tink
/
dev-wiki
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
main
Branches Tags
${ item.name }
Create tag ${ searchTerm }
Create branch ${ searchTerm }
from '0b2d19ca47'
${ noResults }
dev-wiki/site/qa/queue/index.html

3092 lines
73 KiB
HTML
Raw Blame History Unescape Escape

This file contains ambiguous Unicode characters!

This file contains ambiguous Unicode characters that may be confused with others in your current locale. If your use case is intentional and legitimate, you can safely ignore this warning. Use the Escape button to highlight these characters.

<!doctype html>
<html lang="zh" class="no-js">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<meta name="description" content="开发知识wiki">
<meta name="author" content="tink">
<link rel="canonical" href="https://docs.cyub.vip/dev-wiki/qa/queue/">
<link rel="prev" href="../nginx/">
<link rel="next" href="../io/">
<link rel="icon" href="../../images/favicon.ico">
<meta name="generator" content="mkdocs-1.5.3, mkdocs-material-9.4.4">
<title>消息队列 - 开发知识wiki</title>
<link rel="stylesheet" href="../../assets/stylesheets/main.bd3936ea.min.css">
<link rel="stylesheet" href="../../assets/stylesheets/palette.356b1318.min.css">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Fira+Code:300,300i,400,400i,700,700i%7CFira+Code:400,400i,700,700i&display=fallback">
<style>:root{--md-text-font:"Fira Code";--md-code-font:"Fira Code"}</style>
<link rel="stylesheet" href="../../css/print-site-enum-headings1.css">
<link rel="stylesheet" href="../../css/print-site-enum-headings2.css">
<link rel="stylesheet" href="../../css/print-site-enum-headings3.css">
<link rel="stylesheet" href="../../css/print-site-enum-headings4.css">
<link rel="stylesheet" href="../../css/print-site-enum-headings5.css">
<link rel="stylesheet" href="../../css/print-site-enum-headings6.css">
<link rel="stylesheet" href="../../css/print-site.css">
<link rel="stylesheet" href="../../css/print-site-material.css">
<script>__md_scope=new URL("../..",location),__md_hash=e=>[...e].reduce((e,_)=>(e<<5)-e+_.charCodeAt(0),0),__md_get=(e,_=localStorage,t=__md_scope)=>JSON.parse(_.getItem(t.pathname+"."+e)),__md_set=(e,_,t=localStorage,a=__md_scope)=>{try{t.setItem(a.pathname+"."+e,JSON.stringify(_))}catch(e){}}</script>
<script id="__analytics">function __md_analytics(){function n(){dataLayer.push(arguments)}window.dataLayer=window.dataLayer||[],n("js",new Date),n("config",""),document.addEventListener("DOMContentLoaded",function(){document.forms.search&&document.forms.search.query.addEventListener("blur",function(){this.value&&n("event","search",{search_term:this.value})}),document$.subscribe(function(){var a=document.forms.feedback;if(void 0!==a)for(var e of a.querySelectorAll("[type=submit]"))e.addEventListener("click",function(e){e.preventDefault();var t=document.location.pathname,e=this.getAttribute("data-md-value");n("event","feedback",{page:t,data:e}),a.firstElementChild.disabled=!0;e=a.querySelector(".md-feedback__note [data-md-value='"+e+"']");e&&(e.hidden=!1)}),a.hidden=!1}),location$.subscribe(function(e){n("config","",{page_path:e.pathname})})});var e=document.createElement("script");e.async=!0,e.src="https://www.googletagmanager.com/gtag/js?id=",document.getElementById("__analytics").insertAdjacentElement("afterEnd",e)}</script>
<script>"undefined"!=typeof __md_analytics&&__md_analytics()</script>
<link href="../../assets/stylesheets/glightbox.min.css" rel="stylesheet"/><style>
html.glightbox-open { overflow: initial; height: 100%; }
.gslide-title { margin-top: 0px; user-select: text; }
.gslide-desc { color: #666; user-select: text; }
.gslide-image img { background: white; }
.gscrollbar-fixer { padding-right: 15px; }
.gdesc-inner { font-size: 0.75rem; }
body[data-md-color-scheme="slate"] .gdesc-inner { background: var(--md-default-bg-color);}
body[data-md-color-scheme="slate"] .gslide-title { color: var(--md-default-fg-color);}
body[data-md-color-scheme="slate"] .gslide-desc { color: var(--md-default-fg-color);}</style> <script src="../../assets/javascripts/glightbox.min.js"></script></head>
<body dir="ltr" data-md-color-scheme="default" data-md-color-primary="indigo" data-md-color-accent="indigo">
<script>var palette=__md_get("__palette");if(palette&&"object"==typeof palette.color)for(var key of Object.keys(palette.color))document.body.setAttribute("data-md-color-"+key,palette.color[key])</script>
<input class="md-toggle" data-md-toggle="drawer" type="checkbox" id="__drawer" autocomplete="off">
<input class="md-toggle" data-md-toggle="search" type="checkbox" id="__search" autocomplete="off">
<label class="md-overlay" for="__drawer"></label>
<div data-md-component="skip">
<a href="#_1" class="md-skip">
跳转至
</a>
</div>
<div data-md-component="announce">
</div>
<header class="md-header" data-md-component="header">
<nav class="md-header__inner md-grid" aria-label="页眉">
<a href="../.." title="开发知识wiki" class="md-header__button md-logo" aria-label="开发知识wiki" data-md-component="logo">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 89 89">
<path d="M3.136,17.387l0,42.932l42.932,21.467l-42.932,-64.399Z" />
<path d="M21.91,8l42.933,64.398l-18.775,9.388l-42.932,-64.399l18.774,-9.387Z" style="fill-opacity: 0.5" />
<path d="M67.535,17.387l-27.262,18.156l21.878,32.818l5.384,2.691l0,-53.665Z" />
<path d="M67.535,17.387l0,53.666l18.774,-9.388l0,-53.665l-18.774,9.387Z" style="fill-opacity: 0.25" />
</svg>
</a>
<label class="md-header__button md-icon" for="__drawer">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M3 6h18v2H3V6m0 5h18v2H3v-2m0 5h18v2H3v-2Z"/></svg>
</label>
<div class="md-header__title" data-md-component="header-title">
<div class="md-header__ellipsis">
<div class="md-header__topic">
<span class="md-ellipsis">
开发知识wiki
</span>
</div>
<div class="md-header__topic" data-md-component="header-topic">
<span class="md-ellipsis">
消息队列
</span>
</div>
</div>
</div>
<form class="md-header__option" data-md-component="palette">
<input class="md-option" data-md-color-media="(prefers-color-scheme)" data-md-color-scheme="default" data-md-color-primary="indigo" data-md-color-accent="indigo" aria-label="Switch to light mode" type="radio" name="__palette" id="__palette_1">
<label class="md-header__button md-icon" title="Switch to light mode" for="__palette_3" hidden>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M3.9 12c0-1.71 1.39-3.1 3.1-3.1h4V7H7a5 5 0 0 0-5 5 5 5 0 0 0 5 5h4v-1.9H7c-1.71 0-3.1-1.39-3.1-3.1M8 13h8v-2H8v2m9-6h-4v1.9h4c1.71 0 3.1 1.39 3.1 3.1 0 1.71-1.39 3.1-3.1 3.1h-4V17h4a5 5 0 0 0 5-5 5 5 0 0 0-5-5Z"/></svg>
</label>
<input class="md-option" data-md-color-media="(prefers-color-scheme: light)" data-md-color-scheme="default" data-md-color-primary="indigo" data-md-color-accent="indigo" aria-label="Switch to dark mode" type="radio" name="__palette" id="__palette_2">
