SEARCH KEYWORD -- Problem solving


  How to check which Ohai plugin hangs in chef client run

Ohai plugins are very important components in chef client which aims to provide resource management automation on a server. The data discovered by Ohai plugins are describing the current state of the server and they will be used to maintain the server in a desired state. Each Ohai plugin discovers a specific pierce of information about the server such as cpu, memory, middleware etc. However, there are rare occasions(well I am a bit optimistic here) someone may find that the chef client...

   HOW TO,CHEF-CLIENT,OHAI,UPTIME,HANG     2017-12-24 22:09:59

  Data Scientists and Their Harder Skills than Big Data

The field of data science is often confused with that of big data. Data science is an aid to decision makers in a company with a logical approach.  Who is a Data Scientist?  A Data Scientist reviews a huge collection of data(that may extend to a couple of terabytes of disk space or thousands of excel sheets). This humongous chunk of data is not feasible for being handled, sorted and analyzed by a single person. Here we require the help of data science, and most recently, the field of A...

   BIG DATA     2017-12-13 04:22:55

  What have been Facebook’s greatest technical accomplishments?

To maintain a large website which gets billions of requests er day and keeps very fast response speed is not an easy task. Many big companies are trying best to improve user experience by adopting different techniques. There is a question on Quora which asks "What have been Facebook’s greatest technical accomplishments?". There is a person who worked in Facebook before provided an answer which helps us understanding how Facebook handles huge amount of traffic each day. Here is the answer f...

   Facebook, Design, Efficiency     2013-01-15 07:32:07

  Load html content properly in iframe

When loading content in an ifrasme, there are normally two ways: loading with src or creating iframe dynamically and set content dynamically. In this post, we will talk about how to properly load content in a dynamically created iframe element, especially on how to fix some issue we faced while in Firefox. To create an iframe dynamically, we would normally use JavaScript and with below piece of cod: let iframe = document.createElement("ifrasme"); iframe.innerHTML = "this is some text"; document...

   IFRAME,HTML,BLANK,FIREFOX,FIX     2021-04-10 02:17:27

  Click and Drag on xkcd

xkcd is a webcomic created by Randall Munroe. The comic's tagline describes it as "a webcomic of romance, sarcasm, math, and language." Also some webcomics about IT may frequently appear on it. For example, the following one-- People who know Unix will understand it easily. In fact, xkcd is a Geek culture, many comics inside this site can only understood by some specified group of people. The comic began in September 2005 when Munroe decided to scan doodles from hi...

   xkcd, 1110,Click and Drag     2012-11-05 11:23:19

  Eight C++ programming mistakes the compiler won’t catch

C++ is a complex language, full of subtle traps for the unwary. There is an almost infinite number of ways to screw things up. Fortunately, modern compilers are pretty good at detecting a large number of these cases and notifying the programmer via compile errors or warnings. Ultimately, any error that is compiler-detectable becomes a non-issue if properly handled, as it will be caught and fixed before the program leaves development. At worst, a compiler-detectable error results in los...

   C++,Compiler,Error detection     2012-04-08 09:55:20

  The Pitfall of WebSocket Disconnections Caused by Browser Power-Saving Mechanisms

Preface Recently, while using WebSocket (WS) connections, we encountered frequent disconnection issues, occurring hundreds of times per day for a single user. Although using the auto-reconnect feature of socket.io allowed us to quickly restore connections after disconnections, it did not guarantee that every reconnection would successfully receive WS messages. Therefore, we conducted several investigations and tests. Ultimately, we identified the root cause of the issue: the browser's power-savi...

   WEBSOCKET,JAVASCRIPT,POWER SAVING,TROUBLESHOOTING     2024-06-23 01:19:39

  GoLang Interview Questions

Below lists some frequently asked GoLang interview questions and their corresponding answers based on the author's experience. The list is updated frequently with new understandings. Stay tuned. What is the GMP model of GoLang? GoLang uses goroutine to achieve concurrency and it is famous for high concurrency support as the language defines its own goroutine dispatching and processing system which is well known as GMP model. How it works is that M is normally defined as the OS thread being spawn...

   MEMORY,CONCURRENCY,INTERVIEW QUESTION,GOLANG     2024-05-25 03:08:18

  Using JavaScript to operate clipboard

Browsers allow JavaScript to read and write data on clipboard. Generally script should not modify user's clipboard to avoid impacting user expectation, but there are cases where this can indeed bring convenience to users. For example, for some code snippet, user can copy it to clipboard with one click instead of select and copy manually. There are three options for clipboard operation provided in JavaScript/browser: document.execCommand() Asynchronous Clipboard API copy and paste events This p...

   JAVASCRIPT,CLIPBOARD,NAVIGATOR.CLIPBOARD     2021-01-23 23:23:34

  Use Java ThreadLocal with caution

According to Oracle documentation, ThreadLocal is a class provides thread-local variables. These variables differ from their normal counterparts in that each thread that accesses one (via its get or set method) has its own, independently initialized copy of the variable. ThreadLocal instances are typically private static fields in classes that wish to associate state with a thread. In short, ThreadLocal variables are variables belong to a thread, not a class or an instance of a class. One common...

   JAVA,MEMORY LEAK, THREADLOCAL     2015-11-03 07:31:57

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