mirror of
https://github.com/element-hq/synapse.git
synced 2024-11-24 18:45:52 +03:00
361 lines
32 KiB
HTML
361 lines
32 KiB
HTML
<!DOCTYPE HTML>
|
|
<html lang="en" class="sidebar-visible no-js light">
|
|
<head>
|
|
<!-- Book generated using mdBook -->
|
|
<meta charset="UTF-8">
|
|
<title>Message Retention Policies - 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">
|
|
<link rel="stylesheet" href="docs/website_files/version-picker.css">
|
|
</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><ol class="section"><li class="chapter-item expanded "><a href="setup/turn/coturn.html">coturn TURN server</a></li><li class="chapter-item expanded "><a href="setup/turn/eturnal.html">eturnal TURN server</a></li></ol></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 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/config_documentation.html">Configuration Manual</a></li><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="user_directory.html">User Directory</a></li><li class="chapter-item expanded "><a href="message_retention_policies.html" class="active">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 href="modules/presence_router_callbacks.html">Presence router callbacks</a></li><li class="chapter-item expanded "><a href="modules/account_validity_callbacks.html">Account validity callbacks</a></li><li class="chapter-item expanded "><a href="modules/password_auth_provider_callbacks.html">Password auth provider callbacks</a></li><li class="chapter-item expanded "><a href="modules/background_update_controller_callbacks.html">Background update controller callbacks</a></li><li class="chapter-item expanded "><a href="modules/account_data_callbacks.html">Account data callbacks</a></li><li class="chapter-item expanded "><a href="modules/porting_legacy_module.html">Porting a legacy module to the new interface</a></li></ol></li></ol></li><li class="chapter-item expanded "><a href="workers.html">Workers</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="synctl_workers.html">Using synctl with Workers</a></li><li class="chapter-item expanded "><a href="systemd-with-workers/index.html">Systemd</a></li></ol></li></ol></li><li class="chapter-item expanded "><a href="usage/administration/index.html">Administration</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="usage/administration/admin_api/index.html">Admin API</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="admin_api/account_validity.html">Account Validity</a></li><li class="chapter-item expanded "><a href="usage/administration/admin_api/background_updates.html">Background Updates</a></li><li class="chapter-item expanded "><a href="admin_api/event_reports.html">Event Reports</a></li><li class="chapter-item expanded "><a href="admin_api/media_admin_api.html">Media</a></li><li class="chapter-item expanded "><a href="admin_api/purge_history_api.html">Purge History</a></li><li class="chapter-item expanded "><a href="admin_api/register_api.html">Register Users</a></li><li class="chapter-item expanded "><a href="usage/administration/admin_api/registration_tokens.html">Registration Tokens</a></li><li class="chapter-item expanded "><a href="admin_api/room_membership.html">Manipulate Room Membership</a></li><li class="chapter-item expanded "><a href="admin_api/rooms.html">Rooms</a></li><li class="chapter-item expanded "><a href="admin_api/server_notices.html">Server Notices</a></li><li class="chapter-item expanded "><a href="admin_api/statistics.html">Statistics</a></li><li class="chapter-item expanded "><a href="admin_api/user_admin_api.html">Users</a></li><li class="chapter-item expanded "><a href="admin_api/version_api.html">Server Version</a></li><li class="chapter-item expanded "><a href="usage/administration/admin_api/federation.html">Federation</a></li></ol></li><li class="chapter-item expanded "><a href="manhole.html">Manhole</a></li><li class="chapter-item expanded "><a href="metrics-howto.html">Monitoring</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="usage/administration/monitoring/reporting_homeserver_usage_statistics.html">Reporting Homeserver Usage Statistics</a></li></ol></li><li class="chapter-item expanded "><a href="usage/administration/monthly_active_users.html">Monthly Active Users</a></li><li class="chapter-item expanded "><a href="usage/administration/understanding_synapse_through_grafana_graphs.html">Understanding Synapse Through Grafana Graphs</a></li><li class="chapter-item expanded "><a href="usage/administration/useful_sql_for_admins.html">Useful SQL for Admins</a></li><li class="chapter-item expanded "><a