hydrus/Understanding_Database_Sync...

2315 lines
59 KiB
HTML

<!doctype html>
<html lang="en" class="no-js">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<meta name="description" content="A personal booru-style media tagger that can import files and tags from your hard drive and popular websites. Content can be shared with other users via user-run servers.">
<link rel="canonical" href="https://hydrusnetwork.github.io/hydrus/Understanding_Database_Synchronization.html">
<link rel="icon" href="assets/favicon.svg">
<meta name="generator" content="mkdocs-1.5.3, mkdocs-material-9.5.15">
<title>Understanding Database Synchronization Options - hydrus network</title>
<link rel="stylesheet" href="assets/stylesheets/main.7e359304.min.css">
<link rel="stylesheet" href="assets/stylesheets/palette.06af60db.min.css">
<link rel="stylesheet" href="assets/stylesheets/extra.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>
</head>
<body dir="ltr" data-md-color-scheme="default" data-md-color-primary="blue-grey" data-md-color-accent="blue">
<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="#understanding_database_synchronization_options" class="md-skip">
Skip to content
</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="Header">
<a href="index.html" title="hydrus network" class="md-header__button md-logo" aria-label="hydrus network" data-md-component="logo">
<img src="assets/hydrus-white.svg" alt="logo">
</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">
hydrus network
</span>
</div>
<div class="md-header__topic" data-md-component="header-topic">
<span class="md-ellipsis">
Understanding Database Synchronization Options
</span>
</div>
</div>
</div>
<form class="md-header__option" data-md-component="palette">
<input class="md-option" data-md-color-media="(prefers-color-scheme: light)" data-md-color-scheme="default" data-md-color-primary="blue-grey" data-md-color-accent="blue" aria-label="Switch to dark mode" type="radio" name="__palette" id="__palette_0">
<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 6H7c-3.31 0-6 2.69-6 6s2.69 6 6 6h10c3.31 0 6-2.69 6-6s-2.69-6-6-6zm0 10H7c-2.21 0-4-1.79-4-4s1.79-4 4-4h10c2.21 0 4 1.79 4 4s-1.79 4-4 4zM7 9c-1.66 0-3 1.34-3 3s1.34 3 3 3 3-1.34 3-3-1.34-3-3-3z"/></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="blue" 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_0" 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>
</form>
<script>var media,input,key,value,palette=__md_get("__palette");if(palette&&palette.color){"(prefers-color-scheme)"===palette.color.media&&(media=matchMedia("(prefers-color-scheme: light)"),input=document.querySelector(media.matches?"[data-md-color-media='(prefers-color-scheme: light)']":"[data-md-color-media='(prefers-color-scheme: dark)']"),palette.color.media=input.getAttribute("data-md-color-media"),palette.color.scheme=input.getAttribute("data-md-color-scheme"),palette.color.primary=input.getAttribute("data-md-color-primary"),palette.color.accent=input.getAttribute("data-md-color-accent"));for([key,value]of Object.entries(palette.color))document.body.setAttribute("data-md-color-"+key,value)}</script>
<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="Search" placeholder="Search" 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="Search">
<button type="reset" class="md-search__icon md-icon" title="Clear" aria-label="Clear" 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">
Initializing search
</div>
<ol class="md-search-result__list" role="presentation"></ol>
</div>
</div>
</div>
</div>
</div>
<div class="md-header__source">
<a href="https://github.com/hydrusnetwork/hydrus" title="Go to repository" class="md-source" data-md-component="source">
<div class="md-source__icon md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 496 512"><!--! Font Awesome Free 6.5.1 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>
</div>
<div class="md-source__repository">
hydrusnetwork/hydrus
</div>
</a>
</div>
</nav>
</header>
<div class="md-container" data-md-component="container">
<nav class="md-tabs" aria-label="Tabs" data-md-component="tabs">
<div class="md-grid">
<ul class="md-tabs__list">
<li class="md-tabs__item">
<a href="index.html" class="md-tabs__link">
Home
</a>
</li>
<li class="md-tabs__item">
<a href="introduction.html" class="md-tabs__link">
