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Indexes in PostgreSQL — 6 (SP-GiST)

Reading time11 min
Views9.3K
We've already discussed PostgreSQL indexing engine, the interface of access methods, and three methods: hash index, B-tree, and GiST. In this article, we will describe SP-GiST.

SP-GiST


First, a few words about this name. The «GiST» part alludes to some similarity with the same-name access method. The similarity does exist: both are generalized search trees that provide a framework for building various access methods.

«SP» stands for space partitioning. The space here is often just what we are used to call a space, for example, a two-dimensional plane. But we will see that any search space is meant, that is, actually any value domain.

SP-GiST is suitable for structures where the space can be recursively split into non-intersecting areas. This class comprises quadtrees, k-dimensional trees (k-D trees), and radix trees.
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Flightradar24 — how does it work? Part 2, ADS-B protocol

Reading time9 min
Views8K
I’m going to have a guess and say that everyone whose friends or family have ever flown on a plane, have used Flightradar24 — a free and convenient service for tracking flights in real time.

image

In the first part the basic ideas of operation were described. Now let's go further and figure out, what data is exactly transmitting and receiving between the aircraft and a ground station. We'll also decode this data using Python.
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Dozen tricks with Linux shell which could save your time

Reading time10 min
Views9.1K


  • First of all, you can read this article in russian here.

One evening, I was reading Mastering regular expressions by Jeffrey Friedl , I realized that even if you have all the documentation and a lot of experience, there could be a lot of tricks developed by different people and imprisoned for themselves. All people are different. And techniques that are obvious for certain people may not be obvious to others and look like some kind of weird magic to third person. By the way, I already described several such moments here (in russian) .

For the administrator or the user the command line is not only a tool that can do everything, but also a highly customized tool that could be develops forever. Recently there was a translated article about some useful tricks in CLI. But I feel that the translator do not have enough experience with CLI and didn't follow the tricks described, so many important things could be missed or misunderstood.

Under the cut — a dozen tricks in Linux shell from my personal experience.
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Details

Reading time6 min
Views1K
How often do you get to 404 pages? Usually, they are not styled and stay default. Recently I’ve found test.do.am which interactive character attracts attention and livens up the error page.

Probably, there was just a cat picture, then they thought up eyes movement and developer implemented the idea.imageNow user visits the page and checks out the effect. It’s cool and pleasant small feature, it catches, then user discusses it with colleagues or friends and even repeats the feature. It could be this easy, if not:

Pentesting Azure  — Thoughts on Security in Cloud Computing

Reading time3 min
Views1.6K
A few months ago I worked with a customer on how a team should evaluate the security of their Azure implementation. I had never done a pentest(extensive security testing)on an Azure application before, so these ideas were just the thoughts off of the top of my head at that time based on my experience in security.

Matt Burrough’s book, Pentesting Azure Applications, goes even deeper and it is a must-read for security experts focused in Cloud Computing, I’m reading it right now.

Below I share with you these pre-book thoughts, and will compare them in a future article with the ones I will learn — or confirm — after reading Matt's book.

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Learning to Computer: How to Gain a New Skill

Reading time5 min
Views1.1K

Most people assume that I studied computer science in university and that I’ve been coding since I was young. They’re usually surprised when I tell them that in fact I studied Marketing and Spanish and that although my brother taught me how to build a very basic web page in the early 2000s, I didn’t really start to learn to program until I was an adult with a job.


The truth of the matter is that my story isn’t unique. It’s simply not true that you have to be a whiz kid who’s been coding since they were 6 years old in order if you want to be able to program as an adult. There are tons of examples of people who also don’t have a technical background who either became full time programmers or just learned a new skill they enjoy using.


In this post, I’ll give you some advice that has served me well on my journey. My path is by no means the only path and depending on the situation you’re in might not be practical or right for you, but it is certainly a path, and I hope it helps you on your path to learning to computer.

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The Processing of Unrecoverable Errors in Swift

Reading time6 min
Views3.8K

Preface


This article is an example of how we can do research into Swift Standard Library functions behavior building our knowledge not only on the Library documentation but also on its source code.


Unrecoverable Errors


All events which programmers call "errors" can be separated into two types.


  • Events caused by external factors such as a network connection failure.
  • Events caused by a programmer's mistake such as reaching a switch operator case which should be unreachable.
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Announcing TypeScript 3.3

Reading time5 min
Views1.1K

If you’re unfamiliar with TypeScript, it’s a language that brings static type-checking to JavaScript so that you can catch issues before you even run your code – or before you even save your file. It also includes the latest JavaScript features from the ECMAScript standard on older browsers and runtimes by compiling those features into a form that they understand. But beyond type-checking and compiling your code, TypeScript also provides tooling in your favorite editor so that you can jump to the definition of any variable, find who’s using a given function, and automate refactorings and fixes to common problems.

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Announcing F# 4.6 Preview

Reading time10 min
Views1.6K

We’re excited to announce that Visual Studio 2019 will ship a new version of F# when it releases: F# 4.6!


F# 4.6 is a smaller update to the F# language, making it a “true” point-release. As with previous versions of F#, F# 4.6 was developed entirely via an open RFC (requests for comments) process. The F# community has offered very detailed feedback in discussions for this version of the language. You can view all RFCs that correspond with this release here:



This post will detail the feature set and how to get started.

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Videogame monsters: how to sow fear

Reading time4 min
Views3.3K

In video games, enemies are one of the key figures, without which a game might lose its meaning, and when it’s not only enemies, but terrifying monsters, they often create the chilling atmosphere intended by the developers. It’s impossible to imagine Silent Hill without the Pyramid Head, or Outlast without Chris Walker, and so on, you get the idea. Monsters are a cumulative image of a video game enemy, and it’s not necessarily an ugly demon or a giant spider: even an angry neighbor, like in Hello Neighbor, is a monster despite his human appearance.

This is where the reader probably asks:


what’s the point of this article?
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Lifetime Profile Update in Visual Studio 2019 Preview 2

Reading time5 min
Views1.4K

The C++ Core Guidelines’ Lifetime Profile, which is part of the C++ Core Guidelines, aims to detect lifetime problems, like dangling pointers and references, in C++ code. It uses the type information already present in the source along with some simple contracts between functions to detect defects at compile time with minimal annotation.



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