href="usage/administration/database_maintenance_tools.html">Database Maintenance Tools</a></li><li class="chapter-item expanded "><a href="usage/administration/state_groups.html">State Groups</a></li><li class="chapter-item expanded "><a href="usage/administration/request_log.html">Request log format</a></li><li class="chapter-item expanded "><a href="usage/administration/admin_faq.html">Admin FAQ</a></li><li class="chapter-item expanded "><div>Scripts</div></li></ol></li><li class="chapter-item expanded "><li class="part-title">Development</li><li class="chapter-item expanded "><a href="development/contributing_guide.html">Contributing Guide</a></li><li class="chapter-item expanded "><a href="code_style.html">Code Style</a></li><li class="chapter-item expanded "><a href="development/reviews.html">Reviewing Code</a></li><li class="chapter-item expanded "><a href="development/releases.html">Release Cycle</a></li><li class="chapter-item expanded "><a href="development/git.html">Git Usage</a></li><li class="chapter-item expanded "><div>Testing</div></li><li><ol class="section"><li class="chapter-item expanded "><a href="development/demo.html">Demo scripts</a></li></ol></li><li class="chapter-item expanded "><a href="opentracing.html">OpenTracing</a></li><li class="chapter-item expanded "><a href="development/database_schema.html">Database Schemas</a></li><li class="chapter-item expanded "><a href="development/experimental_features.html">Experimental features</a></li><li class="chapter-item expanded "><a href="development/dependencies.html">Dependency management</a></li><li class="chapter-item expanded "><div>Synapse Architecture</div></li><li><ol class="section"><li class="chapter-item expanded "><a href="development/synapse_architecture/cancellation.html">Cancellation</a></li><li class="chapter-item expanded "><a href="log_contexts.html">Log Contexts</a></li><li class="chapter-item expanded "><a href="replication.html">Replication</a></li><li class="chapter-item expanded "><a href="tcp_replication.html">TCP Replication</a></li><li class="chapter-item expanded "><a href="development/synapse_architecture/faster_joins.html">Faster remote joins</a></li></ol></li><li class="chapter-item expanded "><a href="development/internal_documentation/index.html">Internal Documentation</a></li><li><ol class="section"><li class="chapter-item expanded "><div>Single Sign-On</div></li><li><ol class="section"><li class="chapter-item expanded "><a href="development/saml.html">SAML</a></li><li class="chapter-item expanded "><a href="development/cas.html">CAS</a></li></ol></li><li class="chapter-item expanded "><a href="development/room-dag-concepts.html">Room DAG concepts</a></li><li class="chapter-item expanded "><div>State Resolution</div></li><li><ol class="section"><li class="chapter-item expanded "><a href="auth_chain_difference_algorithm.html">The Auth Chain Difference Algorithm</a></li></ol></li><li class="chapter-item expanded "><a href="media_repository.html">Media Repository</a></li><li class="chapter-item expanded "><a href="room_and_user_statistics.html">Room and User Statistics</a></li></ol></li><li class="chapter-item expanded "><div>Scripts</div></li><li class="chapter-item expanded affix "><li class="part-title">Other</li><li class="chapter-item expanded "><a href="deprecation_policy.html">Dependency Deprecation Policy</a></li><li class="chapter-item expanded "><a href="other/running_synapse_on_single_board_computers.html">Running Synapse on a Single-Board Computer</a></li></ol>
|
|
</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>
|
|
<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>
|
|
</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/message_retention_policies.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="message-retention-policies"><a class="header" href="#message-retention-policies">Message retention policies</a></h1>
|
|
<p>Synapse admins can enable support for message retention policies on
|
|
their homeserver. Message retention policies exist at a room level,
|
|
follow the semantics described in
|
|
<a href="https://github.com/matrix-org/matrix-doc/blob/matthew/msc1763/proposals/1763-configurable-retention-periods.md">MSC1763</a>,
|
|
and allow server and room admins to configure how long messages should
|
|
be kept in a homeserver's database before being purged from it.
|
|
<strong>Please note that, as this feature isn't part of the Matrix
|
|
specification yet, this implementation is to be considered as
|
|
experimental. There are known bugs which may cause database corruption.
