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diff --git a/v1.48/development/database_schema.html b/v1.48/development/database_schema.html new file mode 100644 index 0000000000..ebe07774d8 --- /dev/null +++ b/v1.48/development/database_schema.html @@ -0,0 +1,376 @@ +<!DOCTYPE HTML> +<html lang="en" class="sidebar-visible no-js light"> + <head> + <!-- Book generated using mdBook --> + <meta charset="UTF-8"> + <title>Database Schemas - 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"> + + + + </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 ? 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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 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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 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/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 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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></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 class="chapter-item expanded "><a href="../usage/administration/request_log.html">Request log format</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/git.html">Git Usage</a></li><li class="chapter-item expanded "><div>Testing</div></li><li class="chapter-item expanded "><a href="../opentracing.html">OpenTracing</a></li><li class="chapter-item expanded "><a href="../development/database_schema.html" class="active">Database Schemas</a></li><li class="chapter-item expanded "><a href="../development/experimental_features.html">Experimental features</a></li><li class="chapter-item expanded "><div>Synapse Architecture</div></li><li><ol class="section"><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></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></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" 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(Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar"> + <i class="fa fa-search"></i> + </button> + + </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/development/database_schema.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="synapse-database-schema-files"><a class="header" href="#synapse-database-schema-files">Synapse database schema files</a></h1> +<p>Synapse's database schema is stored in the <code>synapse.storage.schema</code> module.</p> +<h2 id="logical-databases"><a class="header" href="#logical-databases">Logical databases</a></h2> +<p>Synapse supports splitting its datastore across multiple physical databases (which can +be useful for large installations), and the schema files are therefore split according +to the logical database they apply to.</p> +<p>At the time of writing, the following "logical" databases are supported:</p> +<ul> +<li><code>state</code> - used to store Matrix room state (more specifically, <code>state_groups</code>, +their relationships and contents).</li> +<li><code>main</code> - stores everything else.</li> +</ul> +<p>Additionally, the <code>common</code> directory contains schema files for tables which must be +present on <em>all</em> physical databases.</p> +<h2 id="synapse-schema-versions"><a class="header" href="#synapse-schema-versions">Synapse schema versions</a></h2> +<p>Synapse manages its database schema via "schema versions". These are mainly used to +help avoid confusion if the Synapse codebase is rolled back after the database is +updated. They work as follows:</p> +<ul> +<li> +<p>The Synapse codebase defines a constant <code>synapse.storage.schema.SCHEMA_VERSION</code> +which represents the expectations made about the database by that version. For +example, as of Synapse v1.36, this is <code>59</code>.</p> +</li> +<li> +<p>The database stores a "compatibility version" in +<code>schema_compat_version.compat_version</code> which defines the <code>SCHEMA_VERSION</code> of the +oldest version of Synapse which will work with the database. On startup, if +<code>compat_version</code> is found to be newer than <code>SCHEMA_VERSION</code>, Synapse will refuse to +start.</p> +<p>Synapse automatically updates this field from +<code>synapse.storage.schema.SCHEMA_COMPAT_VERSION</code>.</p> +</li> +<li> +<p>Whenever a backwards-incompatible change is made to the database format (normally +via a <code>delta</code> file), <code>synapse.storage.schema.SCHEMA_COMPAT_VERSION</code> is also updated +so that administrators can not accidentally roll back to a too-old version of Synapse.</p> +</li> +</ul> +<p>Generally, the goal is to maintain compatibility with at least one or two previous +releases of Synapse, so any substantial change tends to require multiple releases and a +bit of forward-planning to get right.</p> +<p>As a worked example: we want to remove the <code>room_stats_historical</code> table. Here is how it +might pan out.