Although using a normal index would be more efficient, the system chooses to use index merge instead in some cases. This article explores such index merge situations. Index Merge Official Introduction   The Index Merge access method retrieves rows with multiple range scans and merges their results into one. Generall...

   INDEX MERGE,MYSQL,PRIMARY INDEX,SECONDARY INDEX     2024-09-10 04:52:26

  Why does Symbian collapse?

On 24th January, Nokia announces a disappointing news that they would give up Symbian. The 808 PureView released last year will be its last Symbian model.  Symbian was born in 1998, it was supported by the then three mobile giants : Sony Ericson, Motorola and Nokia after its birth, later Samsung and LG also joined the Symbian camp. In 2000, the first Symbian model in the world Ericoson R380 was released, in 20006, there were over 100 million Symbian handphones on the market. But in 2007, t...

   Nokia, Symbian, Collapse, Analysis     2013-01-28 03:06:09

  Responsive Web Design

With the popularity of 3G, more and more people are surfing the Internet using mobile phones. Mobile devices are becoming common devices for accessing internet. So web design faces a big challenge which is how to display the same webpage on different devices with different screen  resolutions.Screen resolution of mobile device are usually not very large, the width is below 600px, while PC usually has a resolution over 1000px. It is not an easy task to display the same content with satisfyin...

   CSS,Web design,Layout,Response web design     2012-05-03 06:59:40

  Understanding PGO in GoLang 1.20

Background The Go 1.20 version was officially released in February 2023, it introduced the PGO(Profile Guided Optimization) mechanism. The basic principle of PGO can be divided into the following two steps: First, profiling is performed on the program to collect data about the program's runtime and generate a profiling file. When compiling the program, enable the PGO option, and the compiler will optimize the program's performance based on the content in the .pgo file. When compiling a program...

   GO 1.20,PGO,GOLANG     2023-02-28 04:27:46

  All I Know About Certificates -- Clients

 Finally, in last article we’ve covered the responsibilities of CAs, showing that being a CA isn’t simple and has high management costs, explaining why issuing certificates costs money! This article we will cover the client in this chain. Verifying Certificates as a Client For clients, verifying certificates isn’t simple either. Articles introducing TLS handshakes often mention "the server sends back a certificate, and the client verifies it," but in reality, as ...

   CLIENTS,WEBSITES,SSL CERTIFICATE,CERTIFICATE AUTHORITY,CA     2024-07-26 22:24:30

  REST和gRPC对比全知道

长期以来，REST是构建API的唯一“标准”。它取代了混乱的“太多XML”的SOAP。但是近年来，出现了新的替代品。2015 年，Facebook 向公众发布了GraphQL，而 2016 年，Google 推出了gRPC。本文将重点介绍 gRPC，并与仍广泛使用的 REST 进行比较。 概述 以下表格将为您提供讨论点的概述，并显示 REST 和 gRPC 的优劣之处。 主题 REST gRPC 标准化 没有标准 定义明确 范式 基于资源...

   COMPARISON,GRPC,REST     2023-04-29 06:44:09

  Hello, Kernel!

When we learn module programming, the first small program must be hello, kernel!. For a novice, how do we avoid some mistakes and how to fix the bugs we have when writing the first module program? Is there any example we can refer to? Here is one example. 1. Write the hello.c 01 #include <linux/init.h> 02 #include <linux/module.h> 03 #include <linux/kernel.h> 04 //Compulsory 05 //Module lincese declaration 06 MODULE_LICENSE("GPL"); ...

   module,kernel,Linux     2013-05-03 03:33:52

  Is Java Set ordered or not?

“Is Java Set ordered or not? ” is the most popular question asked when you interview for a Java Developer position. Many fail to answer it, and I have to admit I was one of the many. I have known the answer is “Yes and No” for a long time. No. HashSet is not ordered. Yes.TreeSet is ordered. If the interviewer continues with some follow up questions, I’m not confident that I know the answer then. Why is TreeSet ordered? Are there any other ordered S...

   ORDER,SORTEDSET,HASHSET,JAVA     2021-02-11 06:55:00

  A simple tutorial on GoLang connecting to Clickhouse

Go, also known as Golang, is a statically-typed, concurrent programming language created by Google. ClickHouse is a high-performance, column-oriented database management system that can be used for real-time data analysis. This tutorial will provide a deep dive into how to connect to ClickHouse from a Go program, including how to perform common database operations such as SELECT and INSERT statements. Before proceeding, it is assumed that you already have Go and ClickHouse installed on your mach...

   GOLANG,CLICKHOUSE,TUTORIAL     2023-02-11 07:05:36

  As A Hottest Job Ever, What Should You Know As A Front End Web Developer?

The front end web developers are the openers for the visitors to visit the web page. It is also known as the client-side development, works predominantly with HTML, CSS, and Javascript. The tools and techniques are the important players of the front end web development. The developer must be aware of the updation of web technologies.The scope is evergreen with this technology as every company or business needs a website to showcase their profile. There are many objectives must be measured while ...

   FRONT END DEVELOPER,WEB DEVELOPERS,SOFTWARE DEVELOPERS,TOP SOFTWARE COMPANIES     2019-08-12 05:36:28

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