|
|
Proceed with caution.</strong> </p>
|
|
<p>A message retention policy is mainly defined by its <code>max_lifetime</code>
|
|
parameter, which defines how long a message can be kept around after
|
|
it was sent to the room. If a room doesn't have a message retention
|
|
policy, and there's no default one for a given server, then no message
|
|
sent in that room is ever purged on that server.</p>
|
|
<p>MSC1763 also specifies semantics for a <code>min_lifetime</code> parameter which
|
|
defines the amount of time after which an event <em>can</em> get purged (after
|
|
it was sent to the room), but Synapse doesn't currently support it
|
|
beyond registering it.</p>
|
|
<p>Both <code>max_lifetime</code> and <code>min_lifetime</code> are optional parameters.</p>
|
|
<p>Note that message retention policies don't apply to state events.</p>
|
|
<p>Once an event reaches its expiry date (defined as the time it was sent
|
|
plus the value for <code>max_lifetime</code> in the room), two things happen:</p>
|
|
<ul>
|
|
<li>Synapse stops serving the event to clients via any endpoint.</li>
|
|
<li>The message gets picked up by the next purge job (see the "Purge jobs"
|
|
section) and is removed from Synapse's database.</li>
|
|
</ul>
|
|
<p>Since purge jobs don't run continuously, this means that an event might
|
|
stay in a server's database for longer than the value for <code>max_lifetime</code>
|
|
in the room would allow, though hidden from clients.</p>
|
|
<p>Similarly, if a server (with support for message retention policies
|
|
enabled) receives from another server an event that should have been
|
|
purged according to its room's policy, then the receiving server will
|
|
process and store that event until it's picked up by the next purge job,
|
|
though it will always hide it from clients.</p>
|
|
<p>Synapse requires at least one message in each room, so it will never
|
|
delete the last message in a room. It will, however, hide it from
|
|
clients.</p>
|
|
<h2 id="server-configuration"><a class="header" href="#server-configuration">Server configuration</a></h2>
|
|
<p>Support for this feature can be enabled and configured by adding a the
|
|
<code>retention</code> in the Synapse configuration file (see
|
|
<a href="usage/configuration/config_documentation.html#retention">configuration manual</a>).</p>
|
|
<p>To enable support for message retention policies, set the setting
|
|
<code>enabled</code> in this section to <code>true</code>.</p>
|
|
<h3 id="default-policy"><a class="header" href="#default-policy">Default policy</a></h3>
|
|
<p>A default message retention policy is a policy defined in Synapse's
|
|
configuration that is used by Synapse for every room that doesn't have a
|
|
message retention policy configured in its state. This allows server
|
|
admins to ensure that messages are never kept indefinitely in a server's
|
|
database. </p>
|
|
<p>A default policy can be defined as such, by adding the <code>retention</code> option in
|
|
the configuration file and adding these sub-options:</p>
|
|
<pre><code class="language-yaml">default_policy:
|
|
min_lifetime: 1d
|
|
max_lifetime: 1y
|
|
</code></pre>
|
|
<p>Here, <code>min_lifetime</code> and <code>max_lifetime</code> have the same meaning and level
|
|
of support as previously described. They can be expressed either as a
|
|
duration (using the units <code>s</code> (seconds), <code>m</code> (minutes), <code>h</code> (hours),
|
|
<code>d</code> (days), <code>w</code> (weeks) and <code>y</code> (years)) or as a number of milliseconds.</p>
|
|
<h3 id="purge-jobs"><a class="header" href="#purge-jobs">Purge jobs</a></h3>
|
|
<p>Purge jobs are the jobs that Synapse runs in the background to purge
|
|
expired events from the database. They are only run if support for
|
|
message retention policies is enabled in the server's configuration. If
|
|
no configuration for purge jobs is configured by the server admin,
|
|
Synapse will use a default configuration, which is described here in the
|
|
<a href="usage/configuration/config_documentation.html#retention">configuration manual</a>.</p>
|
|
<p>Some server admins might want a finer control on when events are removed
|
|
depending on an event's room's policy. This can be done by setting the
|
|
<code>purge_jobs</code> sub-section in the <code>retention</code> section of the configuration
|
|
file. An example of such configuration could be:</p>
|
|
<pre><code class="language-yaml">purge_jobs:
|
|
- longest_max_lifetime: 3d
|
|
interval: 12h
|
|
- shortest_max_lifetime: 3d
|
|
longest_max_lifetime: 1w
|
|
interval: 1d
|
|
- shortest_max_lifetime: 1w
|
|
interval: 2d
|
|
</code></pre>
|
|
<p>In this example, we define three jobs:</p>
|
|
<ul>
|
|
<li>one that runs twice a day (every 12 hours) and purges events in rooms
|
|
which policy's <code>max_lifetime</code> is lower or equal to 3 days.</li>
|
|
<li>one that runs once a day and purges events in rooms which policy's
|
|
<code>max_lifetime</code> is between 3 days and a week.</li>
|
|
<li>one that runs once every 2 days and purges events in rooms which
|
|
policy's <code>max_lifetime</code> is greater than a week.</li>
|
|
</ul>
|
|
<p>Note that this example is tailored to show different configurations and
|
|
features slightly more jobs than it's probably necessary (in practice, a
|
|
server admin would probably consider it better to replace the two last
|
|
jobs with one that runs once a day and handles rooms which
|
|
policy's <code>max_lifetime</code> is greater than 3 days).</p>
|
|
<p>Keep in mind, when configuring these jobs, that a purge job can become
|
|
quite heavy on the server if it targets many rooms, therefore prefer
|
|
having jobs with a low interval that target a limited set of rooms. Also
|
|
make sure to include a job with no minimum and one with no maximum to
|
|
make sure your configuration handles every policy.</p>
|
|
<p>As previously mentioned in this documentation, while a purge job that
|
|
runs e.g. every day means that an expired event might stay in the
|
|
database for up to a day after its expiry, Synapse hides expired events
|
|
from clients as soon as they expire, so the event is not visible to
|
|
local users between its expiry date and the moment it gets purged from
|
|
the server's database.</p>
|
|
<h3 id="lifetime-limits"><a class="header" href="#lifetime-limits">Lifetime limits</a></h3>
|
|
<p>Server admins can set limits on the values of <code>max_lifetime</code> to use when
|
|
purging old events in a room. These limits can be defined under the
|
|
<code>retention</code> option in the configuration file:</p>
|
|
<pre><code class="language-yaml">allowed_lifetime_min: 1d
|
|
allowed_lifetime_max: 1y
|
|
</code></pre>
|
|
<p>The limits are considered when running purge jobs. If necessary, the
|
|
effective value of <code>max_lifetime</code> will be brought between
|
|
<code>allowed_lifetime_min</code> and <code>allowed_lifetime_max</code> (inclusive).