<label class="md-header__button md-icon" title="Switch to dark mode" for="__palette_1" hidden>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M17 7H7a5 5 0 0 0-5 5 5 5 0 0 0 5 5h10a5 5 0 0 0 5-5 5 5 0 0 0-5-5m0 8a3 3 0 0 1-3-3 3 3 0 0 1 3-3 3 3 0 0 1 3 3 3 3 0 0 1-3 3Z"/></svg>
</label>
<input class="md-option" data-md-color-media="(prefers-color-scheme: dark)" data-md-color-scheme="slate" data-md-color-primary="black" data-md-color-accent="indigo" aria-label="Switch to system preference" type="radio" name="__palette" id="__palette_3">
<label class="md-header__button md-icon" title="Switch to system preference" for="__palette_2" hidden>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M17 7H7a5 5 0 0 0-5 5 5 5 0 0 0 5 5h10a5 5 0 0 0 5-5 5 5 0 0 0-5-5M7 15a3 3 0 0 1-3-3 3 3 0 0 1 3-3 3 3 0 0 1 3 3 3 3 0 0 1-3 3Z"/></svg>
</label>
</form>
<label class="md-header__button md-icon" for="__search">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M9.5 3A6.5 6.5 0 0 1 16 9.5c0 1.61-.59 3.09-1.56 4.23l.27.27h.79l5 5-1.5 1.5-5-5v-.79l-.27-.27A6.516 6.516 0 0 1 9.5 16 6.5 6.5 0 0 1 3 9.5 6.5 6.5 0 0 1 9.5 3m0 2C7 5 5 7 5 9.5S7 14 9.5 14 14 12 14 9.5 12 5 9.5 5Z"/></svg>
</label>
<div class="md-search" data-md-component="search" role="dialog">
<label class="md-search__overlay" for="__search"></label>
<div class="md-search__inner" role="search">
<form class="md-search__form" name="search">
<input type="text" class="md-search__input" name="query" aria-label="搜索" placeholder="搜索" autocapitalize="off" autocorrect="off" autocomplete="off" spellcheck="false" data-md-component="search-query" required>
<label class="md-search__icon md-icon" for="__search">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M9.5 3A6.5 6.5 0 0 1 16 9.5c0 1.61-.59 3.09-1.56 4.23l.27.27h.79l5 5-1.5 1.5-5-5v-.79l-.27-.27A6.516 6.516 0 0 1 9.5 16 6.5 6.5 0 0 1 3 9.5 6.5 6.5 0 0 1 9.5 3m0 2C7 5 5 7 5 9.5S7 14 9.5 14 14 12 14 9.5 12 5 9.5 5Z"/></svg>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M20 11v2H8l5.5 5.5-1.42 1.42L4.16 12l7.92-7.92L13.5 5.5 8 11h12Z"/></svg>
</label>
<nav class="md-search__options" aria-label="查找">
<a href="javascript:void(0)" class="md-search__icon md-icon" title="分享" aria-label="分享" data-clipboard data-clipboard-text="" data-md-component="search-share" tabindex="-1">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M18 16.08c-.76 0-1.44.3-1.96.77L8.91 12.7c.05-.23.09-.46.09-.7 0-.24-.04-.47-.09-.7l7.05-4.11c.54.5 1.25.81 2.04.81a3 3 0 0 0 3-3 3 3 0 0 0-3-3 3 3 0 0 0-3 3c0 .24.04.47.09.7L8.04 9.81C7.5 9.31 6.79 9 6 9a3 3 0 0 0-3 3 3 3 0 0 0 3 3c.79 0 1.5-.31 2.04-.81l7.12 4.15c-.05.21-.08.43-.08.66 0 1.61 1.31 2.91 2.92 2.91 1.61 0 2.92-1.3 2.92-2.91A2.92 2.92 0 0 0 18 16.08Z"/></svg>
</a>
<button type="reset" class="md-search__icon md-icon" title="清空当前内容" aria-label="清空当前内容" tabindex="-1">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41Z"/></svg>
</button>
</nav>
<div class="md-search__suggest" data-md-component="search-suggest"></div>
</form>
<div class="md-search__output">
<div class="md-search__scrollwrap" data-md-scrollfix>
<div class="md-search-result" data-md-component="search-result">
<div class="md-search-result__meta">
正在初始化搜索引擎
</div>
<ol class="md-search-result__list" role="presentation"></ol>
</div>
</div>
</div>
</div>
</div>
</nav>
</header>
<div class="md-container" data-md-component="container">
<nav class="md-tabs" aria-label="标签" data-md-component="tabs">
<div class="md-grid">
<ul class="md-tabs__list">
<li class="md-tabs__item">
<a href="../.." class="md-tabs__link">
简介
</a>
</li>
<li class="md-tabs__item">
<a href="../../computer-system/io/" class="md-tabs__link">
操作系统
</a>
</li>
<li class="md-tabs__item">
<a href="../../computer-network/tcp/" class="md-tabs__link">
计算机网络
</a>
</li>
<li class="md-tabs__item">
<a href="../../database/mysql/%E7%AE%80%E4%BB%8B/" class="md-tabs__link">
数据库
</a>
</li>
<li class="md-tabs__item">
<a href="../../language/Go/" class="md-tabs__link">
开发语言
</a>
</li>
<li class="md-tabs__item">
<a href="../../system-design/" class="md-tabs__link">
系统设计
</a>
</li>
<li class="md-tabs__item">
<a href="../../jupyter/Go-Frameworks-Github-Fork-Stats/" class="md-tabs__link">
Jupyter
</a>
</li>
<li class="md-tabs__item">
<a href="../../video/os/" class="md-tabs__link">
视频
</a>
</li>
<li class="md-tabs__item md-tabs__item--active">
<a href="../redis/" class="md-tabs__link">
QA
</a>
</li>
</ul>
</div>
</nav>
<main class="md-main" data-md-component="main">
<div class="md-main__inner md-grid">
<div class="md-sidebar md-sidebar--primary" data-md-component="sidebar" data-md-type="navigation" >
<div class="md-sidebar__scrollwrap">
<div class="md-sidebar__inner">
<nav class="md-nav md-nav--primary md-nav--lifted" aria-label="导航栏" data-md-level="0">
<label class="md-nav__title" for="__drawer">
<a href="../.." title="开发知识wiki" class="md-nav__button md-logo" aria-label="开发知识wiki" data-md-component="logo">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 89 89">
<path d="M3.136,17.387l0,42.932l42.932,21.467l-42.932,-64.399Z" />
<path d="M21.91,8l42.933,64.398l-18.775,9.388l-42.932,-64.399l18.774,-9.387Z" style="fill-opacity: 0.5" />
<path d="M67.535,17.387l-27.262,18.156l21.878,32.818l5.384,2.691l0,-53.665Z" />
<path d="M67.535,17.387l0,53.666l18.774,-9.388l0,-53.665l-18.774,9.387Z" style="fill-opacity: 0.25" />
</svg>
</a>
开发知识wiki
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../.." class="md-nav__link">
<span class="md-ellipsis">
简介
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--section md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_2" >
<label class="md-nav__link" for="__nav_2" id="__nav_2_label" tabindex="">
<span class="md-ellipsis">
操作系统
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_2_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_2">
<span class="md-nav__icon md-icon"></span>
操作系统
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../computer-system/io/" class="md-nav__link">
<span class="md-ellipsis">
IO
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../computer-system/proc/" class="md-nav__link">
<span class="md-ellipsis">
proc文件系统
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../computer-system/nptl/" class="md-nav__link">
<span class="md-ellipsis">
NPTL
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--section md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_2_4" >
<label class="md-nav__link" for="__nav_2_4" id="__nav_2_4_label" tabindex="">
<span class="md-ellipsis">
容器
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="2" aria-labelledby="__nav_2_4_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_2_4">
