feat(frontend): add description column for SHOW PARAMETERS

src/common/src/system_param/reader.rs

@@ -16,9 +16,17 @@ use std::borrow::Borrow;
 
 use risingwave_pb::meta::PbSystemParams;
 
-use super::{default, system_params_to_kv, ParamValue};
+use super::{default, ParamValue};
 use crate::for_all_params;
 
+/// Information about a system parameter.
+pub struct ParameterInfo {
+    pub name: &'static str,
+    pub mutable: bool,
+    pub value: String,
+    pub description: &'static str,
+}
+
 macro_rules! define_system_params_read_trait {
     ($({ $field:ident, $type:ty, $default:expr, $is_mutable:expr, $doc:literal, $($rest:tt)* },)*) => {
         /// The trait delegating reads on [`risingwave_pb::meta::SystemParams`].
@@ -32,6 +40,20 @@ macro_rules! define_system_params_read_trait {
                 #[doc = $doc]
                 fn $field(&self) -> <$type as ParamValue>::Borrowed<'_>;
             )*
+
+            /// Return the information of all parameters.
+            fn get_all(&self) -> Vec<ParameterInfo> {
+                vec![
+                    $(
+                        ParameterInfo {
+                            name: stringify!($field),
+                            mutable: $is_mutable,
+                            value: self.$field().to_string(),
+                            description: $doc,
+                        },
+                    )*
+                ]
+            }
         }
     };
 }
@@ -70,10 +92,6 @@ where
         }
     }
 
-    pub fn to_kv(&self) -> Vec<(String, String)> {
-        system_params_to_kv(self.inner()).unwrap()
-    }
-
     fn inner(&self) -> &PbSystemParams {
         self.inner.borrow()
     }

src/frontend/src/handler/variable.rs

@@ -18,7 +18,7 @@ use pgwire::pg_protocol::ParameterStatus;
 use pgwire::pg_response::{PgResponse, StatementType};
 use pgwire::types::Row;
 use risingwave_common::session_config::{ConfigReporter, SESSION_CONFIG_LIST_SEP};
-use risingwave_common::system_param::is_mutable;
+use risingwave_common::system_param::reader::SystemParamsRead;
 use risingwave_common::types::{DataType, ScalarRefImpl};
 use risingwave_sqlparser::ast::{Ident, SetTimeZoneValue, SetVariableValue, Value};
 use risingwave_sqlparser::keywords::Keyword;
@@ -158,13 +158,18 @@ async fn handle_show_system_params(handler_args: HandlerArgs) -> Result<Vec<Row>
         .get_system_params()
         .await?;
     let rows = params
-        .to_kv()
+        .get_all()
         .into_iter()
-        .map(|(k, v)| {
-            let is_mutable_bytes = ScalarRefImpl::Bool(is_mutable(&k).unwrap())
+        .map(|info| {
+            let is_mutable_bytes = ScalarRefImpl::Bool(info.mutable)
                 .text_format(&DataType::Boolean)
                 .into();
-            Row::new(vec![Some(k.into()), Some(v.into()), Some(is_mutable_bytes)])
+            Row::new(vec![
+                Some(info.name.into()),
+                Some(info.value.into()),
+                Some(info.description.into()),
+                Some(is_mutable_bytes),
+            ])
         })
         .collect_vec();
     Ok(rows)

src/frontend/src/utils/infer_stmt_row_desc.rs

@@ -232,6 +232,11 @@ pub fn infer_show_variable(name: &str) -> Vec<PgFieldDescriptor> {
                 DataType::Varchar.to_oid(),
                 DataType::Varchar.type_len(),
             ),
+            PgFieldDescriptor::new(
+                "Description".to_string(),
+                DataType::Varchar.to_oid(),
+                DataType::Varchar.type_len(),
+            ),
             PgFieldDescriptor::new(
                 "Mutable".to_string(),
                 DataType::Boolean.to_oid(),