Postgres version 9.5 or later is known to work.
Install postgres client libraries
Synapse will require the python postgres client library in order to connect to a postgres database.
If you are using the matrix.org debian/ubuntu packages, the necessary python library will already be installed, but you will need to ensure the low-level postgres library is installed, which you can do with
apt install libpq5.
For other pre-built packages, please consult the documentation from the relevant package.
If you installed synapse in a virtualenv, you can install the library with:
~/synapse/env/bin/pip install matrix-synapse[postgres]
(substituting the path to your virtualenv for
~/synapse/env, if you used a different path). You will require the postgres development files. These are in the
libpq-devpackage on Debian-derived distributions.
Set up database
Assuming your PostgreSQL database user is called
postgres, first authenticate as the database user with:
su - postgres # Or, if your system uses sudo to get administrative rights sudo -u postgres bash
Then, create a user
createuser --pwprompt synapse_user
Before you can authenticate with the
synapse_user, you must create a
database that it can access. To create a database, first connect to the
database with your database user:
su - postgres # Or: sudo -u postgres bash psql
and then run:
CREATE DATABASE synapse ENCODING 'UTF8' LC_COLLATE='C' LC_CTYPE='C' template=template0 OWNER synapse_user;
This would create an appropriate database named
synapse owned by the
synapse_user user (which must already have been created as above).
Note that the PostgreSQL database must have the correct encoding set (as shown above), otherwise it will not be able to store UTF8 strings.
You may need to enable password authentication so
connect to the database. See
The default settings should be fine for most deployments. For larger scale deployments tuning some of the settings is recommended, details of which can be found at https://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server.
In particular, we've found tuning the following values helpful for performance:
Note that the appropriate values for those fields depend on the amount of free memory the database host has available.
When you are ready to start using PostgreSQL, edit the
section in your config file to match the following lines:
database: name: psycopg2 args: user: <user> password: <pass> database: <db> host: <host> cp_min: 5 cp_max: 10
All key, values in
args are passed to the
function, except keys beginning with
cp_, which are consumed by the
twisted adbapi connection pool.
Porting from SQLite
synapse_port_db allows porting an existing synapse server
backed by SQLite to using PostgreSQL. This is done in as a two phase
- Copy the existing SQLite database to a separate location (while the server is down) and running the port script against that offline database.
- Shut down the server. Rerun the port script to port any data that has come in since taking the first snapshot. Restart server against the PostgreSQL database.
The port script is designed to be run repeatedly against newer snapshots of the SQLite database file. This makes it safe to repeat step 1 if there was a delay between taking the previous snapshot and being ready to do step 2.
It is safe to at any time kill the port script and restart it.
Using the port script
Firstly, shut down the currently running synapse server and copy its
database file (typically
homeserver.db) to another location. Once the
copy is complete, restart synapse. For instance:
./synctl stop cp homeserver.db homeserver.db.snapshot ./synctl start
Copy the old config file into a new config file:
cp homeserver.yaml homeserver-postgres.yaml
Edit the database section as described in the section Synapse config
above and with the SQLite snapshot located at
synapse_port_db --sqlite-database homeserver.db.snapshot \ --postgres-config homeserver-postgres.yaml
--curses displays a coloured curses progress UI.
If the script took a long time to complete, or time has otherwise passed since the original snapshot was taken, repeat the previous steps with a newer snapshot.
To complete the conversion shut down the synapse server and run the port
script one last time, e.g. if the SQLite database is at
synapse_port_db --sqlite-database homeserver.db \ --postgres-config homeserver-postgres.yaml
Once that has completed, change the synapse config to point at the
PostgreSQL database configuration file
./synctl stop mv homeserver.yaml homeserver-old-sqlite.yaml mv homeserver-postgres.yaml homeserver.yaml ./synctl start
Synapse should now be running against PostgreSQL.