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  How to optimize MySQL insert statement

For a big data system, one problem is the data access efficiency, one more problem is that the data insertion is very slow. We had a service system, the data loading process would take 4-5 hours. This time consuming operation is risky since if the program is interrupted during the loading process, it might be rerun, this will be troublesome. So it's necessary to improve the insertion efficiency for big data systems. Here we provide two optimization suggestions. 1. Combine multiple insert stateme...

   MySQL,insert,optimization     2012-10-24 22:03:13

  The 7 stages of refactoring

You have wanted to fix that module for ages. Just one look at it and you cringe. The documentation, the weird naming of functions, classes that are just plain weird. The module hobbeles along, but it is just plain dirty. The real programmer in you cringe, and when there finally is some time to refactor the module, you jump at it. Step 1 - Desperation  So you start to have a real good look at what you need to. Fix a class here, rename a few functions there, tear out a few function...

   Refactoring,Software,Desperation     2011-08-16 08:35:57

  Avoiding and exploiting JavaScript's warts

One's sentiment toward JavaScript flips between elegance and disgust without transiting intermediate states. The key to seeing JavaScript as elegant is understanding its warts, and knowing how to avoid, work around or even exploit them. I adopted this avoid/fix/exploit approach after reading Doug Crockford's JavaScript: The Good Parts: Doug has a slightly different and more elaborate take on the bad parts and awful parts, so I'm sharing my perspective on the four issues that ha...

   JavaScript,warts,Exploit,with,variable,this     2012-02-15 05:51:21

  Load and execute JavaScript

When we load and execute JavaScript in a webpage, there are many points we need to care about because of its design and feature. There are two features about JavaScript execution in a browser: 1). The JavaScript codes will be executed immediately once loaded;2). When JavaScript codes are being executed, they will block the following contents (including page rendering and other resources downloading). So if there are multiple js files to be loaded, these codes will be executed sequentially. Since...

   JavaScript,async,defer,load,execute     2013-06-07 04:53:46

  Using Angular 2 with Asp.Net MVC/Asp.Net Core

Asp.net development professionals bring this post to explain the use of Angular 2 with Asp.net MVC/ Core. You will read the overview of Angular 2 and Asp.net Core at first in this post. Read the article to find how experts use Angular 2 with MVC / Core. Angular 2 Overview Angular 2 is the upcoming version of MV framework used for creating high level applications in browser. It contains everything needed to create a complex mobile or web apps from a variety of templates. Angular team recently re...

   ASP.NET DEVELOPMENT,ANGULAR 2, ASP.NET MVC     2016-10-29 05:15:06

  Recover deleted file in Linux EXT3 file system

Environment : CentOS 5.3 x86_64, /dev/sdb1 is the data segment /data0. EXT3 file system. Problem : /data0/tcsql/cankao/phpcws-1.5.0/httpcws.cpp is deleted mistakenly and httpcws.cpp is not backed up. It will take much time to rewrite this program again. So we must recover it back. debugfs is feasible in EXT2 file system, but in EXT3 file system, it's not very useful. There is one open source software called ext3grep which can help us recover deleted file in EXT3 file system. The recovery steps a...

   Linux,EXT3,File recovery     2013-08-16 07:06:45

  20 bit operations programmers should know

While talking about bit operation, programmers usually think about its efficiency. In embedded programming and system core optimization, appropriate use of bit operations is always a fascinating. When finding a job, it will help you a lot if you use bit operations when writing codes. Mastering simple bit arithmetic skills is necessary. 1. Get maximum int value int getMaxInt(){           return (1 << 31) - 1;//...

   Bit operation, Tips     2012-12-19 12:53:33

  Write Your Own R Packages

Introduction A set of user-defined functions (UDF) or utility functions are helpful to simplify our code and avoid repeating the same typing for daily analysis work. Previously, I saved all my R functions to a single R file. Whenever I want to use them, I can simply source the R file to import all functions. This is a simple but not perfect approach, especially when I want to check the documentation of certain functions. It was quite annoying that you can’t just type ?func&n...

   DATA SCIENCE,R PROGRAMMING,DATA ENGINEERING     2019-10-19 07:20:52

  Overlap Detection

How does one detect when two strings overlap? In the case below, the four-letter suffix of string 1 matches the four-letter prefix of string 2. 1: "Fire at Will" 2: "William Riker is number one" Sometimes there are several matches; finding the longest is not always straight forward. 1: "Have some CoCo and CoCo" 2: "CoCo and CoCo is here." 2: "CoCo and CoCo is here." 2: "CoCo and CoCo is here." The naïve solution is to take...

   String overlap,detection,python,implementation     2012-03-05 05:05:36

  Output a file with HTTP range header in PHP

When downloading a large file, we may encounter some network issues which causes download termination and only part of the file is downloaded. When the network connection resumes next time, we may need to redownload the file again from the beginning. In order to save bandwidth, http provides a Range parameter in its header which can control the file transfer flow. With the range parameter in the header, we can resume the download from where we stop. Here is a piece of PHP code snippet which uses...

   PHP, range,http, file transfer     2013-01-09 05:55:05