Getting Started
</a>
</li>
<li class="md-tabs__item">
<a href="advanced_siblings.html" class="md-tabs__link">
Advanced
</a>
</li>
<li class="md-tabs__item">
<a href="client_api.html" class="md-tabs__link">
API
</a>
</li>
<li class="md-tabs__item">
<a href="faq.html" class="md-tabs__link">
Misc
</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="Navigation" data-md-level="0">
<label class="md-nav__title" for="__drawer">
<a href="index.html" title="hydrus network" class="md-nav__button md-logo" aria-label="hydrus network" data-md-component="logo">
<img src="assets/hydrus-white.svg" alt="logo">
</a>
hydrus network
</label>
<div class="md-nav__source">
<a href="https://github.com/hydrusnetwork/hydrus" title="Go to repository" class="md-source" data-md-component="source">
<div class="md-source__icon md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 496 512"><!--! Font Awesome Free 6.5.1 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>
</div>
<div class="md-source__repository">
hydrusnetwork/hydrus
</div>
</a>
</div>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="index.html" class="md-nav__link">
<span class="md-ellipsis">
Home
</span>
</a>
</li>
<li class="md-nav__item 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="0">
<span class="md-ellipsis">
Getting Started
</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>
Getting Started
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="introduction.html" class="md-nav__link">
<span class="md-ellipsis">
Introduction and Statement of Principles
</span>
</a>
</li>
<li class="md-nav__item">
<a href="gettingStartedOverview.html" class="md-nav__link">
<span class="md-ellipsis">
Overview For Getting Started
</span>
</a>
</li>
<li class="md-nav__item">
<a href="getting_started_installing.html" class="md-nav__link">
<span class="md-ellipsis">
Installing and Updating
</span>
</a>
</li>
<li class="md-nav__item">
<a href="getting_started_files.html" class="md-nav__link">
<span class="md-ellipsis">
Files
</span>
</a>
</li>
<li class="md-nav__item">
<a href="filetypes.html" class="md-nav__link">
<span class="md-ellipsis">
Supported Filetypes
</span>
</a>
</li>
<li class="md-nav__item">
<a href="getting_started_importing.html" class="md-nav__link">
<span class="md-ellipsis">
Importing and Exporting
</span>
</a>
</li>
<li class="md-nav__item">
<a href="getting_started_tags.html" class="md-nav__link">
<span class="md-ellipsis">
Tags
</span>
</a>
</li>
<li class="md-nav__item">
<a href="getting_started_searching.html" class="md-nav__link">
<span class="md-ellipsis">
Searching and Sorting
</span>
</a>
</li>
<li class="md-nav__item">
<a href="getting_started_more_tags.html" class="md-nav__link">
<span class="md-ellipsis">
More Tags
</span>
</a>
</li>
<li class="md-nav__item">
<a href="getting_started_downloading.html" class="md-nav__link">
<span class="md-ellipsis">
Downloading
</span>
</a>
</li>
<li class="md-nav__item">
<a href="getting_started_ratings.html" class="md-nav__link">
<span class="md-ellipsis">
Ratings
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_2_12" >
<label class="md-nav__link" for="__nav_2_12" id="__nav_2_12_label" tabindex="0">
<span class="md-ellipsis">
PTR
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="2" aria-labelledby="__nav_2_12_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_2_12">
<span class="md-nav__icon md-icon"></span>
PTR
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="access_keys.html" class="md-nav__link">
<span class="md-ellipsis">
PTR Access Keys
</span>
</a>
</li>
<li class="md-nav__item">
<a href="PTR.html" class="md-nav__link">
<span class="md-ellipsis">
PTR Guide
</span>
</a>
</li>
<li class="md-nav__item">
<a href="petitionPractices.html" class="md-nav__link">
<span class="md-ellipsis">
Petition Practices
</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_2_13" >
<label class="md-nav__link" for="__nav_2_13" id="__nav_2_13_label" tabindex="0">
<span class="md-ellipsis">
Next Steps
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="2" aria-labelledby="__nav_2_13_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_2_13">
<span class="md-nav__icon md-icon"></span>
Next Steps
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="adding_new_downloaders.html" class="md-nav__link">
