転置インデックスの圧縮技法
転置インデックスは、検索エンジンの実装において、中心的な役割を果たすデータ構造である。 転置インデックスのデータ構造とアルゴリズムは、クエリ処理アルゴリズムとともに、検索エンジンの性能に直結する。とくに大規模な検索エンジンにおいては、キャッシュ効率を高めてクエリ処理を高速化するために、転置インデックスの圧縮は必要不可欠となっている。 この記事では、転置インデックス、とくにポスティングリストの圧縮について、近年の手法を簡単にまとめる。 目次 転置インデックスの基本 転置インデックスのデータ構造と特性 転置インデックスのアクセスパターン 近年のインデックス圧縮技法 Variable-Byte Family VByte Varint-GB Varint-G8IU Masked-VByte Stream-VByte Opt-VByte Simple Family Simple9 Simple16
TL;DR; We are changing std::sort in LLVM’s libcxx. That’s a long story of what it took us to get there and all possible consequences, bugs you might encounter with examples from open source. We provide some benchmarks, perspective, why we did this in the first place and what it cost us with exciting ideas from Hyrum’s Law to reinforcement learning. All changes went into open source and thus I can
Over the course of my Spring 2020 semester at Harvey Mudd College, I developed a self-hosting compiler entirely from scratch. This article walks through many interesting parts of the project. It’s laid out so you can just read from beginning to end, but if you’re more interested in a particular topic, feel free to jump there. Or, take a look at the project on GitHub. Table of contents What the pro
Try Mastering Emacs for free! Are you struggling with the basics? Have you mastered movement and editing yet? When you have read Mastering Emacs you will understand Emacs. It’s that time again: there’s a new major version of Emacs and, with it, a treasure trove of new features and changes. Notable features include the formal inclusion of native compilation, a technique that will greatly speed up y
Rust Language Cheat Sheet 26. August 2021 Contains clickable links to The Book , Rust by Example , Std Docs , Nomicon , Reference . Data Structures Data types and memory locations defined via keywords. Example Explanation struct S {} Define a struct with named fields. struct S { x: T } Define struct with named field x of type T. struct S (T); Define "tupled" struct with numbered field .0 of type
Introduction: Density Is King (With a Tiny VM) I've previously come to the conclusion that there's little reason for using bytecode in the modern world, except in order to get more compact code, for which it can be very effective. So, what kind of a bytecode engine will give you more compact code? Suppose I want a bytecode interpreter for a very small programming environment, specifically to minim
Clojure's deadly sin
This article is about laziness in Clojure. It is intended to be a comprehensive and objective (however possible) critique of lazy sequences as a feature. In no way do I want this to be a judgment of the decision to make Clojure lazy. Clojure the language is by no means formulaic; creating it involved making a plethora of impactful choices. We can judge by Clojure's longevity that the total package
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Changing std::sort at Google’s Scale and Beyond
Kalyn: a self-hosting compiler for x86-64
What's New in Emacs 28.1?
https://cheats.rs/rust_cheat_sheet.pdf
bytecode interpreters for tiny computers ⁑ Dercuano