<span class="md-nav__icon md-icon"></span>
容器
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../container/install/" class="md-nav__link">
<span class="md-ellipsis">
简介
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../container/image/" class="md-nav__link">
<span class="md-ellipsis">
镜像
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../container/cgroup/" class="md-nav__link">
<span class="md-ellipsis">
cgroup
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../container/namespace/" class="md-nav__link">
<span class="md-ellipsis">
namespace
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../../computer-system/command/" class="md-nav__link">
<span class="md-ellipsis">
常用命令
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../computer-system/systemtap/" class="md-nav__link">
<span class="md-ellipsis">
Systemtap
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../computer-system/cpu-arch/" class="md-nav__link">
<span class="md-ellipsis">
CPU架构
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../computer-system/compiling-linux-kernel/" class="md-nav__link">
<span class="md-ellipsis">
编译Linux内核
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--section md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_3" >
<div class="md-nav__link md-nav__container">
<a href="../../computer-network/tcp/" class="md-nav__link ">
<span class="md-ellipsis">
计算机网络
</span>
</a>
<label class="md-nav__link " for="__nav_3" id="__nav_3_label" tabindex="">
<span class="md-nav__icon md-icon"></span>
</label>
</div>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_3_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_3">
<span class="md-nav__icon md-icon"></span>
计算机网络
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../computer-network/http/" class="md-nav__link">
<span class="md-ellipsis">
HTTP
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--section md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_4" >
<label class="md-nav__link" for="__nav_4" id="__nav_4_label" tabindex="">
<span class="md-ellipsis">
数据库
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_4_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_4">
<span class="md-nav__icon md-icon"></span>
数据库
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item md-nav__item--section md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_4_1" >
<label class="md-nav__link" for="__nav_4_1" id="__nav_4_1_label" tabindex="">
<span class="md-ellipsis">
mysql
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="2" aria-labelledby="__nav_4_1_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_4_1">
<span class="md-nav__icon md-icon"></span>
mysql
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../database/mysql/%E7%AE%80%E4%BB%8B/" class="md-nav__link">
<span class="md-ellipsis">
概览
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../database/mysql/%E4%BA%8B%E5%8A%A1/" class="md-nav__link">
<span class="md-ellipsis">
事务
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../database/mysql/%E7%B4%A2%E5%BC%95/" class="md-nav__link">
<span class="md-ellipsis">
索引
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../database/mysql/FAQ/" class="md-nav__link">
<span class="md-ellipsis">
FAQ
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--section md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_4_2" >
<div class="md-nav__link md-nav__container">
<a href="../../database/elasticsearch/" class="md-nav__link ">
<span class="md-ellipsis">
Elasticsearch
</span>
</a>
<label class="md-nav__link " for="__nav_4_2" id="__nav_4_2_label" tabindex="">
<span class="md-nav__icon md-icon"></span>
</label>
</div>
<nav class="md-nav" data-md-level="2" aria-labelledby="__nav_4_2_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_4_2">
<span class="md-nav__icon md-icon"></span>
Elasticsearch
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../database/elasticsearch/memory/" class="md-nav__link">
<span class="md-ellipsis">
内存占用
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../database/elasticsearch/performance_tuning/" class="md-nav__link">
<span class="md-ellipsis">
性能调优
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../database/elasticsearch/production_configuring/" class="md-nav__link">
<span class="md-ellipsis">
生产配置参考
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../database/elasticsearch/doc_values_and_fielddata/" class="md-nav__link">
<span class="md-ellipsis">
docs value与 field data
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../../database/redis/redis/" class="md-nav__link">
<span class="md-ellipsis">
Redis
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--section md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_5" >
<label class="md-nav__link" for="__nav_5" id="__nav_5_label" tabindex="">
<span class="md-ellipsis">
开发语言
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_5_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_5">
<span class="md-nav__icon md-icon"></span>
开发语言
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../language/Go/" class="md-nav__link">
<span class="md-ellipsis">
Go
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--section md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_6" >
<div class="md-nav__link md-nav__container">
<a href="../../system-design/" class="md-nav__link ">
<span class="md-ellipsis">
系统设计
</span>
</a>
<label class="md-nav__link " for="__nav_6" id="__nav_6_label" tabindex="">
<span class="md-nav__icon md-icon"></span>
</label>
</div>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_6_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_6">
<span class="md-nav__icon md-icon"></span>
系统设计
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../cache/" class="md-nav__link">
<span class="md-ellipsis">
缓存系统
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../system-design/system-design-primer/" class="md-nav__link">
<span class="md-ellipsis">
系统设计入门
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--section md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_6_4" >
<div class="md-nav__link md-nav__container">
<a href="../../what-should-you-know/" class="md-nav__link ">
<span class="md-ellipsis">
what you should know
</span>
</a>
<label class="md-nav__link " for="__nav_6_4" id="__nav_6_4_label" tabindex="">
<span class="md-nav__icon md-icon"></span>
</label>
</div>
<nav class="md-nav" data-md-level="2" aria-labelledby="__nav_6_4_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_6_4">
<span class="md-nav__icon md-icon"></span>
what you should know
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../what-should-you-know/GPU/" class="md-nav__link">
<span class="md-ellipsis">
每个开发人员都应该了解 GPU 计算的知识
