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  Speed Hashing

A given hash uniquely represents a file, or any arbitrary collection of data. At least in theory. This is a 128-bit MD5 hash you're looking at above, so it can represent at most 2128 unique items, or 340 trillion trillion trillion. In reality the usable space is substantially less; you can start seeing significant collisions once you've filled half the space, but half of an impossibly large number is still impossibly large. Back in 2005, I wondered about the difference between a checksum and...

   Speed hashing,Security,MD5     2012-04-07 10:35:15

  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

  Stuff The Internet Says On Scalability For September 16, 2011

Between love and madness lies HighScalability:Google now 10x better: MapReduce sorts 1 petabyte of data using 8000 computers in 33 minutes; 1 Billion on Social Networks;Tumblr at 10 Billion Posts; Twitter at 100 Million Users; Testing at Google Scale: 1800 builds, 120 million test suites, 60 million tests run daily.From the Dash Memo on Google's Plan: Go is a very promising systems-programming language in the vein of C++. We fully hope and expect that Go become...

   Scalability,Go,Google,MapReduce,Muppet,M     2011-09-20 11:22:36

  Simple but Interesting Features of VS2010 and C# 4.0

IntroductionVS 2010 and C# 4.0 introduced so many new features. Here in this article, I try to cover some very simple, yet very useful features of both.1. Hiding the Selected Part of CodeMany a times, a situation arises when we want to hide a specified piece of code rather that hiding the entire region. This has become easier in VS 2010. Just select the part of the code that you want to hide and right click selectOutlining -> Hide Selection.Same way like a region code also gets collapsible an...

   VS2010,C#4.0,New feature,Walk through     2011-11-18 08:59:29

  â€œBuild something people want” is not enough

Most people take “Build something people want” to mean “Pick a problem to solve and solve it well.” This is not sufficient to build a world changing company.“Why now?” is the question entrepreneurs really need to answer. “Why now” encompasses two important and closely related concepts:Why have previous attempts at this idea failed?What enabling factors have emerged that enable you to succeed today?The world is full of smart people who have the same...

   User requirement,User friendly,Example,People needs     2011-11-16 08:18:45

  Python internals: adding a new statement to Python

This article is an attempt to better understand how the front-end of Python works. Just reading documentation and source code may be a bit boring, so I’m taking a hands-on approach here: I’m going to add an until statement to Python. All the coding for this article was done against the cutting-edge Py3k branch in the Python Mercurial repository mirror. The until statement Some languages, like Ruby, have an until statement, which is the complement to while (until num == 0 is equi...

   Python,New statement,Research,Addition     2012-03-12 07:32:24

  The First Bite on etcd Code

Etcd, one of the crucial components of Kubernetes. If APIServer is the heart, then etcd is the blood vessel that sends the end state of Kubernetes resources to various “organs”, providing high-speed, stable storage, and supporting APIServer’s high load performance. What if the etcd is not working properly? Just the condition as someone has a vascular disease. The deeper you know about them, the better diagnose you can make when issues occur. from unspl...

   SOURCE CODE,ETCD     2022-02-12 01:03:14

  Our Go Cache Library Choices

In Build a Go KV Cache from Scratch in 20 minutes, I walked you through what matters when writing a local cache, and eventually implemented one, whose performance was beaten badly by that of the popular go-cache on Github though. However, the bright side is that we can learn a lot from those excellent Github Go cache products, studying their features, applicable scenarios, and implementations, and extracting what we need. In this article, I will mainly analyze and compare the four...

   GOLANG,CACHE,GO-CACHE,BIGCACHE,GOURPCACHE     2022-04-16 07:48:11

  Functional Programming For Object Oriented Programmers

After recently remarking about how I finally "got" functional programming I was asked by one of my millions of twitter followers... ¬_¬ to write up an explanation of a small F# program spoken in terms that fellow O-O programmers would understand. Before I become too entrenched into the functional programming way of thinking, that is, and can't explain it anymore. As a former tutor this is one of the major problems with being able to teach something once you understand it. You've ...

   Functional programming,OOP,F#,Pattern     2011-11-25 13:49:16

  Python and PLC Communication

This article provides detailed steps on how to use Python to communicate with Schneider M221 and Siemens S7-1200 PLCs via Ethernet. Additionally, we offer a packaged Python PLC client library, enabling you to easily build your own SCADA control programs, such as Human-Machine Interfaces (HMI). The system overview is shown below: To check the project detail please refer to Python Physical PLC Communication Clients # Created: 2024/06/29 # Version: v0.1.3 # Copyright: Copyright (c) 2024 ...

       2024-06-30 02:21:17