diff --git a/src/operator/src/insert.rs b/src/operator/src/insert.rs
index b12bd91989..5d27de039b 100644
--- a/src/operator/src/insert.rs
+++ b/src/operator/src/insert.rs
@@ -580,6 +580,10 @@ impl Inserter {
                 // for it's a very unexpected behavior and should be set by user explicitly
                 for mut create_table in create_tables {
                     if create_table.table_name == trace_services_table_name(trace_table_name) {
+                        // Disable append mode for trace services table since it requires upsert behavior.
+                        create_table
+                            .table_options
+                            .insert(APPEND_MODE_KEY.to_string(), "false".to_string());
                         let table = self
                             .create_physical_table(create_table, None, ctx, statement_executor)
                             .await?;
diff --git a/src/servers/src/otlp/trace/v1.rs b/src/servers/src/otlp/trace/v1.rs
index 86d4112807..68dfff0a97 100644
--- a/src/servers/src/otlp/trace/v1.rs
+++ b/src/servers/src/otlp/trace/v1.rs
@@ -176,9 +176,9 @@ fn write_trace_services_to_row(writer: &mut TableData, services: HashSet<String>
         )?;
 
         // Write the `service_name` column.
-        row_writer::write_fields(
+        row_writer::write_tags(
             writer,
-            std::iter::once(make_string_column_data(SERVICE_NAME_COLUMN, service_name)),
+            std::iter::once((SERVICE_NAME_COLUMN.to_string(), service_name)),
             &mut row,
         )?;
         writer.add_row(row);
diff --git a/tests-integration/tests/http.rs b/tests-integration/tests/http.rs
index f02d25dbd6..7ce500b9b1 100644
--- a/tests-integration/tests/http.rs
+++ b/tests-integration/tests/http.rs
@@ -2838,7 +2838,7 @@ pub async fn test_otlp_traces_v1(store_type: StorageType) {
     )
     .await;
 
-    let expected_ddl = r#"[["mytable_services","CREATE TABLE IF NOT EXISTS \"mytable_services\" (\n  \"timestamp\" TIMESTAMP(9) NOT NULL,\n  \"service_name\" STRING NULL,\n  TIME INDEX (\"timestamp\")\n)\n\nENGINE=mito\nWITH(\n  append_mode = 'true'\n)"]]"#;
+    let expected_ddl = r#"[["mytable_services","CREATE TABLE IF NOT EXISTS \"mytable_services\" (\n  \"timestamp\" TIMESTAMP(9) NOT NULL,\n  \"service_name\" STRING NULL,\n  TIME INDEX (\"timestamp\"),\n  PRIMARY KEY (\"service_name\")\n)\n\nENGINE=mito\nWITH(\n  append_mode = 'false'\n)"]]"#;
     validate_data(
         "otlp_traces",
         &client,