<span class="md-ellipsis">
Adding New Downloaders
</span>
</a>
</li>
<li class="md-nav__item">
<a href="getting_started_subscriptions.html" class="md-nav__link">
<span class="md-ellipsis">
Subscriptions
</span>
</a>
</li>
<li class="md-nav__item">
<a href="duplicates.html" class="md-nav__link">
<span class="md-ellipsis">
Filtering Duplicates
</span>
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_3" >
<label class="md-nav__link" for="__nav_3" id="__nav_3_label" tabindex="0">
<span class="md-ellipsis">
Advanced
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<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>
Advanced
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="advanced_siblings.html" class="md-nav__link">
<span class="md-ellipsis">
Tag Siblings
</span>
</a>
</li>
<li class="md-nav__item">
<a href="advanced_parents.html" class="md-nav__link">
<span class="md-ellipsis">
Tag Parents
</span>
</a>
</li>
<li class="md-nav__item">
<a href="advanced_sidecars.html" class="md-nav__link">
<span class="md-ellipsis">
Sidecars
</span>
</a>
</li>
<li class="md-nav__item">
<a href="advanced_multiple_local_file_services.html" class="md-nav__link">
<span class="md-ellipsis">
Multiple Local File Services
</span>
</a>
</li>
<li class="md-nav__item">
<a href="advanced.html" class="md-nav__link">
<span class="md-ellipsis">
General Clever Tricks
</span>
</a>
</li>
<li class="md-nav__item">
<a href="reducing_lag.html" class="md-nav__link">
<span class="md-ellipsis">
Reducing Lag
</span>
</a>
</li>
<li class="md-nav__item">
<a href="database_migration.html" class="md-nav__link">
<span class="md-ellipsis">
Database Migration
</span>
</a>
</li>
<li class="md-nav__item">
<a href="launch_arguments.html" class="md-nav__link">
<span class="md-ellipsis">
Launch Arguments
</span>
</a>
</li>
<li class="md-nav__item">
<a href="ipfs.html" class="md-nav__link">
<span class="md-ellipsis">
IPFS
</span>
</a>
</li>
<li class="md-nav__item">
<a href="local_booru.html" class="md-nav__link">
<span class="md-ellipsis">
Local Booru
</span>
</a>
</li>
<li class="md-nav__item">
<a href="server.html" class="md-nav__link">
<span class="md-ellipsis">
Running Your Own Server
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_3_12" >
<label class="md-nav__link" for="__nav_3_12" id="__nav_3_12_label" tabindex="0">
<span class="md-ellipsis">
Alternate Installations
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="2" aria-labelledby="__nav_3_12_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_3_12">
<span class="md-nav__icon md-icon"></span>
Alternate Installations
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="docker.html" class="md-nav__link">
<span class="md-ellipsis">
Docker
</span>
</a>
</li>
<li class="md-nav__item">
<a href="wine.html" class="md-nav__link">
<span class="md-ellipsis">
Running In Wine
</span>
</a>
</li>
<li class="md-nav__item">
<a href="running_from_source.html" class="md-nav__link">
<span class="md-ellipsis">
Running From Source
</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_3_13" >
<label class="md-nav__link" for="__nav_3_13" id="__nav_3_13_label" tabindex="0">
<span class="md-ellipsis">
Downloader Creation
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="2" aria-labelledby="__nav_3_13_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_3_13">
<span class="md-nav__icon md-icon"></span>
Downloader Creation
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="downloader_intro.html" class="md-nav__link">
<span class="md-ellipsis">
Introduction
</span>
</a>
</li>
<li class="md-nav__item">
<a href="downloader_gugs.html" class="md-nav__link">
<span class="md-ellipsis">
Gallery URL Generators
</span>
</a>
</li>
<li class="md-nav__item">
<a href="downloader_url_classes.html" class="md-nav__link">
<span class="md-ellipsis">
URL Classes
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_3_13_4" >
<label class="md-nav__link" for="__nav_3_13_4" id="__nav_3_13_4_label" tabindex="0">
<span class="md-ellipsis">
Parsers
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="3" aria-labelledby="__nav_3_13_4_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_3_13_4">
<span class="md-nav__icon md-icon"></span>
Parsers
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="downloader_parsers.html" class="md-nav__link">