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../what-should-you-know/hardware/" class="md-nav__link">
<span class="md-ellipsis">
每个程序员都应该了解的硬件知识
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_6_4_4" >
<label class="md-nav__link" for="__nav_6_4_4" id="__nav_6_4_4_label" tabindex="0">
<span class="md-ellipsis">
每个程序员都应该了解的内存知识
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="3" aria-labelledby="__nav_6_4_4_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_6_4_4">
<span class="md-nav__icon md-icon"></span>
每个程序员都应该了解的内存知识
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../what-should-you-know/%E6%AF%8F%E4%B8%AA%E7%A8%8B%E5%BA%8F%E5%91%98%E9%83%BD%E5%BA%94%E8%AF%A5%E4%BA%86%E8%A7%A3%E7%9A%84%E5%86%85%E5%AD%98%E7%9F%A5%E8%AF%86/" class="md-nav__link">
<span class="md-ellipsis">
【总结版】每个程序员都应该了解的内存知识
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../what-should-you-know/What%20Every%20Programmer%20Should%20Know%20About%20Memory.pdf" class="md-nav__link">
<span class="md-ellipsis">
【英文】What Every Programmer Should Know About Memory
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../what-should-you-know/%E6%AF%8F%E4%B8%AA%E7%A8%8B%E5%BA%8F%E5%91%98%E9%83%BD%E5%BA%94%E8%AF%A5%E4%BA%86%E8%A7%A3%E7%9A%84%E5%86%85%E5%AD%98%E7%9F%A5%E8%AF%86.pdf" class="md-nav__link">
<span class="md-ellipsis">
【中文】每个程序员都应该了解的内存知识
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_6_4_5" >
<label class="md-nav__link" for="__nav_6_4_5" id="__nav_6_4_5_label" tabindex="0">
<span class="md-ellipsis">
每个系统程序员都应该了解的并发知识
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="3" aria-labelledby="__nav_6_4_5_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_6_4_5">
<span class="md-nav__icon md-icon"></span>
每个系统程序员都应该了解的并发知识
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../what-should-you-know/concurrency-primer.pdf" class="md-nav__link">
<span class="md-ellipsis">
【英文】What every systems programmer should know about concurrency
</span>
</a>
</li>
<li class="md-nav__item">
<a href="https://www.bilibili.com/read/cv26734224" class="md-nav__link">
<span class="md-ellipsis">
【中文】每个系统程序员都应该了解的并发知识
</span>
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--section md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_7" >
<label class="md-nav__link" for="__nav_7" id="__nav_7_label" tabindex="">
<span class="md-ellipsis">
Jupyter
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_7_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_7">
<span class="md-nav__icon md-icon"></span>
Jupyter
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../jupyter/Go-Frameworks-Github-Fork-Stats/" class="md-nav__link">
<span class="md-ellipsis">
Go-Frameworks-Github-Fork-Stats
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../jupyter/Pandas%E5%AE%8C%E5%85%A8%E6%8C%87%E5%8D%97/" class="md-nav__link">
<span class="md-ellipsis">
Pandas完全指南
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--section md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_7_3" >
<label class="md-nav__link" for="__nav_7_3" id="__nav_7_3_label" tabindex="">
<span class="md-ellipsis">
Spark上手示例
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="2" aria-labelledby="__nav_7_3_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_7_3">
<span class="md-nav__icon md-icon"></span>
Spark上手示例
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../jupyter/Spark%E4%B8%8A%E6%89%8B%E7%A4%BA%E4%BE%8B1%EF%BC%9ARDD%E6%93%8D%E4%BD%9C/" class="md-nav__link">
<span class="md-ellipsis">
Spark上手示例1：RDD操作
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../jupyter/Spark%E4%B8%8A%E6%89%8B%E7%A4%BA%E4%BE%8B2%EF%BC%9ADataFrame%E6%93%8D%E4%BD%9C/" class="md-nav__link">
<span class="md-ellipsis">
Spark上手示例2：DataFrame操作
</span>
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--section md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_8" >
<label class="md-nav__link" for="__nav_8" id="__nav_8_label" tabindex="">
<span class="md-ellipsis">
视频
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_8_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_8">
<span class="md-nav__icon md-icon"></span>
视频
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../video/os/" class="md-nav__link">
<span class="md-ellipsis">
操作系统
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../video/Data%20structures/" class="md-nav__link">
<span class="md-ellipsis">
数据结构与算法
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../video/c_c%2B%2B/" class="md-nav__link">
<span class="md-ellipsis">
C/C++
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../video/Go/" class="md-nav__link">
<span class="md-ellipsis">
Go
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--active md-nav__item--section md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_9" checked>
<label class="md-nav__link" for="__nav_9" id="__nav_9_label" tabindex="">
<span class="md-ellipsis">
QA
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_9_label" aria-expanded="true">
<label class="md-nav__title" for="__nav_9">
<span class="md-nav__icon md-icon"></span>
QA
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../redis/" class="md-nav__link">
<span class="md-ellipsis">
redis
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../mysql/" class="md-nav__link">
<span class="md-ellipsis">
mysql
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../tcp/" class="md-nav__link">
<span class="md-ellipsis">
tcp
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../http/" class="md-nav__link">
<span class="md-ellipsis">
http
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../cache/" class="md-nav__link">
<span class="md-ellipsis">
缓存
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../nginx/" class="md-nav__link">
<span class="md-ellipsis">
nginx
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--active">
<input class="md-nav__toggle md-toggle" type="checkbox" id="__toc">
<label class="md-nav__link md-nav__link--active" for="__toc">
<span class="md-ellipsis">
消息队列
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<a href="./" class="md-nav__link md-nav__link--active">
<span class="md-ellipsis">
消息队列
</span>
</a>
<nav class="md-nav md-nav--secondary" aria-label="目录">
<label class="md-nav__title" for="__toc">
<span class="md-nav__icon md-icon"></span>
目录
</label>
<ul class="md-nav__list" data-md-component="toc" data-md-scrollfix>
<li class="md-nav__item">
<a href="#_2" class="md-nav__link">
为什么要使用消息队列？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka" class="md-nav__link">
kafka是什么？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka_1" class="md-nav__link">
kafka如何做到高可用的？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka_2" class="md-nav__link">
Kafka 为什么不支持读写分离?
