2022-02-01 14:04:50 +03:00
<!DOCTYPE HTML>
< html lang = "en" class = "sidebar-visible no-js light" >
< head >
<!-- Book generated using mdBook -->
< meta charset = "UTF-8" >
< title > Replication - Synapse< / title >
<!-- Custom HTML head -->
< meta content = "text/html; charset=utf-8" http-equiv = "Content-Type" >
< meta name = "description" content = "" >
< meta name = "viewport" content = "width=device-width, initial-scale=1" >
< meta name = "theme-color" content = "#ffffff" / >
< link rel = "icon" href = "favicon.svg" >
< link rel = "shortcut icon" href = "favicon.png" >
< link rel = "stylesheet" href = "css/variables.css" >
< link rel = "stylesheet" href = "css/general.css" >
< link rel = "stylesheet" href = "css/chrome.css" >
< link rel = "stylesheet" href = "css/print.css" media = "print" >
<!-- Fonts -->
< link rel = "stylesheet" href = "FontAwesome/css/font-awesome.css" >
< link rel = "stylesheet" href = "fonts/fonts.css" >
<!-- Highlight.js Stylesheets -->
< link rel = "stylesheet" href = "highlight.css" >
< link rel = "stylesheet" href = "tomorrow-night.css" >
< link rel = "stylesheet" href = "ayu-highlight.css" >
<!-- Custom theme stylesheets -->
< link rel = "stylesheet" href = "docs/website_files/table-of-contents.css" >
< link rel = "stylesheet" href = "docs/website_files/remove-nav-buttons.css" >
< link rel = "stylesheet" href = "docs/website_files/indent-section-headers.css" >
2023-12-11 17:57:10 +03:00
< link rel = "stylesheet" href = "docs/website_files/version-picker.css" >
2022-02-01 14:04:50 +03:00
< / head >
< body >
<!-- Provide site root to javascript -->
< script type = "text/javascript" >
var path_to_root = "";
var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "navy" : "light";
< / script >
<!-- Work around some values being stored in localStorage wrapped in quotes -->
< script type = "text/javascript" >
try {
var theme = localStorage.getItem('mdbook-theme');
var sidebar = localStorage.getItem('mdbook-sidebar');
if (theme.startsWith('"') & & theme.endsWith('"')) {
localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
}
if (sidebar.startsWith('"') & & sidebar.endsWith('"')) {
localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
}
} catch (e) { }
< / script >
<!-- Set the theme before any content is loaded, prevents flash -->
< script type = "text/javascript" >
var theme;
try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
if (theme === null || theme === undefined) { theme = default_theme; }
var html = document.querySelector('html');
html.classList.remove('no-js')
html.classList.remove('light')
html.classList.add(theme);
html.classList.add('js');
< / script >
<!-- Hide / unhide sidebar before it is displayed -->
< script type = "text/javascript" >
var html = document.querySelector('html');
var sidebar = 'hidden';
if (document.body.clientWidth >= 1080) {
try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
sidebar = sidebar || 'visible';
}
html.classList.remove('sidebar-visible');
html.classList.add("sidebar-" + sidebar);
< / script >
< nav id = "sidebar" class = "sidebar" aria-label = "Table of contents" >
< div class = "sidebar-scrollbox" >
< ol class = "chapter" > < li class = "chapter-item expanded affix " > < li class = "part-title" > Introduction< / li > < li class = "chapter-item expanded " > < a href = "welcome_and_overview.html" > Welcome and Overview< / a > < / li > < li class = "chapter-item expanded affix " > < li class = "part-title" > Setup< / li > < li class = "chapter-item expanded " > < a href = "setup/installation.html" > Installation< / a > < / li > < li class = "chapter-item expanded " > < a href = "postgres.html" > Using Postgres< / a > < / li > < li class = "chapter-item expanded " > < a href = "reverse_proxy.html" > Configuring a Reverse Proxy< / a > < / li > < li class = "chapter-item expanded " > < a href = "setup/forward_proxy.html" > Configuring a Forward/Outbound Proxy< / a > < / li > < li class = "chapter-item expanded " > < a href = "turn-howto.html" > Configuring a Turn Server< / a > < / li > < li class = "chapter-item expanded " > < a href = "delegate.html" > Delegation< / a > < / li > < li class = "chapter-item expanded affix " > < li class = "part-title" > Upgrading< / li > < li class = "chapter-item expanded " > < a href = "upgrade.html" > Upgrading between Synapse Versions< / a > < / li > < li class = "chapter-item expanded " > < a href = "MSC1711_certificates_FAQ.html" > Upgrading from pre-Synapse 1.0< / a > < / li > < li class = "chapter-item expanded affix " > < li class = "part-title" > Usage< / li > < li class = "chapter-item expanded " > < a href = "federate.html" > Federation< / a > < / li > < li class = "chapter-item expanded " > < a href = "usage/configuration/index.html" > Configuration< / a > < / li > < li > < ol class = "section" > < li class = "chapter-item expanded " > < a href = "usage/configuration/homeserver_sample_config.html" > Homeserver Sample Config File< / a > < / li > < li class = "chapter-item expanded " > < a href = "usage/configuration/logging_sample_config.html" > Logging Sample Config File< / a > < / li > < li class = "chapter-item expanded " > < a href = "structured_logging.html" > Structured Logging< / a > < / li > < li class = "chapter-item expanded " > < a href = "templates.html" > Templates< / a > < / li > < li class = "chapter-item expanded " > < a href = "usage/configuration/user_authentication/index.html" > User Authentication< / a > < / li > < li > < ol class = "section" > < li class = "chapter-item expanded " > < a href = "usage/configuration/user_authentication/single_sign_on/index.html" > Single-Sign On< / a > < / li > < li > < ol class = "section" > < li class = "chapter-item expanded " > < a href = "openid.html" > OpenID Connect< / a > < / li > < li class = "chapter-item expanded " > < a href = "usage/configuration/user_authentication/single_sign_on/saml.html" > SAML< / a > < / li > < li class = "chapter-item expanded " > < a href = "usage/configuration/user_authentication/single_sign_on/cas.html" > CAS< / a > < / li > < li class = "chapter-item expanded " > < a href = "sso_mapping_providers.html" > SSO Mapping Providers< / a > < / li > < / ol > < / li > < li class = "chapter-item expanded " > < a href = "password_auth_providers.html" > Password Auth Providers< / a > < / li > < li class = "chapter-item expanded " > < a href = "jwt.html" > JSON Web Tokens< / a > < / li > < li class = "chapter-item expanded " > < a href = "usage/configuration/user_authentication/refresh_tokens.html" > Refresh Tokens< / a > < / li > < / ol > < / li > < li class = "chapter-item expanded " > < a href = "CAPTCHA_SETUP.html" > Registration Captcha< / a > < / li > < li class = "chapter-item expanded " > < a href = "application_services.html" > Application Services< / a > < / li > < li class = "chapter-item expanded " > < a href = "server_notices.html" > Server Notices< / a > < / li > < li class = "chapter-item expanded " > < a href = "consent_tracking.html" > Consent Tracking< / a > < / li > < li class = "chapter-item expanded " > < a href = "development/url_previews.html" > URL Previews< / a > < / li > < li class = "chapter-item expanded " > < a href = "user_directory.html" > User Directory< / a > < / li > < li class = "chapter-item expanded " > < a href = "message_retention_policies.html" > Message Retention Policies< / a > < / li > < li class = "chapter-item expanded " > < a href = "modules/index.html" > Pluggable Modules< / a > < / li > < li > < ol class = "section" > < li class = "chapter-item expanded " > < a href = "modules/writing_a_module.html" > Writing a module< / a > < / li > < li > < ol class = "section" > < li class = "chapter-item expanded " > < a href = "modules/spam_checker_callbacks.html" > Spam checker callbacks< / a > < / li > < li class = "chapter-item expanded " > < a href = "modules/third_party_rules_callbacks.html" > Third-party rules callbacks< / a > < / li > < li class = "chapter-item expanded " > < a
