diff --git a/e2e_test/error_ui/simple/main.slt b/e2e_test/error_ui/simple/main.slt
index 8ef82e1f0d1c7..6bcbbde608cf8 100644
--- a/e2e_test/error_ui/simple/main.slt
+++ b/e2e_test/error_ui/simple/main.slt
@@ -13,8 +13,10 @@ create function int_42() returns int as int_42 using link '555.0.0.1:8815';
 ----
 db error: ERROR: Failed to run the query
 
-Caused by:
-  Flight service error: invalid address: 555.0.0.1:8815, err: failed to parse address: http://555.0.0.1:8815: invalid IPv4 address
+Caused by these errors (recent errors listed first):
+  1: Expr error
+  2: UDF error
+  3: Flight service error: invalid address: 555.0.0.1:8815, err: failed to parse address: http://555.0.0.1:8815: invalid IPv4 address
 
 
 statement error
diff --git a/src/expr/core/src/expr/expr_udf.rs b/src/expr/core/src/expr/expr_udf.rs
index 220fdc2742cd6..54d3006dc3033 100644
--- a/src/expr/core/src/expr/expr_udf.rs
+++ b/src/expr/core/src/expr/expr_udf.rs
@@ -421,7 +421,7 @@ impl Build for UserDefinedFunction {
             #[cfg(not(madsim))]
             _ => {
                 let link = udf.get_link()?;
-                let client = crate::expr::expr_udf::get_or_create_flight_client(link)?;
+                let client = get_or_create_flight_client(link)?;
                 // backward compatibility
                 // see <https://github.com/risingwavelabs/risingwave/pull/16619> for details
                 if client.protocol_version() == 1 {
@@ -456,11 +456,11 @@ impl Build for UserDefinedFunction {
     }
 }
 
-#[cfg(not(madsim))]
+#[cfg_or_panic(not(madsim))]
 /// Get or create a client for the given UDF service.
 ///
 /// There is a global cache for clients, so that we can reuse the same client for the same service.
-pub(crate) fn get_or_create_flight_client(link: &str) -> Result<Arc<FlightClient>> {
+pub fn get_or_create_flight_client(link: &str) -> Result<Arc<FlightClient>> {
     static CLIENTS: LazyLock<std::sync::Mutex<HashMap<String, Weak<FlightClient>>>> =
         LazyLock::new(Default::default);
     let mut clients = CLIENTS.lock().unwrap();
@@ -489,11 +489,11 @@ async fn connect_tonic(mut addr: &str) -> Result<tonic::transport::Channel> {
     const REQUEST_TIMEOUT_SECS: u64 = 5;
     const CONNECT_TIMEOUT_SECS: u64 = 5;
 
-    if addr.starts_with("http://") {
-        addr = addr.strip_prefix("http://").unwrap();
+    if let Some(s) = addr.strip_prefix("http://") {
+        addr = s;
     }
-    if addr.starts_with("https://") {
-        addr = addr.strip_prefix("https://").unwrap();
+    if let Some(s) = addr.strip_prefix("https://") {
+        addr = s;
     }
     let host_addr = addr.parse::<HostAddr>().map_err(|e| {
         arrow_udf_flight::Error::Service(format!(
diff --git a/src/expr/core/src/expr/mod.rs b/src/expr/core/src/expr/mod.rs
index 6dbb3906f5618..9188ced21d111 100644
--- a/src/expr/core/src/expr/mod.rs
+++ b/src/expr/core/src/expr/mod.rs
@@ -51,7 +51,7 @@ use risingwave_common::types::{DataType, Datum};
 pub use self::build::*;
 pub use self::expr_input_ref::InputRefExpression;
 pub use self::expr_literal::LiteralExpression;
-pub use self::expr_udf::get_or_create_wasm_runtime;
+pub use self::expr_udf::{get_or_create_flight_client, get_or_create_wasm_runtime};
 pub use self::value::{ValueImpl, ValueRef};
 pub use self::wrapper::*;
 pub use super::{ExprError, Result};
diff --git a/src/frontend/src/handler/create_function.rs b/src/frontend/src/handler/create_function.rs
index 88172293cb458..471145a12a3e4 100644
--- a/src/frontend/src/handler/create_function.rs
+++ b/src/frontend/src/handler/create_function.rs
@@ -12,16 +12,15 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use anyhow::{anyhow, Context};
+use anyhow::Context;
 use arrow_schema::Fields;
-use arrow_udf_flight::Client as FlightClient;
 use bytes::Bytes;
 use itertools::Itertools;
 use pgwire::pg_response::StatementType;
 use risingwave_common::array::arrow::{ToArrow, UdfArrowConvert};
 use risingwave_common::catalog::FunctionId;
 use risingwave_common::types::DataType;
-use risingwave_expr::expr::get_or_create_wasm_runtime;
+use risingwave_expr::expr::{get_or_create_flight_client, get_or_create_wasm_runtime};
 use risingwave_pb::catalog::function::{Kind, ScalarFunction, TableFunction};
 use risingwave_pb::catalog::Function;
 use risingwave_sqlparser::ast::{CreateFunctionBody, ObjectName, OperateFunctionArg};
@@ -167,7 +166,7 @@ pub async fn handle_create_function(
 
             // check UDF server
             {
-                let client = FlightClient::connect(&l).await.map_err(|e| anyhow!(e))?;
+                let client = get_or_create_flight_client(&l)?;
                 let convert = UdfArrowConvert {
                     legacy: client.protocol_version() == 1,
                 };