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PlanetScale for Postgres source setup guide

Info

PlanetScale for Postgres is currently in early access.

Supported Postgres versions​

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 by default. If not, please log into the PlanetScale console and go to Cluster configuration->Parameters and scroll down to Write-ahead log to change it.

Caution

Changing this in the PlanetScale console WILL trigger a restart.

  1. Additionally, it is recommended to increase the setting max_slot_wal_keep_size from its default of 4GB. This is also done via the PlanetScale console by going to Cluster configuration->Parameters and then scroll down to Write-ahead log. To help determine the new value, please take a look here.

Creating a user with permissions and publication​

Let's create a new user for ClickPipes with the necessary permissions suitable for CDC, and also create a publication that we'll use for replication.

For this, you can connect to your PlanetScale Postgres instance using the default postgres.<...> user and run the following SQL commands:

  CREATE USER clickpipes_user PASSWORD 'clickpipes_password';
  GRANT USAGE ON SCHEMA "public" TO clickpipes_user;
-- You may need to grant these permissions on more schemas depending on the tables you're moving
  GRANT SELECT ON ALL TABLES IN SCHEMA "public" TO clickpipes_user;
  ALTER DEFAULT PRIVILEGES IN SCHEMA "public" GRANT SELECT ON TABLES TO clickpipes_user;

-- Give replication permission to the USER
  ALTER USER clickpipes_user REPLICATION;

-- Create a publication. We will use this when creating the pipe
-- When adding new tables to the ClickPipe, you'll need to manually add them to the publication as well. 
  CREATE PUBLICATION clickpipes_publication FOR TABLE <...>, <...>, <...>;
Note

Make sure to replace clickpipes_user and clickpipes_password with your desired username and password.

Caveats​

  1. To connect to PlanetScale Postgres, the current branch needs to be appended to the username created above. For example, if the created user was named clickpipes_user, the actual user provided during the ClickPipe creation needs to be clickpipes_user.branch where branch refers to the "id" of the current PlanetScale Postgres branch. To quickly determine this, you can refer to the username of the postgres user you used to create the user earlier, the part after the period would be the branch id.
  2. Do not use the PSBouncer port (currently 6432) for CDC pipes connecting to PlanetScale Postgres, the normal port 5432 must be used. Either port may be used for initial-load only pipes.
  3. Please ensure you're connecting only to the primary instance, connecting to replica instances is currently not supported.

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.