</a>
</li>
<li class="md-nav__item">
<a href="#kafka_3" class="md-nav__link">
如何解决kafka消息重复消费问题？
</a>
</li>
<li class="md-nav__item">
<a href="#kafkapullpush" class="md-nav__link">
Kafka消息是采用Pull模式，还是Push模式？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka_4" class="md-nav__link">
kafka中如何防止消息丢失？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka-zookeeper-zookeeper" class="md-nav__link">
kafka中的 zookeeper 起到什么作用，可以不用zookeeper吗？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka_5" class="md-nav__link">
kafka 为什么那么快？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka_6" class="md-nav__link">
Kafka中是怎么体现消息顺序性的？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka_7" class="md-nav__link">
kafka如何实现延迟队列？
</a>
</li>
<li class="md-nav__item">
<a href="#kafkaconsumer-group" class="md-nav__link">
kafka中consumer group 是什么概念？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka-offset" class="md-nav__link">
Kafka 中位移(offset)的作用？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka-leader-replica-follower-replica" class="md-nav__link">
阐述下Kafka 中的领导者副本(Leader Replica)和追随者副本 (Follower Replica)的区别？
</a>
</li>
<li class="md-nav__item">
<a href="#_3" class="md-nav__link">
消息传递语义是什么概念？
</a>
</li>
<li class="md-nav__item">
<a href="#beanstalk" class="md-nav__link">
介绍一下beanstalk?
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../io/" class="md-nav__link">
<span class="md-ellipsis">
IO
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../protobuf/" class="md-nav__link">
<span class="md-ellipsis">
protobuf
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../go/" class="md-nav__link">
<span class="md-ellipsis">
go
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../dist/" class="md-nav__link">
<span class="md-ellipsis">
分布式
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../es/" class="md-nav__link">
<span class="md-ellipsis">
Elasticsearch
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../docker/" class="md-nav__link">
<span class="md-ellipsis">
docker
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../ref/" class="md-nav__link">
<span class="md-ellipsis">
参考资料
</span>
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</div>
</div>
</div>
<div class="md-sidebar md-sidebar--secondary" data-md-component="sidebar" data-md-type="toc" >
<div class="md-sidebar__scrollwrap">
<div class="md-sidebar__inner">
<nav class="md-nav md-nav--secondary" aria-label="目录">
<label class="md-nav__title" for="__toc">
<span class="md-nav__icon md-icon"></span>
目录
</label>
<ul class="md-nav__list" data-md-component="toc" data-md-scrollfix>
<li class="md-nav__item">
<a href="#_2" class="md-nav__link">
为什么要使用消息队列？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka" class="md-nav__link">
kafka是什么？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka_1" class="md-nav__link">
kafka如何做到高可用的？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka_2" class="md-nav__link">
Kafka 为什么不支持读写分离?
</a>
</li>
<li class="md-nav__item">
<a href="#kafka_3" class="md-nav__link">
如何解决kafka消息重复消费问题？
</a>
</li>
<li class="md-nav__item">
<a href="#kafkapullpush" class="md-nav__link">
Kafka消息是采用Pull模式，还是Push模式？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka_4" class="md-nav__link">
kafka中如何防止消息丢失？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka-zookeeper-zookeeper" class="md-nav__link">
kafka中的 zookeeper 起到什么作用，可以不用zookeeper吗？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka_5" class="md-nav__link">
kafka 为什么那么快？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka_6" class="md-nav__link">
Kafka中是怎么体现消息顺序性的？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka_7" class="md-nav__link">
kafka如何实现延迟队列？
</a>
</li>
<li class="md-nav__item">
<a href="#kafkaconsumer-group" class="md-nav__link">
kafka中consumer group 是什么概念？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka-offset" class="md-nav__link">
Kafka 中位移(offset)的作用？
</a>
</li>
<li class="md-nav__item">
<a href="#kafka-leader-replica-follower-replica" class="md-nav__link">
阐述下Kafka 中的领导者副本(Leader Replica)和追随者副本 (Follower Replica)的区别？
</a>
</li>
<li class="md-nav__item">
<a href="#_3" class="md-nav__link">
消息传递语义是什么概念？
</a>
</li>
<li class="md-nav__item">
<a href="#beanstalk" class="md-nav__link">
介绍一下beanstalk?
</a>
</li>
</ul>
</nav>
</div>
</div>
</div>
<div class="md-content" data-md-component="content">
<article class="md-content__inner md-typeset">
<h1 id="_1">消息队列<a class="headerlink" href="#_1" title="Permanent link">&para;</a></h1>
<h2 id="_2">为什么要使用消息队列？<a class="headerlink" href="#_2" title="Permanent link">&para;</a></h2>
<ol>
<li>业务解耦</li>
<li>异步处理</li>
<li>流量削峰</li>
</ol>
<h2 id="kafka">kafka是什么？<a class="headerlink" href="#kafka" title="Permanent link">&para;</a></h2>
<p>Kafka是高吞吐低延迟的高并发、高性能的消息中间件，配置良好的Kafka集群甚至可以做到每秒几十万、上百万的超高并发写入。Kafka是**一个分布式消息队列**。Kafka对消息保存时根据Topic进行归类，发送消息者称为Producer，消息接受者称为Consumer，此外kafka集群有多个kafka实例组成，每个实例(server)称为broker。无论是kafka集群，还是consumer都依赖于zookeeper集群保存一些meta信息，来保证系统可用性。</p>
