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  What is cache penetration, cache breakdown and cache avalanche?

When designing and developing highly available system, cache is an very important consideration. It is useful to cache some frequently accessed data so that they can be accessed quickly and also cache can protect the downstream system like DB from being hit too often.  To provide better cache design in large systems, some problems may need to be considered first. In this post, we will talk about some frequently discussed cache problems and mitigation plans. Cache penetration Cache penetrati...

   SYSTEM DESIGN,CACHE PENETRATION,CACHE BREAKDOWN,CACHE AVALANCHE     2020-04-10 08:43:00

  Difference between localhost and 127.0.0.1

Lots of people would think what the address 127.0.0.1 is when first seeing this address. In fact, 127.0.0.1 is a loopback address which refers to the local machine. It is generally used for local testing. When typing ping 127.0.0.1 on local command console, it will send network packets to local IP/TCP layer to test whether IP/TCP works properly or not.  To those who are used to use localhost, it is actually mapped to 127.0.0.1 by default. There are hosts files in the system which store this...

   LINUX,NETWORK,LOCALHOST,127.0.0.1,LOCALHOST VS 127.0.0.1     2018-09-29 22:11:12

  Set up Superset on ubuntu 16.04 LTS

Apache Superset (incubating) is a modern, enterprise-ready business intelligence web application. Compared with business-focused BI tool like Tableau, superset is more technology-navy. It supports more types of visualization and able to work in distributed manner to boost the query performance. Most importantly, it is free of charge! An example dashboard: Let’s go and set it up. Create a virtualenv Assume Anaconda is installed for python management. # create a virtualenv with python 3.6 co...

   TUTORIAL,UBUNTU,SUPERSET     2019-10-19 21:34:55

  8 Step Guide to Rewrite Articles

Crafting an eye-catching article may be god-gifted talent, for many people. But anyone can learn the skill of article rewriting. You can find articles all around, newspapers, websites, and magazine even at the back of different products. These articles will give a basic understanding of what readers look into articles and what they expect. It will help you to craft an appealing article according to readers demand. For beginners, below you will find a list of four types of articles. Description...

   ARTICLE WRITE,TOOL     2019-05-15 07:58:52

  FTP Must Die

The File Transfer Protocol (FTP) is specified in RFC 959, published in October 1985. The attempt in this specification is to satisfy the diverse needs of users of maxi-hosts, mini-hosts, personal workstations, and TACs, with a simple, and easily implemented protocol design.That's from the introduction. Does anyone here know what a TAC is? I don't. I had to look it up, since the acronym wasn't even expanded in the RFC. It took three tries in Google, and I finally found it in some obscur...

   FTP,Future,Death,Trend,Protocol     2012-02-06 08:13:36

  C Preprocessor Hell

Lisp programmers should stop reading right now because they'll likely suffer severe injury of the jaw muscles as they laugh themselves silly at how hard it is to do some things in C. The C language has a pre-processor (typically called cpp) that is both infuriating and powerful. How powerful is usually best described as 'just too little' and it has happened more than once that I found myself almost - but not quite - able to do what I wanted to do. The frustration can run very deep at ti...

   C,Preprocessor,Lisp,Hell     2012-01-19 10:22:31

  Deep Dive into Spin Locks in Golang

In concurrent programming, a Mutex is a commonly used synchronization mechanism to protect critical resources and prevent data races. However, in certain specific scenarios, especially when the lock-holding time is short and the number of threads is limited, a more lightweight lock known as a Spin Lock can provide higher performance. What is a Spin Lock A Spin Lock is a form of busy-wait lock. When a thread attempts to acquire a lock held by another thread, it continuously checks the lock's stat...

   SPINLOCK,MUTEX,GOLANG     2024-01-10 05:53:28

  Which web front-end framework to choose?

When doing web design, we often need to choose which front-end framework to use in order to provide great user experience and simplify the development. Also, compatibility problem can be solved by using front-end frameworks. Here is a list of front-end frameworks. Which one are you using? Which one do you prefer?1. Apache FlexApache Flex, is a software development kit for the development and deployment of cross-platform rich Internet applications based on the Adobe Flash platform. Initially deve...

   Web design,Front-end,Framework     2012-07-30 13:57:26

  sorting in C++: 3 times faster than C.

If you don't know C++ well, you might be surprised how fast C++ can be sometimes. This is especially true when code involved is small, because then inlining - which is what C++ is very good at - and templating, which makes excessive inlining possible in the first place - has the most effect. The following code compares C and C++ sorting:  #include <iostream>#include <algorithm>#include <vector>#include "stop_watch.inl" // see https://...

   C++,Sorting,C,faster,efficiency     2012-03-17 12:59:45

  Guide to Implement an SSH Client Using Golang

SSH, short for Secure Shell, is a network protocol used for securely remote logging into other computers on a network. I believe most backend developers are familiar with SSH. Common shell tools used for logging into servers, such as Xshell, SecureCRT, and iTerm2, are all based on the SSH protocol. In Golang, the crypto/ssh package provides functionality for implementing an SSH client. In this article, we will explain in detail how to implement an SSH client using Golang. Creating SSH Client Con...

   SSH CLIENT,GUIDE,SSH,GOLANG     2023-11-11 09:19:29