diff --git a/src/common/inc/tglobal.h b/src/common/inc/tglobal.h
index 1e1e2617a953e6d4156e3032266bc8b1bdf8090d..8a6cc9ddb5a4425e3d7bd10bb7dd5dda0712b0c3 100644
--- a/src/common/inc/tglobal.h
+++ b/src/common/inc/tglobal.h
@@ -209,7 +209,7 @@ extern int32_t wDebugFlag;
 extern int32_t cqDebugFlag;
 extern int32_t debugFlag;
 
-int8_t tsClientMerge;
+extern int8_t tsClientMerge;
 
 #ifdef TD_TSZ
 // lossy