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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

  The Ultimate Guide to Implement Function Overloading in Python

Introduction When it comes to function overloading, those who have learned Java should be familiar with it. One of the most common uses is logging, where different overloaded functions are called for different parameters. So, how can we implement function overloading in Python? Concept of Overloading Function overloading allows multiple functions with the same name to exist within the same scope, but with different parameter lists. Although many programming languages (like Java and C++) support ...

   GUIDE,JAVA,OVERLOADING,PYTHON     2024-11-14 22:29:17

  A couple of tips for beginning programmers

Whether it is football, quantum physics, a new foreign language or programming, the beginnings are problematic. What is more, no amount of advice can teach you as much as your own experience. Nevertheless, the following tips will help you avoid some mistakes, save your time and develop good programmer habits from the very beginning.Practise logical thinkingAlthough some may laugh at the stereotype of a programmer being a Maths genius, there is no use denying that learning Maths and Logics prepar...

   Programming,Tips,Beginner     2014-06-17 07:47:31

  Some frequently used ES6 code snippets

Below are a list of ES6 code snippets which are used frequently. Hope that it will be helpful. 1. Shuffle array elements let arr = [67, true, false, '55'] arr = arr.sort(() => 0.5 - Math.random()) console.log(arr) // [ '55', 67, false, true ] 2. Remove characters which are not numbers const str = 'xieyezi 23213 is 95994 so hansome 223333' const numbers = str.replace(/\D/g, '') console.log(numbers) // 2321395994223333 3. Reverse sequence or words const sentence = 'xieyezi js so handsome, lol.'...

   JAVASCRIPT,ES6,CODE SNIPPET,TIPS     2022-04-10 07:56:07

  Funny Linux commands

1. sl You will see a train moving from the right to left on the screen. Install : $ sudo apt-get install sl Run : $ sl It has options like -aiFe: -a An accident seems to happen. You'll feel pity for people who cry for help.-l shows little one.-F It flies.-e Allow interrupt by Ctrl+C. We can also make fun of other people by setting an alias like below: $alias ls=sl When the user types ls, he will see the train instead of the file list. 2. fortune Output one statement, it can be a joke, or famous...

   Linux,funny command,figlet,sl     2013-06-08 21:30:26

  Use progressive JPEG to improve user experience

JPEG image files can have two different save types : Baseline JPEG and Progressive JPEG. Both of them have the same extension name but with different display effect. Baseline JPEG This type of JPEG files are scanned from top to bottom consecutively, each line of the image data will be saved sequentially. When opening this kind of images, data will be displayed with the save order line by line until all the data are read. If the image size is very large or network speed is very slow, the image wi...

   USER EXPERIENCE,PROGRESSIVE JPEG,BASELINE JPEG     2013-07-25 08:11:50

  Microsoft Edge extension manifest v2 migration to v3

In June 2023, Microsoft Edge would not allow Edge extensions with manifest version before v3 to be listed on Microsoft web stores as v3 extensions add more security privacy related restrictions on some of the functions. Hence all extensions with manifest v2 must migrate to v3. In this post, we would show how we did the migration for one of our extensions and the changes made. There is a checklist provided by Microsoft Edge team on what needs to be updated so that the extension can stil...

   MICROSOFT EDGE,EXTENSION,MANIFEST V3     2022-10-01 02:54:47

  9 useful jQuery code snippets

jQuery is one of the most popular JS library among front end developers because of its functionality and usability. Here we share with you some useful jQuery code snippets which can be used in our daily front end development. 1. Smoothly return to page top $(document).ready(function() { $("a.topLink").click(function() { $("html, body").animate({ scrollTop: $($(this).attr("href")).offset().top + "px" }, { duration: 500, easing: "swing" ...

   jQuery,Code snippet     2013-07-13 00:11:10

  Chrome extension manifest v2 migration to v3

In 2023, Google would not allow Chrome extensions with manifest version before v3 to be listed on Chrome web stores as v3 extensions add more security privacy related restrictions on some of the functions. Hence all extensions with manifest v2 must migrate to v3. In this post, we would show how we did the migration for one of our extensions and the changes made. There is a checklist provided by Chrome team on what needs to be updated so that the extension can still work in v3. It can be checked ...

   CHROME EXTENSION,MANIFEST V3,MIGRATION     2022-09-24 10:44:54

  Linux Clock : CST,UTC and NTP setup

1. There is an option when you set up clock on installing Linux: system clock users UTC, so what does UTC mean? It's Universal Time Coordinated(UTC), there are two different times in GPS system: one is UTC , the other one is LT(Local Time). The difference between these two is just the timezone difference, UTC is the time in timezone 0. If the local time in Beijing is 8 o'clock in the morning, then UTC time is 0 o'clock, which is a 8 hour difference. 2. In Linux, when we use date to check the tim...

   Linux,Clock,UTC     2013-03-21 12:19:30

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