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Hello! I'm kicking off another article series about the internals of PostgreSQL. This one will focus on query planning and execution mechanics. This series will cover: Query execution stages (this article) Statistics Sequential scan Index scan Nested-loop join Hash join Merge join This article borrows from our course QPT Query Optimization (available in English soon), but focuses mostly on the int

This article compares the performance of several different web servers for a Laravel-based application. What follows is a lot of graphs, configuration settings, and my personal conclusions which do not pretend to represent universal truth in any way. I myself have been working with NGINX Unit (+ Lumen) for a while, but I still see PHP-FPM being used in new projects quite often. When I suggest swit

Machine readable API descriptions (OpenAPI, WSDL, WADL) are typically hard-coded into API policy at the policy deployment stage, but human readable versions in HTML can be generated automatically during the request from machine readable versions or also hard-coded into API policy when automatic conversion is not practical. For example, there are few free XSL templates which can be used to automati

Kernel Queue: The Complete Guide On The Most Essential Technology For High-Performance I/O When talking about high-performance software we probably think of server software (such as nginx) which processes millions requests from thousands clients in parallel. Surely, what makes server software work so fast is high-end CPU running with huge amount of memory and a very fast network link. But even the

Disclosure of three 0-day iOS vulnerabilities and critique of Apple Security Bounty program I want to share my frustrating experience participating in Apple Security Bounty program. I've reported four 0-day vulnerabilities this year between March 10 and May 4, as of now three of them are still present in the latest iOS version (15.0) and one was fixed in 14.7, but Apple decided to cover it up and

These passwords can be recovered from firmware as well by bruteforce of hash in /etc/passwd file. Modern consumer-grade GPGPU with hashcat is capable to find pre-image for hash in a matter of hours. Debug port 9527 accepts same login/password as Web UI and it also provides some shell access and functions to control the device. Speaking of Web UI accounts, attacker may reset password or grab passwo

Vue, Storybook, TypeScript—starting a new project with the best practices in mind (originally published on Medium) I like writing React code. This might be an odd introduction to a story about Vue, but you need to understand my background to understand why I’m here discussing Vue. I like writing React code and I hate reading it. JSX is a neat idea for assembling the pieces together fast, Material-

Python consumes a lot of memory or how to reduce the size of objects? A memory problem may arise when a large number of objects are active in RAM during the execution of a program, especially if there are restrictions on the total amount of available memory. Below is an overview of some methods of reducing the size of objects, which can significantly reduce the amount of RAM needed for programs in

I’m going to hazard 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. But, if my friends are any indication, very few people know that the service is community-driven and is supported by a group of enthusiasts gathering and sending data. Even fewer people know that anyone can

StarCraft: Brood War. This game means so much to me! And to many of you, I guess. So much, that I wonder if I should even give a link to its page on Wikipedia or not. Once Halt sent me PM and offered to learn Rust. Like any ordinary people, we decided to start with hello world writing a dynamic library for Windows that could be loaded into StarCraft's address space and manage units. The following

Не так давно при разработке фильтра файловых систем возникла проблема, которая приводила к подвисанию всей системы. Казалось бы, фильтр выполнял очень простые действия и сам был очень примитивным. Чтобы выяснить причину, пришлось спуститься до отладки и реверс-инжиниринга драйвера NTFS. Анализ выявил очень интересный эффект. Если скомпилировать и выполнить очень простую программу, изображенную на