diff --git a/internal/core/src/config/ConfigKnowhere.cpp b/internal/core/src/config/ConfigKnowhere.cpp
index cfe2358762..8315559884 100644
--- a/internal/core/src/config/ConfigKnowhere.cpp
+++ b/internal/core/src/config/ConfigKnowhere.cpp
@@ -45,6 +45,7 @@ KnowhereInitImpl(const char* conf_file) {
             gflags::SetCommandLineOption("flagfile", conf_file);
         }
 #endif
+        setbuf(stdout, NULL);
     };
 
     std::call_once(init_knowhere_once_, init);