Merge pull request #274587 from varun-dhawan/varund-jul

[Postgres] appends the doc for Extension version sync

Author: prmerger-automator[bot]

articles/postgresql/flexible-server/concepts-extensions.md

@@ -4,7 +4,7 @@ description: Learn about the available PostgreSQL extensions in Azure Database f
 author: varun-dhawan
 ms.author: varundhawan
 ms.reviewer: maghan
-ms.date: 04/27/2024
+ms.date: 05/7/2024
 ms.service: postgresql
 ms.subservice: flexible-server
 ms.topic: conceptual
@@ -101,6 +101,38 @@ The following extensions are available in Azure Database for PostgreSQL flexible
 
 [!INCLUDE [extensions-table](./includes/extensions-table.md)]
 
+## Upgrading PostgreSQL extensions
+In-place upgrades of database extensions are allowed through a simple command. This feature enables customers to automatically update their third-party extensions to the latest versions, maintaining current and secure systems without manual effort.
+
+### Updating Extensions
+To update an installed extension to the latest available version supported by Azure, use the following SQL command:
+
+```sql
+ALTER EXTENSION <extension-name> UPDATE;
+```
+
+This command simplifies the management of database extensions by automatically upgrading to the latest version approved by Azure, enhancing both compatibility and security.
+
+### Limitations
+While updating extensions is straightforward, there are certain limitations:
+- **Specific Version Selection**: The command does not support updating to intermediate versions of an extension. It will always update to the latest available version.
+- **Downgrading**: Azure does not currently support downgrading an extension to a previous version through a similar command. If a downgrade is necessary, it might require manual intervention or support assistance.
+
+#### Viewing Installed Extensions
+To list the extensions currently installed on your database, use the following SQL command:
+
+```sql
+SELECT * FROM pg_extension;
+```
+
+#### Available Extension Versions
+To check which versions of an extension are available for your current database installation, execute:
+
+```sql
+SELECT * FROM pg_available_extension_versions;
+```
+These commands provide necessary insights into the extension configurations of your database, helping maintain your systems efficiently and securely. By enabling easy updates to the latest extension versions, Azure Database for PostgreSQL - Flexible Server continues to support the robust, secure, and efficient management of your database applications.
+
 ## dblink and postgres_fdw
 
 [dblink](https://www.postgresql.org/docs/current/contrib-dblink-function.html) and [postgres_fdw](https://www.postgresql.org/docs/current/postgres-fdw.html) allow you to connect from one Azure Database for PostgreSQL flexible server instance to another, or to another database in the same server. Azure Database for PostgreSQL flexible server supports both incoming and outgoing connections to any PostgreSQL server. The sending server needs to allow outbound connections to the receiving server. Similarly, the receiving server needs to allow connections from the sending server.