diff --git a/src/observer/virtual_table/ob_all_virtual_session_info.cpp b/src/observer/virtual_table/ob_all_virtual_session_info.cpp
index 6ca644a51..ac2a9fce3 100644
--- a/src/observer/virtual_table/ob_all_virtual_session_info.cpp
+++ b/src/observer/virtual_table/ob_all_virtual_session_info.cpp
@@ -296,6 +296,7 @@ int ObAllVirtualSessionInfo::FillScanner::operator()(
             } else {
               cur_row_->cells_[cell_idx].set_varchar("");
             }
+            cur_row_->cells_[cell_idx].set_collation_type(default_collation);
             break;
           }
           case USER_CLIENT_PORT: {