<span class="md-ellipsis">
Overview
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_3_13_4_2" >
<label class="md-nav__link" for="__nav_3_13_4_2" id="__nav_3_13_4_2_label" tabindex="0">
<span class="md-ellipsis">
Components
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="4" aria-labelledby="__nav_3_13_4_2_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_3_13_4_2">
<span class="md-nav__icon md-icon"></span>
Components
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="downloader_parsers_formulae.html" class="md-nav__link">
<span class="md-ellipsis">
Formulae
</span>
</a>
</li>
<li class="md-nav__item">
<a href="downloader_parsers_content_parsers.html" class="md-nav__link">
<span class="md-ellipsis">
Content Parsers
</span>
</a>
</li>
<li class="md-nav__item">
<a href="downloader_parsers_page_parsers.html" class="md-nav__link">
<span class="md-ellipsis">
Page Parsers
</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_3_13_4_3" >
<label class="md-nav__link" for="__nav_3_13_4_3" id="__nav_3_13_4_3_label" tabindex="0">
<span class="md-ellipsis">
Walkthroughs
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="4" aria-labelledby="__nav_3_13_4_3_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_3_13_4_3">
<span class="md-nav__icon md-icon"></span>
Walkthroughs
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="downloader_parsers_full_example_gallery_page.html" class="md-nav__link">
<span class="md-ellipsis">
Gallery Page Example
</span>
</a>
</li>
<li class="md-nav__item">
<a href="downloader_parsers_full_example_file_page.html" class="md-nav__link">
<span class="md-ellipsis">
File Page Example
</span>
</a>
</li>
<li class="md-nav__item">
<a href="downloader_parsers_full_example_api.html" class="md-nav__link">
<span class="md-ellipsis">
API Example
</span>
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="downloader_completion.html" class="md-nav__link">
<span class="md-ellipsis">
Putting It All Together
</span>
</a>
</li>
<li class="md-nav__item">
<a href="downloader_sharing.html" class="md-nav__link">
<span class="md-ellipsis">
Sharing
</span>
</a>
</li>
<li class="md-nav__item">
<a href="downloader_login.html" class="md-nav__link">
<span class="md-ellipsis">
Login Manager
</span>
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item 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="0">
<span class="md-ellipsis">
API
</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>
API
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="client_api.html" class="md-nav__link">
<span class="md-ellipsis">
Client API
</span>
</a>
</li>
<li class="md-nav__item">
<a href="developer_api.html" class="md-nav__link">
<span class="md-ellipsis">
API documentation
</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_5" >
<label class="md-nav__link" for="__nav_5" id="__nav_5_label" tabindex="0">
<span class="md-ellipsis">
Misc
</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>
Misc
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="faq.html" class="md-nav__link">
<span class="md-ellipsis">
FAQ
</span>
</a>
</li>
<li class="md-nav__item">
<a href="privacy.html" class="md-nav__link">
<span class="md-ellipsis">
Privacy
</span>
</a>
</li>
<li class="md-nav__item">
<a href="contact.html" class="md-nav__link">
<span class="md-ellipsis">
Contact and Links
</span>
</a>
</li>
<li class="md-nav__item">
<a href="support.html" class="md-nav__link">
<span class="md-ellipsis">
Financial Support
</span>
</a>
</li>
<li class="md-nav__item">
<a href="changelog.html" class="md-nav__link">
<span class="md-ellipsis">
Changelog
</span>
</a>
</li>
<li class="md-nav__item">
<a href="about_docs.html" class="md-nav__link">
<span class="md-ellipsis">
About These Docs
</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="Table of contents">
<label class="md-nav__title" for="__toc">
<span class="md-nav__icon md-icon"></span>
Table of contents
</label>
<ul class="md-nav__list" data-md-component="toc" data-md-scrollfix>
<li class="md-nav__item">
<a href="#key_points" class="md-nav__link">
<span class="md-ellipsis">
Key Points
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#the_secret_sauce" class="md-nav__link">
<span class="md-ellipsis">
The Secret Sauce