|
|
This means that, if the value of <code>max_lifetime</code> defined in the room's state
|
|
is lower than <code>allowed_lifetime_min</code>, the value of <code>allowed_lifetime_min</code>
|
|
will be used instead. Likewise, if the value of <code>max_lifetime</code> is higher
|
|
than <code>allowed_lifetime_max</code>, the value of <code>allowed_lifetime_max</code> will be
|
|
used instead.</p>
|
|
<p>In the example above, we ensure Synapse never deletes events that are less
|
|
than one day old, and that it always deletes events that are over a year
|
|
old.</p>
|
|
<p>If a default policy is set, and its <code>max_lifetime</code> value is lower than
|
|
<code>allowed_lifetime_min</code> or higher than <code>allowed_lifetime_max</code>, the same
|
|
process applies.</p>
|
|
<p>Both parameters are optional; if one is omitted Synapse won't use it to
|
|
adjust the effective value of <code>max_lifetime</code>.</p>
|
|
<p>Like other settings in this section, these parameters can be expressed
|
|
either as a duration or as a number of milliseconds.</p>
|
|
<h2 id="room-configuration"><a class="header" href="#room-configuration">Room configuration</a></h2>
|
|
<p>To configure a room's message retention policy, a room's admin or
|
|
moderator needs to send a state event in that room with the type
|
|
<code>m.room.retention</code> and the following content:</p>
|
|
<pre><code class="language-json">{
|
|
"max_lifetime": ...
|
|
}
|
|
</code></pre>
|
|
<p>In this event's content, the <code>max_lifetime</code> parameter has the same
|
|
meaning as previously described, and needs to be expressed in
|
|
milliseconds. The event's content can also include a <code>min_lifetime</code>
|
|
parameter, which has the same meaning and limited support as previously
|
|
described.</p>
|
|
<p>Note that over every server in the room, only the ones with support for
|
|
message retention policies will actually remove expired events. This
|
|
support is currently not enabled by default in Synapse.</p>
|
|
<h2 id="note-on-reclaiming-disk-space"><a class="header" href="#note-on-reclaiming-disk-space">Note on reclaiming disk space</a></h2>
|
|
<p>While purge jobs actually delete data from the database, the disk space
|
|
used by the database might not decrease immediately on the database's
|
|
host. However, even though the database engine won't free up the disk
|
|
space, it will start writing new data into where the purged data was.</p>
|
|
<p>If you want to reclaim the freed disk space anyway and return it to the
|
|
operating system, the server admin needs to run <code>VACUUM FULL;</code> (or
|
|
<code>VACUUM;</code> for SQLite databases) on Synapse's database (see the related
|
|
<a href="https://www.postgresql.org/docs/current/sql-vacuum.html">PostgreSQL documentation</a>).</p>
|
|
|
|
</main>
|
|
|
|
<nav class="nav-wrapper" aria-label="Page navigation">
|
|
<!-- Mobile navigation buttons -->
|
|
<a rel="prev" href="user_directory.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="modules/index.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="user_directory.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="modules/index.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>
|
|
<script type="text/javascript" src="docs/website_files/version-picker.js"></script>
|
|
<script type="text/javascript" src="docs/website_files/version.js"></script>
|
|
</body>
|
|
</html>
|