<p><a class="glightbox" href="https://static.cyub.vip/images/202107/kafka_arch.png" data-type="image" data-width="auto" data-height="auto" data-desc-position="bottom"><img alt="" src="https://static.cyub.vip/images/202107/kafka_arch.png" /></a></p>
<h2 id="kafka_1">kafka如何做到高可用的？<a class="headerlink" href="#kafka_1" title="Permanent link">&para;</a></h2>
<p>从topic的Partition的副本来看：</p>
<p><a class="glightbox" href="https://static.cyub.vip/images/202107/kafka_ha.jpeg" data-type="image" data-width="auto" data-height="auto" data-desc-position="bottom"><img alt="" src="https://static.cyub.vip/images/202107/kafka_ha.jpeg" /></a></p>
<p>上图中只有一个Topic，它有3个Partition。</p>
<h2 id="kafka_2">Kafka 为什么不支持读写分离?<a class="headerlink" href="#kafka_2" title="Permanent link">&para;</a></h2>
<p>自 Kafka 2.4 之后，Kafka 提供了有限度的读写分离，也就是说，Follower 副本能够对外提供读服务。</p>
<ol>
<li>业务场景不适用。读写分离适用于那种读负载很大，而写操作相对不频繁的场景，可 Kafka 不属于这样的场景。</li>
<li>同步机制。Kafka 采用 PULL 方式实现 Follower 的同步，因此Follower 与 Leader 存 在不一致性窗口。如果允许读 Follower 副本，就势必要处理消息滞后(Lagging)的问题。</li>
</ol>
<h2 id="kafka_3">如何解决kafka消息重复消费问题？<a class="headerlink" href="#kafka_3" title="Permanent link">&para;</a></h2>
<p>将消息的唯一标识保存到外部介质中，每次消费时判断是否处理过即可。这个解决办法适合其他消息系统。</p>
<h2 id="kafkapullpush">Kafka消息是采用Pull模式，还是Push模式？<a class="headerlink" href="#kafkapullpush" title="Permanent link">&para;</a></h2>
<p>kafka遵循了一种大部分消息系统共同的传统的设计：producer将消息推送(push)到broker，consumer从broker拉取(pull)消息。同redis的bpop命令类似，Kafka有个参数可以让consumer阻塞知道新消息到达，可以防止consumer不断在循环中轮询。</p>
<h2 id="kafka_4">kafka中如何防止消息丢失？<a class="headerlink" href="#kafka_4" title="Permanent link">&para;</a></h2>
<p>Kafka消息发送有两种方式：同步（sync）和异步（async），默认是同步方式，可通过producer.type属性进行配置。Kafka通过配置request.required.acks属性来确认消息的生产：</p>
<ul>
<li>
<p>0</p>
<p>表示producer不等待来自broker同步完成的确认继续发送下一条消息；</p>
</li>
<li>
<p>1</p>
<p>表示producer在leader已成功收到的数据并得到确认后发送下一条message，默认状态</p>
</li>
<li>
<p>-1</p>
<p>表示producer在header,follower副本确认接收到数据后才算一次发送完成；</p>
</li>
</ul>
<p>综上所述，有6种消息生产的情况，下面分情况来分析消息丢失的场景：</p>
<p>（1）acks=0，不和Kafka集群进行消息接收确认，则当网络异常、缓冲区满了等情况时，消息可能丢失；</p>
<p>（2）acks=1、同步模式下，只有Leader确认接收成功后但挂掉了，副本没有同步，数据可能丢失；</p>
<p>可见在同步模式下，ack=-1时候，可以防止消息丢失。但这牺牲了吞吐量。</p>
<h2 id="kafka-zookeeper-zookeeper">kafka中的 zookeeper 起到什么作用，可以不用zookeeper吗？<a class="headerlink" href="#kafka-zookeeper-zookeeper" title="Permanent link">&para;</a></h2>
<p>早期版本的kafka用zk做meta信息存储，consumer的消费状态，group的管理以及 offset的值。新的consumer使用了kafka内部的group coordination协议，也减少了对zookeeper的依赖，但是broker依然依赖于ZK，zookeeper 在kafka中还用来选举controller 和 检测broker是否存活等等。</p>
<h2 id="kafka_5">kafka 为什么那么快？<a class="headerlink" href="#kafka_5" title="Permanent link">&para;</a></h2>
<ol>
<li>
<p>Page cache技术</p>
<p>Kafka每次接收到数据都会往磁盘上去写。但并不是直接写入磁盘的，而是写入OS cache上面，然后在写到磁盘</p>
</li>
<li>
<p>顺序读写磁盘</p>
<p>磁盘读写时候，是顺序读写的。此时数据在磁盘上存取代价为O(1)。</p>
</li>
<li>
<p>零拷贝技术</p>
<p>Customer从broker读取数据，采用零拷贝技术。将磁盘文件读到OS内核缓冲区后，直接转到socket buffer进行网络发送。</p>
<p>传统的数据发送需要发送4次上下文切换，采用sendfile系统调用之后，数据直接在内核态交换，系统上下文切换减少为2次。</p>
</li>
</ol>
<h2 id="kafka_6">Kafka中是怎么体现消息顺序性的？<a class="headerlink" href="#kafka_6" title="Permanent link">&para;</a></h2>
<p>kafka每个partition中的消息在写入时都是有序的，消费时，每个partition只能被每一个group中的一个消费者消费，保证了消费时也是有序的。整个topic不保证有序。如果为了保证topic整个有序，那么将partition调整为1。</p>
<h2 id="kafka_7">kafka如何实现延迟队列？<a class="headerlink" href="#kafka_7" title="Permanent link">&para;</a></h2>
<p>kafka基于**时间轮**可以将插入和删除操作的时间复杂度都降为O(1)。</p>
<h2 id="kafkaconsumer-group">kafka中consumer group 是什么概念？<a class="headerlink" href="#kafkaconsumer-group" title="Permanent link">&para;</a></h2>
<p>consumer group是Kafka实现单播和广播两种消息模型的手段。同一个topic的数据，会广播给不同的group；同一个group中的worker，只有一个worker能拿到这个数据。换句话说，对于同一个topic，每个group都可以拿到同样的所有数据，但是数据进入group后只能被其中的一个worker消费。group内的worker可以使用多线程或多进程来实现，也可以将进程分散在多台机器上，worker的数量通常不超过partition的数量，且二者最好保持整数倍关系，因为Kafka在设计时假定了一个partition只能被一个worker消费（同一group内）。</p>
<h2 id="kafka-offset">Kafka 中位移(offset)的作用？<a class="headerlink" href="#kafka-offset" title="Permanent link">&para;</a></h2>
<p>在 Kafka 中，每个 主题分区下的每条消息都被赋予了一个唯一的 ID 数值，用于标识它在分区中的位置。这个 ID 数值，就被称为位移，或者叫偏移量。一旦消息被写入到分区日志，它的位移值将不能 被修改。</p>
<h2 id="kafka-leader-replica-follower-replica">阐述下Kafka 中的领导者副本(Leader Replica)和追随者副本 (Follower Replica)的区别？<a class="headerlink" href="#kafka-leader-replica-follower-replica" title="Permanent link">&para;</a></h2>
<p>Kafka 副本当前分为领导者副本和追随者副本。只有 Leader 副本才能 对外提供读写服务，响应 Clients 端的请求。Follower 副本只是采用拉(PULL)的方 式，被动地同步 Leader 副本中的数据，并且在 Leader 副本所在的 Broker 宕机后，随时准备应聘 Leader 副本。</p>
<p>自 Kafka 2.4 版本开始，社区通过引入新的 Broker 端参数，允许 Follower 副本有限度地提供读服务。</p>
<h2 id="_3">消息传递语义是什么概念？<a class="headerlink" href="#_3" title="Permanent link">&para;</a></h2>
<p>message delivery semantic 也就是消息传递语义。通用的概念，也就是消息传递过程中消息传递的保证性。分为三种：</p>
<ul>
<li>
<p><strong>最多一次（at most once）</strong></p>
<p>消息可能丢失也可能被处理，但最多只会被处理一次。可能丢失，不会重复。</p>
<p><strong>只管发送，不管对方收没收到。</strong></p>
</li>