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#technical_explanation" class="md-nav__link">
<span class="md-ellipsis">
Technical Explanation
</span>
</a>
<nav class="md-nav" aria-label="Technical Explanation">
<ul class="md-nav__list">
<li class="md-nav__item">
<a href="#an_example_journal" class="md-nav__link">
<span class="md-ellipsis">
An example journal
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#where_synchronization_comes_in" class="md-nav__link">
<span class="md-ellipsis">
Where synchronization comes in
</span>
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</div>
</div>
</div>
<div class="md-content" data-md-component="content">
<article class="md-content__inner md-typeset">
<a href="https://github.com/hydrusnetwork/hydrus/edit/master/docs/Understanding_Database_Synchronization.md" title="Edit this page" class="md-content__button md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M10 20H6V4h7v5h5v3.1l2-2V8l-6-6H6c-1.1 0-2 .9-2 2v16c0 1.1.9 2 2 2h4v-2m10.2-7c.1 0 .3.1.4.2l1.3 1.3c.2.2.2.6 0 .8l-1 1-2.1-2.1 1-1c.1-.1.2-.2.4-.2m0 3.9L14.1 23H12v-2.1l6.1-6.1 2.1 2.1Z"/></svg>
</a>
<h1 id="understanding_database_synchronization_options">Understanding Database Synchronization Options<a class="headerlink" href="#understanding_database_synchronization_options" title="Permanent link">&para;</a></h1>
<p>Tuning your database synchronization using the <code>--db_synchronous_override=0</code> launch argument can make Hydrus significantly faster with some caveats.</p>
<h2 id="key_points">Key Points<a class="headerlink" href="#key_points" title="Permanent link">&para;</a></h2>
<ul>
<li>This is a tutorial for advanced users who have read and understood this document and the risk/recovery procedure.</li>
<li>It is nearly always safe to use <code>--db_synchronous_override=1</code> on any modern filesystem and this is the default.</li>
<li>It is always more expensive to access the disk than doing things in memory. SSDs are 10-100x as slow as memory, and HDDs are 1000-10000x as slow as memory.</li>
<li>If you turn synchronization to <code>0</code> you are gambling, but it is a safe gamble if you have a backup and <strong>know exactly</strong> what you are doing</li>
<li>After running with synchronization set to zero you must either:</li>
<li>Exit hydrus normally and let the OS flush disk caches (either by letting the system run/"idle" for a while, running <code>sync</code> on *NIX systems, or normal shutdown), or</li>
<li>Restore the sqlite database files backup if <strong>the OS shutdown abnormally</strong>.</li>
<li>Because of the potential for a lot of outstanding writes when using <code>synchronous=0</code>, other I/O on your system will slow down as the pending writes are interleaved. Normal shutdown may also take abnormally long because the system is flushing these pending writes, but you must allow it to take its time as explained in the section below.</li>
</ul>
<p><strong>Note:</strong> In historical versions of hydrus (<code>synchronous=2</code>), performance was terrible because hydrus would agressively (it was arguably somewhat paranoid) write changes to disk.</p>
<h2 id="the_secret_sauce">The Secret Sauce<a class="headerlink" href="#the_secret_sauce" title="Permanent link">&para;</a></h2>
<p>Setting the synchronous to 0 lets the database engine defer writing to disk as long as physically possible. In the normal operation of your system, files are constantly being partially transfered to disk, even if the OS pretends they have been fully written to disk. This is called write cache and it is really important to use it or your system's performance would be terrible. The caveat is that until you have "<code>synced</code>" the disk cache, the changes to files are not actually in permanent storage. One purpose of a normal shutdown of the operating system is to make sure all disk caches have been flushed and synced. A program can also request that a file it has just written to be flushed or synced, and it will wait until that is done before continuing.</p>
<p>When not in synchronous 0 mode, the database engine syncs at regular intervals to make sure data has been written.<br />
- Setting synchronous to 0 is generally safe <strong>if and only if</strong> the system also shuts down normally, allowing any of these pending writes to be flushed.
