Google Cloud PostgreSQL

Prerequisites

IP address or host name of your PostgreSQL server is available.
The PostgreSQL version is 9.4 or higher.
Hevo’s IP addresses are whitelisted.
SELECT, USAGE, and CONNECT privileges are granted to the database user.
If the Pipeline mode is Logical Replication:
- Log-based incremental replication is enabled.
- PostgreSQL database instance is a master instance.
  
  Note: PostgreSQL does not support logical replication for the read replica.

Perform the following steps to configure your Google Cloud PostgreSQL Source:

Set up Log-based Incremental Replication (optional)

Note: If you are not using Logical Replication, skip this step.

PostgreSQL (version 9.4 and above) supports logical replication by writing additional information to its Write Ahead Logs (WALs).

To configure logical replication:

Go to the Google Cloud SQL instance.
Click the More icon next to the PostgreSQL instance and click Edit.
Scroll down to the Flags section.
Click the More icon next to the PostgreSQL instance name and click Edit.
Scroll down to the Flags section.
Click the drop-down next to Flags and then click Add Flag.

Select all four flags from the drop-down menu. Specify their values as follows:

Setting	Value	Description
`cloudsql.enable_pglogical`	On	The setting to enable or disable the `pglogical` extension. Default value: Off.
`cloudsql.logical_decoding`	On	The setting to enable or disable logical replication. Default value: Off.
`max_replication_slots`	10	The number of clients that can connect to the server. Default value: 10.
`max_wal_senders`	10	The number of processes that can simultaneously transmit the WAL log. Default value: 10.
`wal_sender_timeout`	0	The time, in seconds, after which PostgreSQL terminates the replication connections due to inactivity. Default value: 60 seconds. You must set the value to 0 so that the connections are never terminated and your Pipeline does not fail. You can use the following query to check the value configured for the parameter: `show wal_sender_timeout`

Click Save. The settings you configured are displayed under the Flags section.

Whitelist Hevo’s IP Addresses

You need to whitelist the Hevo IP addresses for your region to enable Hevo to connect to your PostgreSQL database. To do this:

Access the Google Cloud console and click on your PostgeSQL instance ID.
In the left navigation pane, click Connections.
Select the Public IP check box to activate access on any custom IP address.
Click Add Network, and include the list of Hevo IP addresses available for your region.
Repeat the above step for all the network addresses you want to add.
Click Save. You can see Hevo’s IP addresses under Authorized networks.

Create a Replication User and Grant Privileges

While using logical replication in Google Cloud PostgreSQL, the user must have the cloudsqlsuperuser role. This role is needed to run the CREATE EXTENSION command.

Create a PostgreSQL user with REPLICATION privileges as follows:

Log in to your PostgreSQL database using any SQL client like DataGrip as a super admin and run the following commands:
```
 CREATE USER replication_user WITH REPLICATION
 IN ROLE cloudsqlsuperuser LOGIN PASSWORD 'secret';
```
Alternatively, set this attribute for an existing user as follows:
```
 ALTER USER existing_user WITH REPLICATION;
```

Enter the following commands to provide access to the database user:

 GRANT CONNECT ON DATABASE <database_name> TO <database_username>;
 GRANT USAGE ON SCHEMA <schema_name> TO <database_username>;
 GRANT SELECT ON DATABASE <database_name> TO <database_username>;

Alter the schema’s default privileges to grant SELECT privileges on tables to the database user:

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

Limitations

The data type Array in the Source is automatically mapped to Varchar at the Destination. No other mapping is currently supported.

Revision History

Refer to the following table for the list of key updates made to this page:

Date	Release	Description of Change
Mar-07-2022	1.83	Updated the section, Prerequisites with a note about the logical replication.
Jan-24-2022	1.80	Removed from Limitations that Hevo does not support UUID datatype as primary key.
Dec-20-2021	1.78	Updated section, Set up Log-based Incremental Replication.
Sep-09-2021	1.71	- Updated the section, Limitations to include information about columns with the UUID data type not being supported as a primary key. - Added WAL replication mode in the Prerequisites section. - Replaced the section Grant Privileges to the User with Create a Replication User and Grant Privileges.
Jun-14-2021	1.65	Updated the Grant Privileges to the User section to include latest commands.

Last updated on 22 Mar 2022