</p> +<ol> +<li> +<p>Replace any code that <em>reads</em> from <code>room_stats_historical</code> with alternative +implementations, but keep writing to it in case of rollback to an earlier version. +Also, increase <code>synapse.storage.schema.SCHEMA_VERSION</code>. In this +instance, there is no existing code which reads from <code>room_stats_historical</code>, so +our starting point is:</p> +<p>v1.36.0: <code>SCHEMA_VERSION=59</code>, <code>SCHEMA_COMPAT_VERSION=59</code></p> +</li> +<li> +<p>Next (say in Synapse v1.37.0): remove the code that <em>writes</em> to +<code>room_stats_historical</code>, but don’t yet remove the table in case of rollback to +v1.36.0. Again, we increase <code>synapse.storage.schema.SCHEMA_VERSION</code>, but +because we have not broken compatibility with v1.36, we do not yet update +<code>SCHEMA_COMPAT_VERSION</code>. We now have:</p> +<p>v1.37.0: <code>SCHEMA_VERSION=60</code>, <code>SCHEMA_COMPAT_VERSION=59</code>.</p> +</li> +<li> +<p>Later (say in Synapse v1.38.0): we can remove the table altogether. This will +break compatibility with v1.36.0, so we must update <code>SCHEMA_COMPAT_VERSION</code> accordingly. +There is no need to update <code>synapse.storage.schema.SCHEMA_VERSION</code>, since there is no +change to the Synapse codebase here. So we end up with:</p> +<p>v1.38.0: <code>SCHEMA_VERSION=60</code>, <code>SCHEMA_COMPAT_VERSION=60</code>.</p> +</li> +</ol> +<p>If in doubt about whether to update <code>SCHEMA_VERSION</code> or not, it is generally best to +lean towards doing so.</p> +<h2 id="full-schema-dumps"><a class="header" href="#full-schema-dumps">Full schema dumps</a></h2> +<p>In the <code>full_schemas</code> directories, only the most recently-numbered snapshot is used +(<code>54</code> at the time of writing). Older snapshots (eg, <code>16</code>) are present for historical +reference only.</p> +<h3 id="building-full-schema-dumps"><a class="header" href="#building-full-schema-dumps">Building full schema dumps</a></h3> +<p>If you want to recreate these schemas, they need to be made from a database that +has had all background updates run.</p> +<p>To do so, use <code>scripts-dev/make_full_schema.sh</code>. This will produce new +<code>full.sql.postgres</code> and <code>full.sql.sqlite</code> files.</p> +<p>Ensure postgres is installed, then run:</p> +<pre><code class="language-sh">./scripts-dev/make_full_schema.sh -p postgres_username -o output_dir/ +</code></pre> +<p>NB at the time of writing, this script predates the split into separate <code>state</code>/<code>main</code> +databases so will require updates to handle that correctly.</p> +<h2 id="boolean-columns"><a class="header" href="#boolean-columns">Boolean columns</a></h2> +<p>Boolean columns require special treatment, since SQLite treats booleans the +same as integers.</p> +<p>There are three separate aspects to this:</p> +<ul> +<li> +<p>Any new boolean column must be added to the <code>BOOLEAN_COLUMNS</code> list in +<code>scripts/synapse_port_db</code>. This tells the port script to cast the integer +value from SQLite to a boolean before writing the value to the postgres +database.</p> +</li> +<li> +<p>Before SQLite 3.23, <code>TRUE</code> and <code>FALSE</code> were not recognised as constants by +SQLite, and the <code>IS [NOT] TRUE</code>/<code>IS [NOT] FALSE</code> operators were not +supported. This makes it necessary to avoid using <code>TRUE</code> and <code>FALSE</code> +constants in SQL commands.</p> +<p>For example, to insert a <code>TRUE</code> value into the database, write:</p> +<pre><code class="language-python">txn.execute("INSERT INTO tbl(col) VALUES (?)", (True, )) +</code></pre> +</li> +<li> +<p>Default values for new boolean columns present a particular +difficulty. Generally it is best to create separate schema files for +Postgres and SQLite. For example:</p> +<pre><code class="language-sql"># in 00delta.sql.postgres: +ALTER TABLE tbl ADD COLUMN col BOOLEAN DEFAULT FALSE; +</code></pre> +<pre><code class="language-sql"># in 00delta.sql.sqlite: +ALTER TABLE tbl ADD COLUMN col BOOLEAN DEFAULT 0; +</code></pre> +<p>Note that there is a particularly insidious failure mode here: the Postgres +flavour will be accepted by SQLite 3.22, but will give a column whose +default value is the <strong>string</strong> <code>"FALSE"</code> - which, when cast back to a boolean +in Python, evaluates to <code>True</code>.</p> +</li> +</ul> + + </main> + + <nav class="nav-wrapper" aria-label="Page navigation"> + <!-- Mobile navigation buttons --> + + <a rel="prev" href="../opentracing.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="../development/experimental_features.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="../opentracing.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="../development/experimental_features.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> + + + + + </body> +</html> \ No newline at end of file |