- The database can back out of partial changes if hydrus crashes <strong>even if</strong> <code>synchronous=0</code>, so your database will not go corrupt from hydrus shutting down abnormally, only from the system shutting down abnormally.</p>
<h2 id="technical_explanation">Technical Explanation<a class="headerlink" href="#technical_explanation" title="Permanent link">&para;</a></h2>
<p>Programmers are responsible for handling partially written files, but this is tedious for large complex data, so they use a database engine which handles all of this. The database ensures that any partially written data is reversible to a known state (called a rollback).</p>
<p>An existing file may be in 3 possible states:</p>
<ul>
<li><strong>Unflushed</strong>: Contents is owned by the program writing the file, but control returns immediately to the program instead of waiting for a full write. Content can be transitioned from unflushed to flushed using <code>fflush(FILE)</code>. <code>fflush()</code> is called automatically when a programmer closes a file, or exits the program normally(under most runtimes but not for example in Java). If the program exits abnormally before data is flushed it will be lost when the program crashes.</li>
<li><strong>Flushed</strong>: Pending write to permenant storage but memory has been transfered to the operating system. Data will not be lost if the calling program crashes, since the OS promises it will "eventually" arrive on disk before returning from <code>fflush()</code>. When you "safely shutdown:, you are instructing the OS among other things to sync the flushed files. If someone decides to read a file before it has been synced the OS will read the contents up until the flush from the flush buffer, and return that instead of what is actually on disk. If the OS crashes due to error or power failure, data that are flushed but not synced will be lost.</li>
<li><strong>Synced</strong>: Written to permenant storage. A programmer may request that the contents of the file be synced, or it is done gradually over time to free the OS buffers</li>
</ul>
<p>To ensure the consistency of the database and rollback when needed, the database engine keeps a <strong>journal</strong> of what it is doing. Each transaction ends in a <code>flush</code> followed by a <code>sync</code>. The <em>flush</em> ensures that everything written before the flush will occur before the line that indicats the transaction completed. The <em>sync</em> ensures that the entire contents of the transaction has been written to permenant storage before proceeding. The OS is not obligated to write chunks of the database file in the order it recieves them. It only guarantees that if you flush everything before the flush happens first, and everything after happens next.</p>
<p>The sync is what is controlled by the <code>synchronous</code> switch. Allowing the database to ignore whether sync actually completes is the magic that makes <code>synchronous=0</code> so dang fast.</p>
<h3 id="an_example_journal">An example journal<a class="headerlink" href="#an_example_journal" title="Permanent link">&para;</a></h3>
<ol>
<li>Begin Transaction 1</li>
<li>Write Change 1</li>
<li>Write Change 2</li>
<li>Read data</li>
<li>Write Change 3</li>
<li>End Transaction 1</li>
</ol>
<p>Each of these steps are performed in order. Suppose a crash occcured mid writing</p>
<ol>
<li>Begin Transaction 1</li>
<li>Write Change 1</li>
<li>Write Cha</li>
</ol>
<p>When the database resumes it will start scanning the journal at step 1. Since it will reach the end without seeing <code>End Transaction 1</code> it knows that data was only partialy written, and can put the data back in the state before transaction 1 began. This property of a database is called <strong>atomicity</strong> in the sense that something <strong>atomic</strong> is "indivisible"; either all of the steps in transaction 1 occur or non of them occur.</p>
