CDC - PostgreSQL Setup Documentation

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Prerequisites

To setup CDC between your PostgreSQL database and Peaka Big Table, you need:

• PostgreSQL version 10+
• PostgreSQL administrative permissions.

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Setup Instructions

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Setting up permissions

Create a database user for Peaka’s exclusive use that can perform replication.

( Although, by default, superusers have the necessary REPLICATION and LOGINroles, you can create another user that has the minimum required privileges. )

1. To provide a user with replication permissions, define a PostgreSQL role that has at least the REPLICATION and LOGIN permissions, and then grant that role to the user. For example:

CREATE ROLE <role> REPLICATION LOGIN;

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Configure the PostgreSQL server to logical replication with the pgoutput plugin

1. Set the wal_level parameter in your database configuration to logical. For a standard PostgreSQL database, do this by adding a wal_level = logical line to the postgresql.conf file. Restart the server for this change to take effect.

2. Ensure that your max_replication_slots value is equal to or higher than the number of PostgreSQL connectors that use WAL plus the number of other replication slots your database uses.

3. Create a publication for your tables.

   1. If the user you provide the Peaka connection with has superuser permissions, the publication is created at start-up automatically, if it does not already exist.

   b. You can create a publication for all of your tables.

   CREATE PUBLICATION <publication_name> FOR ALL TABLES;
   

   c. Alternatively, you can create a publication for only tables under the cached schema.

   CREATE PUBLICATION <publication_name> FOR TABLES IN SCHEMA <schema_name>;
   

4. Create a logical replication slot (Optional)

   SELECT pg_create_logical_replication_slot(<slot_name>, 'pgoutput');
   

   Note: since a replication slot can only be used by a single connector, it is essential to create a unique replication slot for each CDC connection.