< / div >
< div id = "sidebar-resize-handle" class = "sidebar-resize-handle" > < / div >
< / nav >
< div id = "page-wrapper" class = "page-wrapper" >
< div class = "page" >
< div id = "menu-bar-hover-placeholder" > < / div >
< div id = "menu-bar" class = "menu-bar sticky bordered" >
< div class = "left-buttons" >
< button id = "sidebar-toggle" class = "icon-button" type = "button" title = "Toggle Table of Contents" aria-label = "Toggle Table of Contents" aria-controls = "sidebar" >
< i class = "fa fa-bars" > < / i >
< / button >
< button id = "theme-toggle" class = "icon-button" type = "button" title = "Change theme" aria-label = "Change theme" aria-haspopup = "true" aria-expanded = "false" aria-controls = "theme-list" >
< i class = "fa fa-paint-brush" > < / i >
< / button >
< ul id = "theme-list" class = "theme-popup" aria-label = "Themes" role = "menu" >
< li role = "none" > < button role = "menuitem" class = "theme" id = "light" > Light (default)< / button > < / li >
< li role = "none" > < button role = "menuitem" class = "theme" id = "rust" > Rust< / button > < / li >
< li role = "none" > < button role = "menuitem" class = "theme" id = "coal" > Coal< / button > < / li >
< li role = "none" > < button role = "menuitem" class = "theme" id = "navy" > Navy< / button > < / li >
< li role = "none" > < button role = "menuitem" class = "theme" id = "ayu" > Ayu< / button > < / li >
< / ul >
< button id = "search-toggle" class = "icon-button" type = "button" title = "Search. (Shortkey: s)" aria-label = "Toggle Searchbar" aria-expanded = "false" aria-keyshortcuts = "S" aria-controls = "searchbar" >
< i class = "fa fa-search" > < / i >
< / button >
2023-12-11 17:57:10 +03:00
< div class = "version-picker" >
< div class = "dropdown" >
< div class = "select" >
< span > < / span >
< i class = "fa fa-chevron-down" > < / i >
< / div >
< input type = "hidden" name = "version" >
< ul class = "dropdown-menu" >
<!-- Versions will be added dynamically in version - picker.js -->
< / ul >
< / div >
< / div >
2022-02-01 14:04:50 +03:00
< / div >
< h1 class = "menu-title" > Synapse< / h1 >
< div class = "right-buttons" >
< a href = "print.html" title = "Print this book" aria-label = "Print this book" >
< i id = "print-button" class = "fa fa-print" > < / i >
< / a >
< a href = "https://github.com/matrix-org/synapse" title = "Git repository" aria-label = "Git repository" >
< i id = "git-repository-button" class = "fa fa-github" > < / i >
< / a >
< a href = "https://github.com/matrix-org/synapse/edit/develop/docs/replication.md" title = "Suggest an edit" aria-label = "Suggest an edit" >
< i id = "git-edit-button" class = "fa fa-edit" > < / i >
< / a >
< / div >
< / div >
< div id = "search-wrapper" class = "hidden" >
< form id = "searchbar-outer" class = "searchbar-outer" >
< input type = "search" id = "searchbar" name = "searchbar" placeholder = "Search this book ..." aria-controls = "searchresults-outer" aria-describedby = "searchresults-header" >
< / form >
< div id = "searchresults-outer" class = "searchresults-outer hidden" >
< div id = "searchresults-header" class = "searchresults-header" > < / div >
< ul id = "searchresults" >
< / ul >
< / div >
< / div >
<!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
< script type = "text/javascript" >
document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
});
< / script >
< div id = "content" class = "content" >
< main >
<!-- Page table of contents -->
< div class = "sidetoc" >
< nav class = "pagetoc" > < / nav >
< / div >
< h1 id = "replication-architecture" > < a class = "header" href = "#replication-architecture" > Replication Architecture< / a > < / h1 >
< h2 id = "motivation" > < a class = "header" href = "#motivation" > Motivation< / a > < / h2 >
< p > We'd like to be able to split some of the work that synapse does into