<p>Hydrus is structured in such a way that the database is written to to keep track of your file catalog only once the file has been fully imported and moved where it is supposed to be. Thus every action hydrus takes is kept "atomic" or "repeatable" (redo existing work that was partway through). If hydrus crashes in the middle of importing a file, then when it resumes, as far as it is aware, it didn't even start importing the file. It will repeat the steps from the start until the file catalog is "consistent" with what is on disk.</p>
<h3 id="where_synchronization_comes_in">Where synchronization comes in<a class="headerlink" href="#where_synchronization_comes_in" title="Permanent link">&para;</a></h3>
<p>Lets revisit the journal, this time with two transactions. Note that the database is syncing on step 8 and thus will have to wait for the OS to write to disk before proceeding, holding up transaction 2, and any other access to the database.</p>
<ol>
<li>Begin Transaction 1</li>
<li>Write Change 1</li>
<li>Write Change 2</li>
<li>Read data</li>
<li>Write Change 3</li>
<li>FLUSH</li>
<li>End Transaction 1</li>
<li>SYNC</li>
<li>Begin Transaction 2</li>
<li>Write Change 2</li>
<li>Write Change 2</li>
<li>Read data</li>
<li>Write Change 3</li>
<li>FLUSH</li>
<li>End Transaction 2</li>
<li>SYNC</li>
</ol>
<p><strong>What happens if we remove step 6 and 8 and then die at step 11?</strong></p>
<ol>
<li>Begin Transaction 1</li>
<li>Write Change 1</li>
<li>Write Change 2</li>
<li>Read data</li>
<li>Write Change 3</li>
<li><del>FLUSH</del></li>
<li>End Transaction 1</li>
<li><del>SYNC</del></li>
<li>Begin Transaction 2</li>
<li>Write Change 2</li>
<li>Write Ch</li>
</ol>
<p>What if we crash and step, <code>End Transaction</code> has not been written to disk. Now not only do we need to repeat transaction 2, we also need to repeat transaction 1. Note that <strong>this just increaeses the ammount of repeatable work, and actually is fully recoverable</strong> (assuming a file you were downloading didn't cease to exist in the interim).</p>
<p><strong>Now what happens if we do the above and the OS crashes?</strong>
The OS is not obligated to write chunks of the database file in the order you give them to it, in fact for harddrives it is optimal to scatter chunks of the file around the spinning disks so it might arbitrarily reorder your write calls. </p>
<ul>
<li>The only way you can be certain that all of the changes in the transaction have been written before writing <code>END Transaction</code> is to <code>flush()</code></li>
<li>The only way you can be sure <code>END Transaction</code> was written before doing more changes is to <code>sync()</code>.</li>
</ul>
<p>Thus if the OS crashes at the exact wrong moment, there is no way to be sure that the journal is correct if flushing was skipped (<code>synchronous=0</code>). <strong>This means there is no way for you to determine whether the database file is correct after a system crash if you had synchronous 0, and you MUST restore your files from backup as this will be the ONLY WAY to know they are in a known good state.</strong></p>
<p>So, setting <code>synchronous=0</code> gets you a pretty huge speed boost, but you are gambling that everything goes perfectly and will pay the price of a manual restore every time it doesn't.</p>
<aside class="md-source-file">
<span class="md-source-file__fact">
<span class="md-icon" title="Last update">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M21 13.1c-.1 0-.3.1-.4.2l-1 1 2.1 2.1 1-1c.2-.2.2-.6 0-.8l-1.3-1.3c-.1-.1-.2-.2-.4-.2m-1.9 1.8-6.1 6V23h2.1l6.1-6.1-2.1-2M12.5 7v5.2l4 2.4-1 1L11 13V7h1.5M11 21.9c-5.1-.5-9-4.8-9-9.9C2 6.5 6.5 2 12 2c5.3 0 9.6 4.1 10 9.3-.3-.1-.6-.2-1-.2s-.7.1-1 .2C19.6 7.2 16.2 4 12 4c-4.4 0-8 3.6-8 8 0 4.1 3.1 7.5 7.1 7.9l-.1.2v1.8Z"/></svg>
</span>
<span class="git-revision-date-localized-plugin git-revision-date-localized-plugin-date">March 13, 2022</span>
</span>
</aside>
</article>
</div>
<script>var tabs=__md_get("__tabs");if(Array.isArray(tabs))e:for(var set of document.querySelectorAll(".tabbed-set")){var tab,labels=set.querySelector(".tabbed-labels");for(tab of tabs)for(var label of labels.getElementsByTagName("label"))if(label.innerText.trim()===tab){var input=document.getElementById(label.htmlFor);input.checked=!0;continue e}}</script>
<script>var target=document.getElementById(location.hash.slice(1));target&&target.name&&(target.checked=target.name.startsWith("__tabbed_"))</script>
