> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-mintlify-3a82795f.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> Set up any Postgres instance as a source for ClickPipes

# Generic Postgres source setup guide

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

ClickPipes supports Postgres version 12 and later.

<h2 id="enable-logical-replication">
  Enable logical replication
</h2>

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

   ```sql theme={null}
   wal_level = logical
   ```

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

   ```sql theme={null}
   SHOW wal_level;
   ```

   The output should be `logical`. If not, run:

   ```sql theme={null}
   ALTER SYSTEM SET wal_level = logical;
   ```

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

   ```sql theme={null}
   max_wal_senders > 1
   max_replication_slots >= 4
   ```

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

   ```sql theme={null}
   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:

   ```sql theme={null}
   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.

<h2 id="creating-a-user-with-permissions-and-publication">
  Creating a user with permissions and publication
</h2>

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

1. Create a dedicated user for ClickPipes:

   ```sql theme={null}
   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:

   ```sql theme={null}
   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:

   ```sql theme={null}
   ALTER USER clickpipes_user WITH REPLICATION;
   ```

4. Create a [publication](https://www.postgresql.org/docs/current/logical-replication-publication.html) with the tables you want to replicate. We strongly recommend only including the tables you need in the publication to avoid performance overhead.

<Warning>
  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](/integrations/clickpipes/postgres/faq#how-should-i-scope-my-publications-when-setting-up-replication) for guidance on scoping.
</Warning>

* To create a publication for specific tables:

  ```sql theme={null}
  CREATE PUBLICATION clickpipes FOR TABLE table_to_replicate, table_to_replicate2;
  ```

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

  ```sql theme={null}
  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.

<h2 id="enabling-connections-in-pg_hbaconf-to-the-clickpipes-user">
  Enabling connections in pg\_hba.conf to the ClickPipes User
</h2>

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:
   ```response theme={null}
   host    all   clickpipes_user     0.0.0.0/0          scram-sha-256
   ```

2. Reload the PostgreSQL instance for the changes to take effect:
   ```sql theme={null}
   SELECT pg_reload_conf();
   ```

<h2 id="increase-max_slot_wal_keep_size">
  Increase `max_slot_wal_keep_size`
</h2>

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.

```sql theme={null}
max_slot_wal_keep_size = 102400
```

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

```sql theme={null}
SELECT pg_reload_conf();
```

<Note>
  For better recommendation of this value you can contact the ClickPipes team.
</Note>

<h2 id="whats-next">
  What's next?
</h2>

You can now [create your ClickPipe](/integrations/clickpipes/postgres) 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.