To start streaming changes from your Postgres database, connect Sequin to your database. This guide is for a vanilla Postgres database, such as one you run locally or host yourself on a cloud provider. If you’re using a database provider, see the setup guide for your database provider:

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Prerequisites

If you’re running Sequin locally, be sure to install and configure Sequin first. You’ll need permission to create publications and replication slots on your database. You may also need administration privileges on your database if logical replication is not configured (more below).

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Provision a Postgres user for Sequin

When in development, it’s probably fine to supply Sequin with an existing user. However, when in production, you should create a dedicated user for Sequin. The user needs the following permissions:
  1. connect permission on the database.
  2. select permission on all the tables you want to connect to Sequin.
  3. replication permission to read from replication slots.
Here’s how to create a dedicated user with the minimum required permissions: 
-- Create user with a secure password
create user sequin_user with password 'REPLACE_WITH_SECURE_PASSWORD';

-- Grant connect permission
grant connect on database your_database to sequin_user;

-- Grant select permission on tables you want to replicate
grant select on table table1, table2, table3 to sequin_user;
-- OR grant select on all tables in a schema
grant select on all tables in schema public to sequin_user;

-- Grant replication permission
alter user sequin_user with replication;
To generate a secure password, if you have OpenSSL installed, you can use the following command: 
openssl rand -base64 32

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Enable logical replication

Sequin uses logical replication to capture changes from your Postgres database. To find out if logical replication is enabled on your database, connect to your database and run the following SQL command: 
show wal_level;
The wal_level must be set to logical. If it’s not, you’ll need to enable it. Note that this requires a restart of your database. Follow these steps to enable logical replication:
1

Locate your postgresql.conf file

The location varies by platform:
  • Linux: Usually in /etc/postgresql/<version>/main/postgresql.conf
  • macOS (Homebrew): /usr/local/var/postgresql@<version>/postgresql.conf
  • Windows: C:\Program Files\PostgreSQL\<version>\data\postgresql.conf
You can also find it by running:
show config_file;
2

Edit postgresql.conf

Open postgresql.conf in your text editor and set:
wal_level = logical
If you can’t find the wal_level setting, add it at the end of the file.
3

Restart PostgreSQL

Restart PostgreSQL to apply the changes:Linux:
sudo systemctl restart postgresql
macOS:
brew services restart postgresql@<version>
Windows:
net stop postgresql
net start postgresql
After restarting, run the show wal_level; command again to verify the change took effect.

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Connect Sequin to your database

In the Sequin Console, navigate to the “Databases” tab and click “Connect Database”.

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Database connection details

Fill in the connection details for your database:
  • Host: The host address of your database.
  • Port: The port number of your database.
  • Database: The name of your database.
  • Username: The username Sequin will use to connect to your database.
  • Password: The password Sequin will use to connect to your database.

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(Sequin Cloud) Connect to local database

If you’re using Sequin Cloud, you can connect Sequin to a database running on your local machine. Click “Use localhost” and follow the instructions. The “Host” and “Port” fields will be disabled. You’ll need the Sequin CLI installed to use this method.

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Replication configuration

1

Slot name and publication name

Fill in the “Slot name” and “Publication name” that you’d like Sequin to use.
2

Create slot and publication

Follow the instructions to create the slot and publication on your database.The simplest publication is one that includes all tables:
create publication sequin_pub for all tables with (publish_via_partition_root = true);
However, you can also create a publication that includes specific tables or schemas. You’ll just need to modify the publication as needed in the future.
Be sure to create the publication before you create the slot.

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Test and connect

1

Test connection

Click “Test connection” to verify that Sequin can connect to your database.
2

Connect

Once the test goes green, click “Connect” to finish the connection process.

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Monitoring

Sequin will run health checks against your database connection automatically. You can view the status of the connection at any time in your database’s “Overview” page.

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Adding tables to your publication

If you created a publication that contained a subset of your tables, you can add more tables to the publication later. To add tables to an existing publication, use the alter publication command: 
alter publication sequin_pub add table table1, table2;
You can also add all tables in a specific schema: 
alter publication sequin_pub add tables in schema my_schema;
To verify which tables are included in your publication, you can run: 
select * from pg_publication_tables
where pubname = 'sequin_pub';
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