</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>
Back to top
</button>
</main>
<footer class="md-footer">
<div class="md-footer-meta md-typeset">
<div class="md-footer-meta__inner md-grid">
<div class="md-copyright">
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/hydrusnetwork/hydrus" 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 6.5.1 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://twitter.com/hydrusnetwork" 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 6.5.1 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>
<a href="https://hydrus.tumblr.com/" target="_blank" rel="noopener" title="hydrus.tumblr.com" class="md-social__link">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!--! Font Awesome Free 6.5.1 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="M309.8 480.3c-13.6 14.5-50 31.7-97.4 31.7-120.8 0-147-88.8-147-140.6v-144H17.9c-5.5 0-10-4.5-10-10v-68c0-7.2 4.5-13.6 11.3-16 62-21.8 81.5-76 84.3-117.1.8-11 6.5-16.3 16.1-16.3h70.9c5.5 0 10 4.5 10 10v115.2h83c5.5 0 10 4.4 10 9.9v81.7c0 5.5-4.5 10-10 10h-83.4V360c0 34.2 23.7 53.6 68 35.8 4.8-1.9 9-3.2 12.7-2.2 3.5.9 5.8 3.4 7.4 7.9l22 64.3c1.8 5 3.3 10.6-.4 14.5z"/></svg>
</a>
<a href="mailto:hydrus.admin@gmail.com" target="_blank" rel="noopener" title="" class="md-social__link">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!--! Font Awesome Free 6.5.1 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="M48 64C21.5 64 0 85.5 0 112c0 15.1 7.1 29.3 19.2 38.4l217.6 163.2c11.4 8.5 27 8.5 38.4 0l217.6-163.2c12.1-9.1 19.2-23.3 19.2-38.4 0-26.5-21.5-48-48-48H48zM0 176v208c0 35.3 28.7 64 64 64h384c35.3 0 64-28.7 64-64V176L294.4 339.2a63.9 63.9 0 0 1-76.8 0L0 176z"/></svg>
</a>
<a href="https://discord.gg/wPHPCUZ" target="_blank" rel="noopener" title="discord.gg" class="md-social__link">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 640 512"><!--! Font Awesome Free 6.5.1 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="M524.531 69.836a1.5 1.5 0 0 0-.764-.7A485.065 485.065 0 0 0 404.081 32.03a1.816 1.816 0 0 0-1.923.91 337.461 337.461 0 0 0-14.9 30.6 447.848 447.848 0 0 0-134.426 0 309.541 309.541 0 0 0-15.135-30.6 1.89 1.89 0 0 0-1.924-.91 483.689 483.689 0 0 0-119.688 37.107 1.712 1.712 0 0 0-.788.676C39.068 183.651 18.186 294.69 28.43 404.354a2.016 2.016 0 0 0 .765 1.375 487.666 487.666 0 0 0 146.825 74.189 1.9 1.9 0 0 0 2.063-.676A348.2 348.2 0 0 0 208.12 430.4a1.86 1.86 0 0 0-1.019-2.588 321.173 321.173 0 0 1-45.868-21.853 1.885 1.885 0 0 1-.185-3.126 251.047 251.047 0 0 0 9.109-7.137 1.819 1.819 0 0 1 1.9-.256c96.229 43.917 200.41 43.917 295.5 0a1.812 1.812 0 0 1 1.924.233 234.533 234.533 0 0 0 9.132 7.16 1.884 1.884 0 0 1-.162 3.126 301.407 301.407 0 0 1-45.89 21.83 1.875 1.875 0 0 0-1 2.611 391.055 391.055 0 0 0 30.014 48.815 1.864 1.864 0 0 0 2.063.7A486.048 486.048 0 0 0 610.7 405.729a1.882 1.882 0 0 0 .765-1.352c12.264-126.783-20.532-236.912-86.934-334.541ZM222.491 337.58c-28.972 0-52.844-26.587-52.844-59.239s23.409-59.241 52.844-59.241c29.665 0 53.306 26.82 52.843 59.239 0 32.654-23.41 59.241-52.843 59.241Zm195.38 0c-28.971 0-52.843-26.587-52.843-59.239s23.409-59.241 52.843-59.241c29.667 0 53.307 26.82 52.844 59.239 0 32.654-23.177 59.241-52.844 59.241Z"/></svg>
</a>
<a href="https://www.patreon.com/hydrus_dev" target="_blank" rel="noopener" title="www.patreon.com" class="md-social__link">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!--! Font Awesome Free 6.5.1 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="M489.7 153.8c-.1-65.4-51-119-110.7-138.3C304.8-8.5 207-5 136.1 28.4 50.3 68.9 23.3 157.7 22.3 246.2 21.5 319 28.7 510.6 136.9 512c80.3 1 92.3-102.5 129.5-152.3 26.4-35.5 60.5-45.5 102.4-55.9 72-17.8 121.1-74.7 121-150z"/></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": ["navigation.tracking", "navigation.sections", "navigation.tabs", "content.tabs.link", "navigation.top", "search.suggest", "content.code.annotate", "navigation.instant", "content.action.edit"], "search": "assets/javascripts/workers/search.b8dbb3d2.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}}</script>
<script src="assets/javascripts/bundle.bd41221c.min.js"></script>
</body>
</html>