multiple python processes. In theory multiple synapse processes could
share a single postgresql database and we'd scale up by running more
synapse processes. However much of synapse assumes that only one process
is interacting with the database, both for assigning unique identifiers
when inserting into tables, notifying components about new updates, and
for invalidating its caches.< / p >
< p > So running multiple copies of the current code isn't an option. One way
to run multiple processes would be to have a single writer process and
multiple reader processes connected to the same database. In order to do
this we'd need a way for the reader process to invalidate its in-memory
caches when an update happens on the writer. One way to do this is for
the writer to present an append-only log of updates which the readers
can consume to invalidate their caches and to push updates to listening
clients or pushers.< / p >
< p > Synapse already stores much of its data as an append-only log so that it
can correctly respond to < code > /sync< / code > requests so the amount of code changes
needed to expose the append-only log to the readers should be fairly
minimal.< / p >
< h2 id = "architecture" > < a class = "header" href = "#architecture" > Architecture< / a > < / h2 >
< h3 id = "the-replication-protocol" > < a class = "header" href = "#the-replication-protocol" > The Replication Protocol< / a > < / h3 >
< p > See < a href = "tcp_replication.html" > the TCP replication documentation< / a > .< / p >
< h3 id = "the-slaved-datastore" > < a class = "header" href = "#the-slaved-datastore" > The Slaved DataStore< / a > < / h3 >
< p > There are read-only version of the synapse storage layer in
< code > synapse/replication/slave/storage< / code > that use the response of the
replication API to invalidate their caches.< / p >
< / main >
< nav class = "nav-wrapper" aria-label = "Page navigation" >
<!-- Mobile navigation buttons -->
< a rel = "prev" href = "log_contexts.html" class = "mobile-nav-chapters previous" title = "Previous chapter" aria-label = "Previous chapter" aria-keyshortcuts = "Left" >
< i class = "fa fa-angle-left" > < / i >
< / a >
< a rel = "next" href = "tcp_replication.html" class = "mobile-nav-chapters next" title = "Next chapter" aria-label = "Next chapter" aria-keyshortcuts = "Right" >
< i class = "fa fa-angle-right" > < / i >
< / a >
< div style = "clear: both" > < / div >
< / nav >
< / div >
< / div >
< nav class = "nav-wide-wrapper" aria-label = "Page navigation" >
< a rel = "prev" href = "log_contexts.html" class = "nav-chapters previous" title = "Previous chapter" aria-label = "Previous chapter" aria-keyshortcuts = "Left" >
< i class = "fa fa-angle-left" > < / i >
< / a >
< a rel = "next" href = "tcp_replication.html" class = "nav-chapters next" title = "Next chapter" aria-label = "Next chapter" aria-keyshortcuts = "Right" >
< i class = "fa fa-angle-right" > < / i >
< / a >
< / nav >
< / div >
< script type = "text/javascript" >
window.playground_copyable = true;
< / script >
< script src = "elasticlunr.min.js" type = "text/javascript" charset = "utf-8" > < / script >
< script src = "mark.min.js" type = "text/javascript" charset = "utf-8" > < / script >
< script src = "searcher.js" type = "text/javascript" charset = "utf-8" > < / script >
< script src = "clipboard.min.js" type = "text/javascript" charset = "utf-8" > < / script >
< script src = "highlight.js" type = "text/javascript" charset = "utf-8" > < / script >
< script src = "book.js" type = "text/javascript" charset = "utf-8" > < / script >
<!-- Custom JS scripts -->
< script type = "text/javascript" src = "docs/website_files/table-of-contents.js" > < / script >
2023-12-11 17:57:10 +03:00
< script type = "text/javascript" src = "docs/website_files/version-picker.js" > < / script >
< script type = "text/javascript" src = "docs/website_files/version.js" > < / script >
2022-02-01 14:04:50 +03:00
< / body >
2023-12-11 17:57:10 +03:00
< / html >
