How to enable plugins/extensions
This guide outlines the steps for enabling an extension in a Charmed PostgreSQL deployment.
For a list of available extensions, see the page Supported plugins/extensions. The words “plugin” and “extension” will be used interchangeably.
Prerequisites
Enable extension
Enable the extension by setting True as the value of its respective config option, like in the following example:
juju config postgresql plugin_<plugin name>_enable=True
Integrate your application
Integrate (formerly known as “relate” in juju v.2.9) your application charm with the PostgreSQL charm:
juju integrate <application charm> postgresql
If your application charm requests extensions through db or db-admin relation data, but the extension is not enabled yet, you’ll see that the PostgreSQL application goes into a blocked state with the following message:
postgresql/0* blocked idle 10.1.123.30 extensions requested through relation
In the Juju debug logs we can see the list of extensions that need to be enabled:
unit-postgresql-0: 18:04:51 ERROR unit.postgresql/0.juju-log db:5: ERROR - `extensions` (pg_trgm, unaccent) cannot be requested through relations - Please enable extensions through `juju config` and add the relation again.
After enabling the needed extensions through the config options, the charm will unblock. If you have removed the relation, you can add it back again.
If the application charm uses the new postgresql_client interface, it can use the is_postgresql_plugin_enabled helper method from the data interfaces library to check whether the plugin/extension is already enabled in the database.
Note: Not all PostgreSQL extensions are available. The list of supported extensions is available at Supported plugins/extensions.