diff --git a/cpp/CHANGELOG.md b/cpp/CHANGELOG.md
index 60374fa3100e35620c782088fec786b78a53fe49..6dc2369b47ec0d1f6f79fe0591bd3394823e5301 100644
--- a/cpp/CHANGELOG.md
+++ b/cpp/CHANGELOG.md
@@ -7,6 +7,7 @@ Please mark all change in change log and use the ticket from JIRA.
 ## Bug
 - MS-568 - Fix gpuresource free error
 - MS-572 - Milvus crash when get SIGINT
+- MS-577 - Unittest Query randomly hung
 
 ## Improvement
 - MS-552 - Add and change the easylogging library
diff --git a/cpp/src/scheduler/JobMgr.cpp b/cpp/src/scheduler/JobMgr.cpp
index c5c14c1b414cfb2843304d5cbfd3ed088c0e0494..31db4b344ef35bad3e5ecd5e020f1eb91029afac 100644
--- a/cpp/src/scheduler/JobMgr.cpp
+++ b/cpp/src/scheduler/JobMgr.cpp
@@ -32,8 +32,8 @@ JobMgr::JobMgr(ResourceMgrPtr res_mgr)
 void
 JobMgr::Start() {
     if (not running_) {
-        worker_thread_ = std::thread(&JobMgr::worker_function, this);
         running_ = true;
+        worker_thread_ = std::thread(&JobMgr::worker_function, this);
     }
 }