add alter system command and use it for system wide session config (#2092)

Chengyi-Ying · ShanlanLi · web-flow · commit 77d522e49522 · 2024-04-28T15:09:15.000+08:00
* feat(session_config)

* Update view-configure-system-parameters.md

* add alter system command and made small modification

* Update docs/manage/view-configure-runtime-parameters.md

---------

Co-authored-by: Shanlan(Lily) &lt;150168166+ShanlanLi@users.noreply.github.com&gt;
diff --git a/docs/manage/view-configure-runtime-parameters.md b/docs/manage/view-configure-runtime-parameters.md
@@ -98,3 +98,10 @@ SET parameter_name { TO | = } { value | 'value' | DEFAULT};
 Where `parameter_name` is the name of the parameter, and `value` or `'value'` is the new value of the parameter. `DEFAULT` can be written to specify resetting the parameter to its default value.
 
 For details about the `set_config()` function, see [System administration functions](/sql/functions-operators/sql-function-sys-admin.md#set_config), and for details about the `SET` command, see [`SET`](/sql/commands/sql-set.md).
+
+
+You can also use the [`ALTER SYSTEM SET`](/sql/commands/sql-alter-system.md) command to set a system-wide default value for a runtime parameter. This configuration will then be applied to every new session.
+
+```sql title="Syntax"
+ALTER SYSTEM SET session_param_name TO session_param_value;
+```
diff --git a/docs/sql/commands/sql-alter-system.md b/docs/sql/commands/sql-alter-system.md
@@ -0,0 +1,21 @@
+---
+id: sql-alter-system
+title: ALTER SYSTEM
+description: Modify a server configuration parameter.
+slug: /sql-alter-system
+---
+<head>
+  <link rel="canonical" href="https://docs.risingwave.com/docs/current/sql-alter-system/" />
+</head>
+
+The `ALTER SYSTEM` command modifies the value of a server configuration parameter. You can use this command to configure some parameters, like the [system parameters](/manage/view-configure-system-parameters.md#how-to-configure-system-parameters) and [runtime parameters](/manage/view-configure-runtime-parameters.md#how-to-configure-runtime-parameters). 
+
+```sql title="Syntax"
+ALTER SYSTEM SET configuration_parameter { TO | = } { value [, ...] | DEFAULT }
+```
+
+
+```sql title="Examples"
+ALTER SYSTEM SET rw_streaming_enable_delta_join TO true;
+```
+
