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<p>If your server already has an admin account you should use the <ahref="../../admin_api/user_admin_api.html#change-whether-a-user-is-a-server-administrator-or-not">User Admin API</a> to promote other accounts to become admins.</p>
<p>If you don't have any admin accounts yet you won't be able to use the admin API, so you'll have to edit the database manually. Manually editing the database is generally not recommended so once you have an admin account: use the admin APIs to make further changes.</p>
<h2id="what-servers-are-my-server-talking-to"><aclass="header"href="#what-servers-are-my-server-talking-to">What servers are my server talking to?</a></h2>
<h2id="what-servers-are-currently-participating-in-this-room"><aclass="header"href="#what-servers-are-currently-participating-in-this-room">What servers are currently participating in this room?</a></h2>
INNER JOIN room_memberships AS m USING (room_id, event_id)
WHERE room_id = '!cURbafjkfsMDVwdRDQ:matrix.org' AND membership = 'join';
</code></pre>
<h2id="what-users-are-registered-on-my-server"><aclass="header"href="#what-users-are-registered-on-my-server">What users are registered on my server?</a></h2>
<h2id="i-have-a-problem-with-my-server-can-i-just-delete-my-database-and-start-again"><aclass="header"href="#i-have-a-problem-with-my-server-can-i-just-delete-my-database-and-start-again">I have a problem with my server. Can I just delete my database and start again?</a></h2>
<p>Deleting your database is unlikely to make anything better. </p>
<p>It's easy to make the mistake of thinking that you can start again from a clean slate by dropping your database, but things don't work like that in a federated network: lots of other servers have information about your server.</p>
<p>For example: other servers might think that you are in a room, your server will think that you are not, and you'll probably be unable to interact with that room in a sensible way ever again.</p>
<p>In general, there are better solutions to any problem than dropping the database. Come and seek help in https://matrix.to/#/#synapse:matrix.org.</p>
<p>There are two exceptions when it might be sensible to delete your database and start again:</p>
<ul>
<li>You have <em>never</em> joined any rooms which are federated with other servers. For instance, a local deployment which the outside world can't talk to. </li>
<li>You are changing the <code>server_name</code> in the homeserver configuration. In effect this makes your server a completely new one from the point of view of the network, so in this case it makes sense to start with a clean database.
(In both cases you probably also want to clear out the media_store.)</li>
</ul>
<h2id="ive-stuffed-up-access-to-my-room-how-can-i-delete-it-to-free-up-the-alias"><aclass="header"href="#ive-stuffed-up-access-to-my-room-how-can-i-delete-it-to-free-up-the-alias">I've stuffed up access to my room, how can I delete it to free up the alias?</a></h2>
<p><code><room-alias></code> - the room alias, eg. #my_room:matrix.org this possibly needs to be URL encoded also, for example %23my_room%3Amatrix.org</p>
<h2id="how-can-i-find-the-lines-corresponding-to-a-given-http-request-in-my-homeserver-log"><aclass="header"href="#how-can-i-find-the-lines-corresponding-to-a-given-http-request-in-my-homeserver-log">How can I find the lines corresponding to a given HTTP request in my homeserver log?</a></h2>
<p>Synapse tags each log line according to the HTTP request it is processing. When it finishes processing each request, it logs a line containing the words <code>Processed request: </code>. For example:</p>
<p>Here we can see that the request has been tagged with <code>GET-37</code>. (The tag depends on the method of the HTTP request, so might start with <code>GET-</code>, <code>PUT-</code>, <code>POST-</code>, <code>OPTIONS-</code> or <code>DELETE-</code>.) So to find all lines corresponding to this request, we can do:</p>
<p>If you want to paste that output into a github issue or matrix room, please remember to surround it with triple-backticks (```) to make it legible (see <ahref="https://help.github.com/en/articles/basic-writing-and-formatting-syntax#quoting-code">quoting code</a>).</p>
<h2id="what-do-all-those-fields-in-the-processed-line-mean"><aclass="header"href="#what-do-all-those-fields-in-the-processed-line-mean">What do all those fields in the 'Processed' line mean?</a></h2>
<h2id="what-are-the-biggest-rooms-on-my-server"><aclass="header"href="#what-are-the-biggest-rooms-on-my-server">What are the biggest rooms on my server?</a></h2>
<pre><codeclass="language-sql">SELECT s.canonical_alias, g.room_id, count(*) AS num_rows
<p>This is normally caused by a misconfiguration in your reverse-proxy. See <ahref="../../reverse_proxy.html">the reverse proxy docs</a> and double-check that your settings are correct.</p>
<h2id="help-synapse-is-slow-and-eats-all-my-ramcpu"><aclass="header"href="#help-synapse-is-slow-and-eats-all-my-ramcpu">Help!! Synapse is slow and eats all my RAM/CPU!</a></h2>
<p>First, ensure you are running the latest version of Synapse, using Python 3
with a <ahref="../../postgres.html">PostgreSQL database</a>.</p>
<p>Synapse's architecture is quite RAM hungry currently - we deliberately
cache a lot of recent room data and metadata in RAM in order to speed up
common requests. We'll improve this in the future, but for now the easiest
way to either reduce the RAM usage (at the risk of slowing things down)
is to set the almost-undocumented <code>SYNAPSE_CACHE_FACTOR</code> environment
variable. The default is 0.5, which can be decreased to reduce RAM usage
in memory constrained environments, or increased if performance starts to
degrade.</p>
<p>However, degraded performance due to a low cache factor, common on
machines with slow disks, often leads to explosions in memory use due
backlogged requests. In this case, reducing the cache factor will make
things worse. Instead, try increasing it drastically. 2.0 is a good
starting value.</p>
<p>Using <ahref="https://jemalloc.net">libjemalloc</a> can also yield a significant
improvement in overall memory use, and especially in terms of giving back
RAM to the OS. To use it, the library must simply be put in the
LD_PRELOAD environment variable when launching Synapse. On Debian, this
can be done by installing the <code>libjemalloc1</code> package and adding this
line to <code>/etc/default/matrix-synapse</code>:</p>