<li>
<p><strong>至少一次（at least once）</strong></p>
<p>消息不会丢失，但可能被处理多次。可能重复 不会丢失。</p>
<p><strong>发送之后，会等待对方确认之后才会停止发送。</strong></p>
</li>
<li>
<p><strong>精确传递一次（exactly once）</strong></p>
<p>消息被处理且只会被处理一次。不丢失，不重复，就一次。</p>
</li>
</ul>
<h2 id="beanstalk">介绍一下beanstalk?<a class="headerlink" href="#beanstalk" title="Permanent link">&para;</a></h2>
<p>beanstalk是轻量级的，易使用的，C语言实现的消息队列中间件。支持特性有：</p>
<ul>
<li>
<p>延迟（delay）</p>
<p>延迟意味着可以定义任务什么时间才开始被消费</p>
</li>
<li>
<p>优先级（priority）</p>
<p>优先级就意味 支持任务插队（数字越小，优先级越高，0的优先级最高）</p>
</li>
<li>
<p>持久化（persistent data）</p>
<p>Beanstalkd 支持定时将文件刷到日志文件里，即使beanstalkd宕机，重启之后仍然可以找回文件</p>
</li>
<li>
<p>任务超时重发（time-to-run）</p>
<p>消费者必须在指定的时间内处理完这个任务，否则就认为消费者处理失败，任务会被重新放到队列，等待消费</p>
</li>
</ul>
<p>Beanstalk由四部分构成：</p>
<ul>
<li>
<p>管道（tube）</p>
<p>相当于kafka的Topic概念，是消息的归类。</p>
</li>
<li>
<p>任务（job）</p>
<p>相当于kafka中的消息</p>
</li>
<li>
<p>producer</p>
<p>job的生产者，通过put命令来将一个job放到一个tube中</p>
</li>
<li>
<p>consumer</p>
<p>job的消费者，通过reserve、release、bury、delete命令来获取job或改变job的状态</p>
</li>
</ul>
<p>任务从进入管道到离开管道一共有5个状态（ready，delayed，reserved，buried，delete）：</p>
<ol>
<li>
<p>生产者将任务放到管道中，任务的状态可以是ready（表示任务已经准备好，随时可以被消费者读取），也可以是delayed（任务在被生产者放入管道时，设置了延迟，比如设置了5s延迟，意味着5s之后，这个任务才会变成ready状态，才可以被消费者读取）</p>
</li>
<li>
<p>消费者消费任务（消费者将处于ready状态的任务读出来后，被读取处理的任务状态变为reserved），可以设置reserved的时间，若在这段时间没有处理完成，那么任务会重新放回消息队列中，再次被别人消费</p>
</li>
<li>
<p>消费者处理完任务后，任务的状态可能是delete（删除，处理成功），可能是buried（预留，意味着先把任务放一边，等待条件成熟还要用），可能是ready，也可能是delayed，需要根据具体业务场景自己进行判断定义</p>
</li>
</ol>
<hr>
<div class="md-source-file">
<small>
最后更新:
<span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-iso_date">2024-06-04</span>
</small>
</div>
</article>
</div>
</div>
<button type="button" class="md-top md-icon" data-md-component="top" hidden>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8v12Z"/></svg>
回到页面顶部
</button>
</main>
<footer class="md-footer">
<nav class="md-footer__inner md-grid" aria-label="页脚" >
<a href="../nginx/" class="md-footer__link md-footer__link--prev" aria-label="上一页: nginx">
<div class="md-footer__button md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M20 11v2H8l5.5 5.5-1.42 1.42L4.16 12l7.92-7.92L13.5 5.5 8 11h12Z"/></svg>
</div>
<div class="md-footer__title">
<span class="md-footer__direction">
上一页
</span>
<div class="md-ellipsis">
nginx
</div>
</div>
</a>
<a href="../io/" class="md-footer__link md-footer__link--next" aria-label="下一页: IO">
<div class="md-footer__title">
<span class="md-footer__direction">
下一页
</span>
<div class="md-ellipsis">
IO
</div>
</div>
<div class="md-footer__button md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M4 11v2h12l-5.5 5.5 1.42 1.42L19.84 12l-7.92-7.92L10.5 5.5 16 11H4Z"/></svg>
</div>
</a>
</nav>
<div class="md-footer-meta md-typeset">
<div class="md-footer-meta__inner md-grid">
<div class="md-copyright">
<div class="md-copyright__highlight">
Copyright &copy; 2023 - 2024 Tink
</div>
Made with
<a href="https://squidfunk.github.io/mkdocs-material/" target="_blank" rel="noopener">
Material for MkDocs
</a>
</div>
<div class="md-social">
<a href="https://github.com/squidfunk" target="_blank" rel="noopener" title="github.com" class="md-social__link">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 496 512"><!--! Font Awesome Free 6.4.2 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2023 Fonticons, Inc.--><path d="M165.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6zm-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3zm44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9zM244.8 8C106.1 8 0 113.3 0 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C428.2 457.8 496 362.9 496 252 496 113.3 383.5 8 244.8 8zM97.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1zm-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7zm32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1zm-11.4-14.7c-1.6 1-1.6 3.6 0 5.9 1.6 2.3 4.3 3.3 5.6 2.3 1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2z"/></svg>
</a>
<a href="https://hub.docker.com/r/squidfunk/mkdocs-material/" target="_blank" rel="noopener" title="hub.docker.com" class="md-social__link">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 640 512"><!--! Font Awesome Free 6.4.2 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2023 Fonticons, Inc.--><path d="M349.9 236.3h-66.1v-59.4h66.1v59.4zm0-204.3h-66.1v60.7h66.1V32zm78.2 144.8H362v59.4h66.1v-59.4zm-156.3-72.1h-66.1v60.1h66.1v-60.1zm78.1 0h-66.1v60.1h66.1v-60.1zm276.8 100c-14.4-9.7-47.6-13.2-73.1-8.4-3.3-24-16.7-44.9-41.1-63.7l-14-9.3-9.3 14c-18.4 27.8-23.4 73.6-3.7 103.8-8.7 4.7-25.8 11.1-48.4 10.7H2.4c-8.7 50.8 5.8 116.8 44 162.1 37.1 43.9 92.7 66.2 165.4 66.2 157.4 0 273.9-72.5 328.4-204.2 21.4.4 67.6.1 91.3-45.2 1.5-2.5 6.6-13.2 8.5-17.1l-13.3-8.9zm-511.1-27.9h-66v59.4h66.1v-59.4zm78.1 0h-66.1v59.4h66.1v-59.4zm78.1 0h-66.1v59.4h66.1v-59.4zm-78.1-72.1h-66.1v60.1h66.1v-60.1z"/></svg>
</a>
