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  Inline IF and CASE statements in MySQL

There are times where running IF statements inside a query can be useful. MySQL provides a simple way to do this through the use of IF and CASE statements. The IF statement takes three arguments; the conditional, the true value and the false value. False and true values may be static values or column values. For example: SELECT IF(score > 100, 100, score) AS score FROM exam_results this will return the value in the score column limited to a maximum value of 100. IF statements can a...

   MySQK,IF,Condition,CASE,SQL     2012-04-22 10:37:01

  File System vs Core Data: the image cache test

Code for this project is on GitHub While doing a full re-write of Droplr's iOS app for the 2.0 launch, I couldn't find any good file/image caches out there had a particular feature I really wanted: extending item expiration whenever it's touched. I set out to write my own — which wasn't that much of a challenge — but somewhere along the process I had this crazy idea that perhaps (SQLite-backed) Core Data would be a much better tool for the job: No mismatch between cache index ...

   File system.Image cache,Multimedia     2012-02-01 08:52:02

  How to do pprof for gRPC service

gRPC is a RPC framework based on HTTP and is frequently used for communications among micro service inside the same organization network. However,  the service functions cannot be accessed via normal HTTP URL as it's not a WEB framework. In this case, how to do pprof on a gRPC service? The trick is starting a HTTP server asynchronously while starting the gRPC service. This HTTP server can be accessed to run prrof debug. go func(){ http.ListenAndServe(":10001", nil) }() Since it uses the de...

   GOLANG,PPROF,GRPC     2021-01-29 23:11:33

  5 good anti SOPA designs

The Stop Online Piracy Act (SOPA) is a United States bill to expand the ability of U.S. law enforcement to combat online copyright infringement and online trafficking in counterfeit goods. Its goal is to protect the intellectual-property market and corresponding industry, jobs and revenue. However since its proposal, many organizations protest against it as they believed it would threaten free speech and innovation, and enable law enforcement to block access to entire internet domains due t...

   SOPA,PIPA,design     2013-12-24 03:26:31

  How does GoLang know how many CPUs to use?

When running lscpu command on Linux, it will list the CPU info on the machine. Take one example where there is one CPU with 2 cores and each core has two threads which indicates there are 4 cores available. Now let's see how many cores GoLang program would identify. From output, NumCPU and GOMAXPROCS both output 4 which is expected. How does go runtime get this info, does it get it through similar command like lscpu or /proc/cpuinfo? Let's dig more in GoLang's source code. In runtim...

   GOLANG,CPU,NCPU     2020-12-29 23:22:15

  Becoming a Better Developer, Part 2: Know Your Core Competencies

If you're trying to grow your startup you've come to the right place. Get my 170-page ebook on how to grow a startup and join thousands of self-funded entrepreneurs by subscribing to my newsletter at right. For years business consultants have instructed businesses to “know your core competencies.” What this means is “know what you do well and stick to it.” For example: Harley Davidson makes great motorcycles. But they’re probably not so good at making per...

   Developer,Tips     2011-06-29 08:40:10

  Use Memory Analyzer Tool in Eclipse

When developing applications, we often encounter memory issues of an application. To analyze how much memory each class takes, we need to have some specific tools to assist us. One of them is Memory Analyzer Tool on Eclipse. The Eclipse Memory Analyzer is a fast and feature-rich Java heap analyzer that helps you find memory leaks and reduce memory consumption. To use the Memory Analyzer Tool, you first need to install it on Eclipse. You can go to Help -> Install New Software.... Paste  h...

   Memory analyzer tool, Eclipse,heap dump, HPROF     2014-10-28 07:22:35

  Build a Kubectl Plugin from Scratch

by author The command-line tool kubectl is indispensable when using Kubernetes. You need it to query related Pod and Service information both in developing or performing some maintenance operations, such as events, scale, rolling update, etc. However, when using kubectl, there are many inconveniences. Though Kubernetes is officially maintaining kubectl¹, and you can submit the problems, improvement, and even PR in its Github Issues, you still have to wait long before its release. The m...

   KUBENETES,KUBECTL,PLUGIN,GOLANG     2020-12-02 03:43:16

  A boolean value interview question

Someone asked a question on StackOverflow, he was asked an interview question. The question is : Given 3 boolean variables a, b, c, return true if at least 2 out of the 3 are true. He gave the solution as follows :boolean atLeastTwo(boolean a, boolean b, boolean c) {    if ((a && b) || (b && c) || (a && c)) {        return true;    } else {        ret...

   bool,return,expression,conditional     2012-04-30 08:49:32

  The magic of go:linkname

When writing Go program, there is frequent need on using time.Sleep() function to pause the logic for some time. And if jumping to the definition of this function, can see below definition: // Sleep pauses the current goroutine for at least the duration d. // A negative or zero duration causes Sleep to return immediately. func Sleep(d Duration) I's strange that there is no function body defined here. What happened? The actual definition of the function body is residing at runtime/time.go&nb...

   TRICKS,GO:LINKNAME,GOLANG     2022-04-10 08:39:00