Generic Postgres source setup guide

Set up any Postgres instance as a source for ClickPipes

If you use one of the supported providers (in the sidebar), please refer to the specific guide for that provider.

ClickPipes supports Postgres version 12 and later.

Enable logical replication

1. To enable replication on your Postgres instance, we need to make sure that the following settings are set:

   wal_level = logical
   

   To check the same, you can run the following SQL command:

   SHOW wal_level;
   

   The output should be logical. If not, run:

   ALTER SYSTEM SET wal_level = logical;
   

2. Additionally, the following settings are recommended to be set on the Postgres instance:

   max_wal_senders > 1
   max_replication_slots >= 4
   

   To check the same, you can run the following SQL commands:

   SHOW max_wal_senders;
   SHOW max_replication_slots;
   

   If the values don’t match the recommended values, you can run the following SQL commands to set them:

   ALTER SYSTEM SET max_wal_senders = 10;
   ALTER SYSTEM SET max_replication_slots = 10;
   

3. If you have made any changes to the configuration as mentioned above, you NEED to RESTART the Postgres instance for the changes to take effect.

Creating a user with permissions and publication

Connect to your Postgres instance as an admin user and execute the following commands:

1. Create a dedicated user for ClickPipes:

   CREATE USER clickpipes_user PASSWORD 'some-password';
   

2. Grant schema-level, read-only access to the user you created in the previous step. The following example shows permissions for the public schema. Repeat these commands for each schema containing tables you want to replicate:

   GRANT USAGE ON SCHEMA "public" TO clickpipes_user;
   GRANT SELECT ON ALL TABLES IN SCHEMA "public" TO clickpipes_user;
   ALTER DEFAULT PRIVILEGES IN SCHEMA "public" GRANT SELECT ON TABLES TO clickpipes_user;
   

3. Grant replication privileges to the user:

   ALTER USER clickpipes_user WITH REPLICATION;
   

4. Create a publication with the tables you want to replicate. We strongly recommend only including the tables you need in the publication to avoid performance overhead.

Any table included in the publication must either have a primary key defined or have its replica identity configured to FULL. See the Postgres FAQs for guidance on scoping.

• To create a publication for specific tables:

  CREATE PUBLICATION clickpipes FOR TABLE table_to_replicate, table_to_replicate2;
  

• To create a publication for all tables in a specific schema:

  CREATE PUBLICATION clickpipes FOR TABLES IN SCHEMA "public";
  

The clickpipes publication will contain the set of change events generated from the specified tables, and will later be used to ingest the replication stream.

Enabling connections in pg_hba.conf to the ClickPipes User

If you’re self serving, you need to allow connections to the ClickPipes user from the ClickPipes IP addresses by following the below steps. If you’re using a managed service, you can do the same by following the provider’s documentation.

1. Make necessary changes to the pg_hba.conf file to allow connections to the ClickPipes user from the ClickPipes IP addresses. An example entry in the pg_hba.conf file would look like:

   host    all   clickpipes_user     0.0.0.0/0          scram-sha-256
   

2. Reload the PostgreSQL instance for the changes to take effect:

   SELECT pg_reload_conf();
   

Increase max_slot_wal_keep_size

This is a recommended configuration change to ensure that large transactions/commits don’t cause the replication slot to be dropped.

You can increase the max_slot_wal_keep_size parameter for your PostgreSQL instance to a higher value (at least 100GB or 102400) by updating the postgresql.conf file.

max_slot_wal_keep_size = 102400

You can reload the Postgres instance for the changes to take effect:

SELECT pg_reload_conf();

For better recommendation of this value you can contact the ClickPipes team.

What’s next?

You can now create your ClickPipe and start ingesting data from your Postgres instance into ClickHouse Cloud. Make sure to note down the connection details you used while setting up your Postgres instance as you will need them during the ClickPipe creation process.