<a href="https://pypi.org/project/mkdocs-material/" target="_blank" rel="noopener" title="pypi.org" class="md-social__link">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!--! Font Awesome Free 6.4.2 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2023 Fonticons, Inc.--><path d="M439.8 200.5c-7.7-30.9-22.3-54.2-53.4-54.2h-40.1v47.4c0 36.8-31.2 67.8-66.8 67.8H172.7c-29.2 0-53.4 25-53.4 54.3v101.8c0 29 25.2 46 53.4 54.3 33.8 9.9 66.3 11.7 106.8 0 26.9-7.8 53.4-23.5 53.4-54.3v-40.7H226.2v-13.6h160.2c31.1 0 42.6-21.7 53.4-54.2 11.2-33.5 10.7-65.7 0-108.6zM286.2 404c11.1 0 20.1 9.1 20.1 20.3 0 11.3-9 20.4-20.1 20.4-11 0-20.1-9.2-20.1-20.4.1-11.3 9.1-20.3 20.1-20.3zM167.8 248.1h106.8c29.7 0 53.4-24.5 53.4-54.3V91.9c0-29-24.4-50.7-53.4-55.6-35.8-5.9-74.7-5.6-106.8.1-45.2 8-53.4 24.7-53.4 55.6v40.7h106.9v13.6h-147c-31.1 0-58.3 18.7-66.8 54.2-9.8 40.7-10.2 66.1 0 108.6 7.6 31.6 25.7 54.2 56.8 54.2H101v-48.8c0-35.3 30.5-66.4 66.8-66.4zm-6.7-142.6c-11.1 0-20.1-9.1-20.1-20.3.1-11.3 9-20.4 20.1-20.4 11 0 20.1 9.2 20.1 20.4s-9 20.3-20.1 20.3z"/></svg>
</a>
<a href="https://fosstodon.org/@squidfunk" target="_blank" rel="noopener me" title="fosstodon.org" class="md-social__link">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!--! Font Awesome Free 6.4.2 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2023 Fonticons, Inc.--><path d="M433 179.11c0-97.2-63.71-125.7-63.71-125.7-62.52-28.7-228.56-28.4-290.48 0 0 0-63.72 28.5-63.72 125.7 0 115.7-6.6 259.4 105.63 289.1 40.51 10.7 75.32 13 103.33 11.4 50.81-2.8 79.32-18.1 79.32-18.1l-1.7-36.9s-36.31 11.4-77.12 10.1c-40.41-1.4-83-4.4-89.63-54a102.54 102.54 0 0 1-.9-13.9c85.63 20.9 158.65 9.1 178.75 6.7 56.12-6.7 105-41.3 111.23-72.9 9.8-49.8 9-121.5 9-121.5zm-75.12 125.2h-46.63v-114.2c0-49.7-64-51.6-64 6.9v62.5h-46.33V197c0-58.5-64-56.6-64-6.9v114.2H90.19c0-122.1-5.2-147.9 18.41-175 25.9-28.9 79.82-30.8 103.83 6.1l11.6 19.5 11.6-19.5c24.11-37.1 78.12-34.8 103.83-6.1 23.71 27.3 18.4 53 18.4 175z"/></svg>
</a>
<a href="https://twitter.com/squidfunk" target="_blank" rel="noopener" title="twitter.com" class="md-social__link">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!--! Font Awesome Free 6.4.2 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2023 Fonticons, Inc.--><path d="M459.37 151.716c.325 4.548.325 9.097.325 13.645 0 138.72-105.583 298.558-298.558 298.558-59.452 0-114.68-17.219-161.137-47.106 8.447.974 16.568 1.299 25.34 1.299 49.055 0 94.213-16.568 130.274-44.832-46.132-.975-84.792-31.188-98.112-72.772 6.498.974 12.995 1.624 19.818 1.624 9.421 0 18.843-1.3 27.614-3.573-48.081-9.747-84.143-51.98-84.143-102.985v-1.299c13.969 7.797 30.214 12.67 47.431 13.319-28.264-18.843-46.781-51.005-46.781-87.391 0-19.492 5.197-37.36 14.294-52.954 51.655 63.675 129.3 105.258 216.365 109.807-1.624-7.797-2.599-15.918-2.599-24.04 0-57.828 46.782-104.934 104.934-104.934 30.213 0 57.502 12.67 76.67 33.137 23.715-4.548 46.456-13.32 66.599-25.34-7.798 24.366-24.366 44.833-46.132 57.827 21.117-2.273 41.584-8.122 60.426-16.243-14.292 20.791-32.161 39.308-52.628 54.253z"/></svg>
</a>
</div>
</div>
</div>
</footer>
</div>
<div class="md-dialog" data-md-component="dialog">
<div class="md-dialog__inner md-typeset"></div>
</div>
<script id="__config" type="application/json">{"base": "../..", "features": ["announce.dismiss", "content.action.edit", "content.action.view", "content.code.annotate", "content.code.copy", "content.tooltips", "navigation.footer", "navigation.indexes", "navigation.sections", "navigation.tabs", "navigation.top", "navigation.tracking", "search.highlight", "search.share", "search.suggest", "toc.follow"], "search": "../../assets/javascripts/workers/search.f886a092.min.js", "translations": {"clipboard.copied": "\u5df2\u590d\u5236", "clipboard.copy": "\u590d\u5236", "search.result.more.one": "\u5728\u8be5\u9875\u4e0a\u8fd8\u6709 1 \u4e2a\u7b26\u5408\u6761\u4ef6\u7684\u7ed3\u679c", "search.result.more.other": "\u5728\u8be5\u9875\u4e0a\u8fd8\u6709 # \u4e2a\u7b26\u5408\u6761\u4ef6\u7684\u7ed3\u679c", "search.result.none": "\u6ca1\u6709\u627e\u5230\u7b26\u5408\u6761\u4ef6\u7684\u7ed3\u679c", "search.result.one": "\u627e\u5230 1 \u4e2a\u7b26\u5408\u6761\u4ef6\u7684\u7ed3\u679c", "search.result.other": "# \u4e2a\u7b26\u5408\u6761\u4ef6\u7684\u7ed3\u679c", "search.result.placeholder": "\u952e\u5165\u4ee5\u5f00\u59cb\u641c\u7d22", "search.result.term.missing": "\u7f3a\u5c11", "select.version": "\u9009\u62e9\u5f53\u524d\u7248\u672c"}}</script>
<script src="../../assets/javascripts/bundle.94c44541.min.js"></script>
<script src="../../js/print-site.js"></script>
<script id="init-glightbox">const lightbox = GLightbox({"touchNavigation": true, "loop": false, "zoomable": true, "draggable": true, "openEffect": "zoom", "closeEffect": "zoom", "slideEffect": "slide"});
document$.subscribe(() => { lightbox.reload() });
</script></body>
</html>
Reference in New Issue View Git Blame Copy Permalink